diff --git a/packages/app/e2e/performance/timeline-stability/fixture.ts b/packages/app/e2e/performance/timeline-stability/fixture.ts
index 3f663c4aaad..6d7b9ec37a5 100644
--- a/packages/app/e2e/performance/timeline-stability/fixture.ts
+++ b/packages/app/e2e/performance/timeline-stability/fixture.ts
@@ -11,6 +11,7 @@ import type {
 } from "@opencode-ai/client/promise"
 import { EventManifest } from "@opencode-ai/schema/event-manifest"
 import { SessionMessage } from "@opencode-ai/schema/session-message"
+import type { TimelineDetail } from "@opencode-ai/session-ui/timeline/detail"
 import { expect, type Page } from "@playwright/test"
 import { Schema } from "effect"
 import { mockOpenCodeServer } from "../../utils/mock-server"
@@ -122,7 +123,7 @@ export async function setupTimeline(
     messages?: TimelineMessage[]
     sessionMessages?: SessionMessageInfo[]
     sessionStatus?: Record<string, SessionStatus>
-    settings?: Record<string, boolean>
+    settings?: Record<string, boolean | TimelineDetail>
     sessions?: Session[]
     cpuRate?: number
     viewport?: { width: number; height: number }
diff --git a/packages/app/e2e/regression/session-location-sync.spec.ts b/packages/app/e2e/regression/session-location-sync.spec.ts
index f281b263475..84989914c49 100644
--- a/packages/app/e2e/regression/session-location-sync.spec.ts
+++ b/packages/app/e2e/regression/session-location-sync.spec.ts
@@ -67,6 +67,12 @@ test("follows a live session move while the agent catalog is still loading", asy
   const session = { id: sessionID, projectID: fixture.project.id, directory, title: "Moved session" }
   const requested = Promise.withResolvers<void>()
   const release = Promise.withResolvers<void>()
+  await page.addInitScript(() => {
+    localStorage.setItem(
+      "settings.v3",
+      JSON.stringify({ general: { timelineDetail: { notices: { placement: "separate" } } } }),
+    )
+  })
   const transport = await installSseTransport(page, { server: fixture.serverKey })
   await mockOpenCodeServer(page, {
     directory: fixture.directory,
@@ -95,9 +101,7 @@ test("follows a live session move while the agent catalog is still loading", asy
   await transport.waitForConnection()
   const resolved = page.waitForResponse((response) => {
     const url = new URL(response.url())
-    return (
-      url.pathname === "/api/agent" && url.searchParams.get("location[directory]") === destination && response.ok()
-    )
+    return url.pathname === "/api/agent" && url.searchParams.get("location[directory]") === destination && response.ok()
   })
   session.directory = destination
   await transport.send({
@@ -221,7 +225,8 @@ function recoveryRequests(page: Page) {
   const requests: string[] = []
   page.on("request", (request) => {
     const path = new URL(request.url()).pathname
-    if (request.method() === "POST" && /^\/api\/(session\/[^/]+\/move$|worktree(?:\/|$))/.test(path)) requests.push(path)
+    if (request.method() === "POST" && /^\/api\/(session\/[^/]+\/move$|worktree(?:\/|$))/.test(path))
+      requests.push(path)
   })
   return requests
 }
diff --git a/packages/app/e2e/regression/session-notice-truncation.spec.ts b/packages/app/e2e/regression/session-notice-truncation.spec.ts
index bd5e1a79083..f8e847245f5 100644
--- a/packages/app/e2e/regression/session-notice-truncation.spec.ts
+++ b/packages/app/e2e/regression/session-notice-truncation.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import { setupTimeline } from "../performance/timeline-stability/fixture"
 
 for (const width of [1400, 390]) {
@@ -16,6 +17,9 @@ for (const width of [1400, 390]) {
         `\u0645\u0631\u0627\u062c\u0639\u0629 ${command}--reviewed`,
       ]
       await setupTimeline(page, {
+        settings: {
+          timelineDetail: { ...timelinePresets[2].value, notices: { placement: "separate" } },
+        },
         locale: profile.locale,
         viewport: { width, height: 900 },
         sessionMessages: [
diff --git a/packages/app/e2e/regression/session-timeline-file-projection.spec.ts b/packages/app/e2e/regression/session-timeline-file-projection.spec.ts
index bd14afe5d1b..c6e0c671dba 100644
--- a/packages/app/e2e/regression/session-timeline-file-projection.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-file-projection.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import { createTwoFilesPatch } from "diff"
 import {
   assistantMessage,
@@ -36,7 +37,9 @@ test("renders a completed single-file patch", async ({ page }) => {
         ),
       ]),
     ],
-    settings: { editToolPartsExpanded: true },
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, edit: { placement: "separate", details: "collapsed" } },
+    },
   })
 
   const wrapper = page.locator(`[data-timeline-part-id="${id}"]`)
@@ -68,7 +71,9 @@ test("keeps an expanded file diff header at the same viewport position", async (
   const before = Array.from({ length: 80 }, (_, index) => `export const value${index} = ${index}\n`).join("")
   const after = before.replaceAll(" = ", " = compute(").replaceAll("\n", ")\n")
   await setupTimeline(page, {
-    settings: { editToolPartsExpanded: true },
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, edit: { placement: "separate", details: "collapsed" } },
+    },
     messages: [
       userMessage([userText("Preceding context ".repeat(120))]),
       assistantMessage([
@@ -100,6 +105,7 @@ test("keeps an expanded file diff header at the same viewport position", async (
   const wrapper = page.locator(`[data-timeline-part-id="${id}"]`)
   const row = page.locator("[data-timeline-key]", { has: wrapper })
   const trigger = wrapper.getByRole("button")
+  await expect(trigger).toHaveAttribute("aria-expanded", "false")
   await expect
     .poll(() =>
       row.evaluate((element) => {
diff --git a/packages/app/e2e/regression/session-timeline-lifecycle-state.spec.ts b/packages/app/e2e/regression/session-timeline-lifecycle-state.spec.ts
index 1223b7b8e84..90447e05978 100644
--- a/packages/app/e2e/regression/session-timeline-lifecycle-state.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-lifecycle-state.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import {
   assistantID,
   assistantMessage,
@@ -23,20 +24,23 @@ for (const expanded of [false, true]) {
   test(`preserves shell user intent from a ${expanded ? "expanded" : "collapsed"} default`, async ({ page }) => {
     const id = `prt_shell_default_${expanded}`
     const timeline = await setupTimeline(page, {
-      messages: [userMessage(), assistantMessage([shell(id, "completed", lines(3))])],
-      settings: { shellToolPartsExpanded: expanded },
+      messages: [userMessage(), assistantMessage([shell(id, "running", lines(3))], { completed: false })],
+      settings: {
+        timelineDetail: {
+          ...timelinePresets[2].value,
+          shell: { placement: "separate", details: expanded ? "expanded" : "collapsed" },
+        },
+      },
     })
-    const trigger = expanded
-      ? page.locator(`[data-timeline-part-id="${id}"] [data-slot="collapsible-trigger"]`)
-      : page.getByRole("button", { name: "Used 1 Shell", exact: true })
+    const trigger = page.locator(`[data-timeline-part-id="${id}"] [data-slot="collapsible-trigger"]`)
     await expect(trigger).toHaveAttribute("aria-expanded", String(expanded))
     await trigger.click()
     await expect(trigger).toHaveAttribute("aria-expanded", String(!expanded))
 
-    await timeline.send(partUpdated(shell(id, "completed", lines(6))), 180)
-    await timeline.send(partUpdated(textPart(`prt_sibling_${expanded}`, "Sibling content")), 180)
-    await timeline.send(status("busy"), 100)
-    await timeline.send(status("idle"), 250)
+    await timeline.send(partUpdated(shell(id, "completed", lines(6))))
+    await timeline.send(partUpdated(textPart(`prt_sibling_${expanded}`, "Sibling content")))
+    await timeline.send(status("idle"))
+    await expect(page.getByText("Sibling content", { exact: true })).toBeVisible()
     await expect(trigger).toHaveAttribute("aria-expanded", String(!expanded))
   })
 }
@@ -46,6 +50,9 @@ test("transitions a streaming shell from writing through command execution", asy
   const command = "printf ready"
   const timeline = await setupTimeline(page, {
     messages: [userMessage(), assistantMessage([], { completed: false })],
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, shell: { placement: "separate", details: "collapsed" } },
+    },
   })
   await timeline.send(toolInputStarted({ sessionID, assistantMessageID: assistantID, id, name: "shell" }))
 
@@ -95,7 +102,9 @@ test("shimmers and expands a running shell command", async ({ page }) => {
   const command = "sleep 10 && echo done"
   await setupTimeline(page, {
     messages: [userMessage(), assistantMessage([shell(id, "running", "still running", command)], { completed: false })],
-    settings: { shellToolPartsExpanded: false },
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, shell: { placement: "separate", details: "collapsed" } },
+    },
   })
 
   const tool = page.locator(`[data-timeline-part-id="${id}"]`)
@@ -110,7 +119,7 @@ test("shimmers and expands a running shell command", async ({ page }) => {
 })
 
 for (const open of [false, true]) {
-  test(`keeps ${open ? "expanded" : "collapsed"} reasoning intent from Thinking through standalone shell into Used`, async ({
+  test(`keeps ${open ? "expanded" : "collapsed"} Separate reasoning intent through shell completion`, async ({
     page,
   }) => {
     const reasoningID = `prt_reasoning_hidden_${open}`
@@ -118,7 +127,13 @@ for (const open of [false, true]) {
     const assistant = assistantMessage([reasoningPart(reasoningID, "## Inspecting stability")], { completed: false })
     const timeline = await setupTimeline(page, {
       messages: [userMessage(), assistant],
-      settings: { showReasoningSummaries: false },
+      settings: {
+        timelineDetail: {
+          ...timelinePresets[2].value,
+          thinking: { placement: "separate", details: "collapsed" },
+          shell: { placement: "separate", details: "collapsed" },
+        },
+      },
       cpuRate: 4,
     })
     const reasoning = page.locator(`[data-timeline-part-id="${renderedPartID(reasoningID)}"]`)
@@ -141,28 +156,11 @@ for (const open of [false, true]) {
     await timeline.send(partUpdated(shell(shellID, "completed", "done")))
     await timeline.send(messageUpdated(completedAssistantInfo(assistant)))
     await timeline.send(status("idle"))
-    const used = group.getByRole("button", { name: "Used 1 Shell", exact: true })
-    await expect(used).toHaveAttribute("aria-expanded", "false")
-    await used.click()
-    await expect(used).toHaveAttribute("aria-expanded", "true")
-    await expect(group.locator(`[data-timeline-part-id="${shellID}"]`)).toBeVisible()
-    await expect(group.getByRole("button", { name: "Thought", exact: true })).toHaveAttribute(
-      "aria-expanded",
-      String(open),
-    )
-    await expect(used.locator('[data-slot="basic-tool-tool-title"]')).toHaveText("1 Shell")
+    await expect(group).toHaveCount(0)
+    await expect(thought).toHaveAttribute("aria-expanded", String(open))
     await expect(page.locator('[data-timeline-row="Thinking"]')).toHaveCount(0)
-    await expect(used).toHaveAttribute("aria-expanded", "true")
     if (!open) await thought.click()
     await expect(reasoning.getByRole("heading", { name: "Inspecting stability", exact: true })).toBeVisible()
-    await used.click()
-    await expect(used).toHaveAttribute("aria-expanded", "false")
-    await used.click()
-    await expect(reasoning.getByRole("button", { name: "Thought", exact: true })).toHaveAttribute(
-      "aria-expanded",
-      "true",
-    )
-    await expect(reasoning.getByRole("heading", { name: "Inspecting stability", exact: true })).toBeVisible()
   })
 }
 
@@ -172,6 +170,9 @@ for (const transition of ["reasoning-end", "idle", "retry"] as const) {
     const text = "## Inspecting stability\n\nThe timeline is ready for the next step."
     const timeline = await setupTimeline(page, {
       messages: [userMessage(), assistantMessage([reasoningPart(id, text)], { completed: false })],
+      settings: {
+        timelineDetail: { ...timelinePresets[2].value, thinking: { placement: "separate", details: "collapsed" } },
+      },
     })
     const part = page.locator(`[data-timeline-part-id="${renderedPartID(id)}"]`)
     const trigger = part.locator('[data-slot="collapsible-trigger"]')
diff --git a/packages/app/e2e/regression/session-timeline-notices.spec.ts b/packages/app/e2e/regression/session-timeline-notices.spec.ts
index 4183fc3c666..fa0039e68fe 100644
--- a/packages/app/e2e/regression/session-timeline-notices.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-notices.spec.ts
@@ -1,5 +1,6 @@
 import { expect, test } from "@playwright/test"
 import type { SessionMessageAssistant, SessionMessageInfo } from "@opencode-ai/client/promise"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import {
   compactionDelta,
   compactionEnded,
@@ -49,6 +50,9 @@ test("renders current protocol notices in CLI order", async ({ page }) => {
       ownerWarnings.push(message.text())
   })
   await setupTimeline(page, {
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, notices: { placement: "separate" } },
+    },
     sessionMessages: [
       user,
       { id: "msg_agent", type: "agent-switched", agent: "explore", time: { created: 2 } },
@@ -84,7 +88,12 @@ test("renders current protocol notices in CLI order", async ({ page }) => {
 })
 
 test("renders a compaction summary while it streams and after completion", async ({ page }) => {
-  const timeline = await setupTimeline(page, { sessionMessages: [user, assistant(true)] })
+  const timeline = await setupTimeline(page, {
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, notices: { placement: "separate" } },
+    },
+    sessionMessages: [user, assistant(true)],
+  })
 
   await timeline.send(
     compactionStarted({
@@ -161,7 +170,12 @@ test("updates running compactions to failed and cancelled boundaries", async ({
 })
 
 test("moves blocking work to the background with Ctrl+B", async ({ page }) => {
-  await setupTimeline(page, { sessionMessages: [user, assistant(false, true)] })
+  await setupTimeline(page, {
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, subagents: { placement: "separate" } },
+    },
+    sessionMessages: [user, assistant(false, true)],
+  })
   const card = page.locator('[data-component="task-tool-card"]')
   await expect(card).toBeVisible()
   await expect(card).toContainText("Inspect code")
@@ -198,6 +212,9 @@ test("moves blocking work to the background with Ctrl+B", async ({ page }) => {
 test("navigates from a running subagent card and hides background controls in the child", async ({ page }) => {
   const childID = "ses_running_child"
   await setupTimeline(page, {
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, subagents: { placement: "separate" } },
+    },
     sessionMessages: [user, assistant(false, true, childID)],
     sessions: [session(), session({ id: childID, parentID: sessionID, title: "Sleep for 5 minutes" })],
     sessionStatus: { [sessionID]: { type: "busy" }, [childID]: { type: "busy" } },
@@ -213,6 +230,7 @@ for (const name of ["shell", "subagent"] as const) {
   test(`keeps the background shortcut available for a grouped running ${name}`, async ({ page }) => {
     const message = assistant(false, true)
     await setupTimeline(page, {
+      settings: { timelineDetail: timelinePresets[2].value },
       sessionMessages: [
         user,
         {
@@ -281,6 +299,7 @@ test("separates blocking and already-backgrounded work into two rows", async ({
   const backgroundID = "ses_background_existing"
   const blockingID = "ses_background_blocking"
   const timeline = await setupTimeline(page, {
+    settings: { timelineDetail: timelinePresets[2].value },
     sessionMessages: [
       user,
       {
@@ -369,6 +388,13 @@ test("separates blocking and already-backgrounded work into two rows", async ({
   })
   const backgroundCard = page.locator('[data-timeline-part-id="call_backgrounded"]')
   await expect(page.getByText(/move running work to the background/i)).toBeVisible()
+  const used = page
+    .locator('[data-timeline-part-ids="call_backgrounded,call_shell_backgrounded,call_blocking"]')
+    .locator(':scope > [data-component="collapsible"] > [data-slot="collapsible-trigger"]')
+  await expect(used).toHaveText(/^Used\s*2 Agent, 1 Shell$/)
+  await expect(used).toHaveAttribute("aria-expanded", "false")
+  await used.click()
+  await expect(used).toHaveAttribute("aria-expanded", "true")
   await page.getByRole("button", { name: "Session details" }).click()
   const summary = page.getByRole("button", { name: "2 items running in background" })
   await expect(summary).toContainText("2")
@@ -376,6 +402,7 @@ test("separates blocking and already-backgrounded work into two rows", async ({
   const list = page.locator('[data-component="session-background-list"]')
   await expect(list).toContainText("Background task")
   await expect(list).toContainText("sleep 120")
+  await expect(list).not.toContainText("Foreground task")
   await expect(backgroundCard).toContainText("Background task (background)")
   await expect(backgroundCard.locator('[data-component="session-progress-indicator-v2"]')).toBeVisible()
   await expect(
diff --git a/packages/app/e2e/regression/session-timeline-projection.spec.ts b/packages/app/e2e/regression/session-timeline-projection.spec.ts
index ba0b730f310..cc3dfcc96ea 100644
--- a/packages/app/e2e/regression/session-timeline-projection.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-projection.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import {
   assistantMessage,
   partUpdated,
@@ -14,7 +15,9 @@ test.describe("session timeline projection", () => {
     const first = "prt_patch_first"
     const second = "prt_patch_second"
     const timeline = await setupTimeline(page, {
-      settings: { editToolPartsExpanded: true },
+      settings: {
+        timelineDetail: { ...timelinePresets[2].value, edit: { placement: "separate", details: "collapsed" } },
+      },
       messages: [
         userMessage(),
         assistantMessage([
@@ -34,6 +37,7 @@ test.describe("session timeline projection", () => {
     const initial = page.locator(`[data-timeline-part-id="${first}"]`)
     const initialFile = initial.locator('[data-scope="apply-patch"] [data-type="update"]')
     await expect(initialFile).toBeVisible()
+    await expect(initialFile.getByRole("button")).toHaveAttribute("aria-expanded", "false")
     await initialFile.getByRole("button").click()
     await expect(initialFile.getByRole("button")).toHaveAttribute("aria-expanded", "true")
     await initial.evaluate((element) => {
@@ -110,8 +114,11 @@ test.describe("session timeline projection", () => {
       parentID: "msg_2000_second_user",
       created: 1700000006000,
     })
-    const timeline = await setupTimeline(page, { messages: [firstUser, aborted, failed, nextUser, nextAssistant] })
-    await timeline.send(status("idle"), 100)
+    const timeline = await setupTimeline(page, {
+      settings: { timelineDetail: timelinePresets[2].value },
+      messages: [firstUser, aborted, failed, nextUser, nextAssistant],
+    })
+    await timeline.send(status("idle"))
     const scroller = page.locator(".scroll-view__viewport", { has: page.locator("[data-timeline-row]") })
     await scroller.evaluate((element) => (element.scrollTop = 0))
 
@@ -127,6 +134,7 @@ test.describe("session timeline projection", () => {
     const longName = "Company Gateway Extra Long Context Model for Narrow Timeline Layouts"
     await setupTimeline(page, {
       viewport: { width: 420, height: 700 },
+      settings: { timelineDetail: { ...timelinePresets[2].value, notices: { placement: "separate" } } },
       sessionMessages: [
         {
           id: "msg_model_fast_nano",
diff --git a/packages/app/e2e/regression/session-timeline-reasoning-projection.spec.ts b/packages/app/e2e/regression/session-timeline-reasoning-projection.spec.ts
index ab3cfed6d0b..114ae780287 100644
--- a/packages/app/e2e/regression/session-timeline-reasoning-projection.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-reasoning-projection.spec.ts
@@ -5,134 +5,48 @@ import {
   reasoningPart,
   setupTimeline,
   textPart,
-  toolPart,
   userMessage,
 } from "../performance/timeline-stability/fixture"
 
-test("changes live reasoning through Settings and persists Hidden, Compact, and Full", async ({ page }) => {
+test("changes timeline presets and saves custom thinking details", async ({ page }) => {
   await setupTimeline(page, {
     messages: [
       userMessage(),
-      assistantMessage(
-        [
-          reasoningPart(
-            "prt_reasoning_settings",
-            "## Inspecting stability\n\nThe selected mode controls these details.",
-          ),
-        ],
-        { completed: false },
-      ),
+      assistantMessage([
+        reasoningPart("prt_reasoning_settings", "## Inspecting stability\n\nThe selected mode controls these details."),
+      ]),
     ],
   })
   const part = page.locator(`[data-timeline-part-id="${assistantID}:reasoning:0"]`)
-  await expect(part.getByRole("button")).toHaveAttribute("aria-expanded", "false")
   const settings = page.getByTestId("settings-screen")
-  const select = settings.locator('[data-action="settings-reasoning-mode"] [data-component="select-v2"]')
-  for (const label of ["Full", "Hidden", "Compact"] as const) {
-    await page.keyboard.press("Control+,")
-    await expect(settings.getByText("Model reasoning", { exact: true })).toBeVisible()
-    await expect(select).toHaveAttribute("aria-expanded", "false")
-    await select.click()
-    await expect(page.getByRole("listbox").getByRole("option")).toHaveText(["Hidden", "Compact", "Full"])
-    await page.getByRole("option", { name: label, exact: true }).click()
-    await expect(select).toHaveText(label)
-    await expect(select).toHaveAttribute("aria-expanded", "false")
-    await expect
-      .poll(() => page.evaluate(() => JSON.parse(localStorage.getItem("settings.v3") ?? "{}").general?.reasoningMode))
-      .toBe(label.toLowerCase())
-    await settings.getByRole("button", { name: "Back to app", exact: true }).click()
-    await expect(settings).toBeHidden()
-    await expect(page.locator('[data-timeline-row="Thinking"]')).toHaveCount(label === "Hidden" ? 0 : 1)
-    await expect(part).toHaveCount(label === "Hidden" ? 0 : 1)
-    if (label === "Hidden") {
-      await expect(page.getByText("The selected mode controls these details.", { exact: true })).toBeHidden()
-      continue
-    }
-    await expect(part.getByRole("button")).toHaveAttribute("aria-expanded", String(label === "Full"))
-    if (label === "Full")
-      await expect(part.getByText("The selected mode controls these details.", { exact: true })).toBeVisible()
-    if (label === "Compact") {
-      await expect(part.getByRole("button")).toContainText("Inspecting stability")
-      await expect(part.getByText("The selected mode controls these details.", { exact: true })).toBeHidden()
-    }
-  }
   await page.keyboard.press("Control+,")
-  await expect(select).toHaveText("Compact")
-})
-
-// The persisted boolean migrates to compact (false) or full (true).
-for (const summaries of [false, true]) {
-  for (const profile of ["none", "blank", "heading", "tool", "text"] as const) {
-    test(`projects legacy ${summaries ? "full" : "compact"} reasoning with ${profile}`, async ({ page }) => {
-      await setupTimeline(page, {
-        messages: [
-          userMessage(),
-          assistantMessage(
-            [
-              ...(profile === "none"
-                ? []
-                : [
-                    reasoningPart(
-                      `prt_reasoning_${summaries}_${profile}`,
-                      profile === "blank"
-                        ? "   "
-                        : "## Inspecting stability\n\nI will inspect the timeline before changing its state.",
-                    ),
-                  ]),
-              ...(profile === "tool"
-                ? [toolPart(`prt_reasoning_tool_${summaries}`, "skill", "running", { name: "inspect" })]
-                : []),
-              ...(profile === "text" ? [textPart(`prt_reasoning_text_${summaries}`, "The timeline is stable.")] : []),
-            ],
-            { completed: false },
-          ),
-        ],
-        settings: { showReasoningSummaries: summaries },
-      })
-      const part = page.locator(`[data-timeline-part-id="${assistantID}:reasoning:0"]`)
-      await expect(page.locator('[data-timeline-row="Thinking"]')).toHaveCount(
-        profile === "blank" || profile === "heading" ? 1 : 0,
-      )
-      if (profile === "none") {
-        await expect(part).toHaveCount(0)
-        return
-      }
-      if (profile === "blank") {
-        await expect(part).toContainText("Thinking")
-        await expect(part.getByRole("heading")).toHaveCount(0)
-        return
-      }
-      if (profile === "tool") {
-        const group = page.locator('[data-component="collapsed-tool-group"]')
-        const used = group.locator(':scope > [data-component="collapsible"] > [data-slot="collapsible-trigger"]')
-        await expect(used).toHaveText(/^Used\s*1 Skill$/)
-        await expect(used).toHaveAttribute("aria-expanded", "false")
-        await expect(page.getByText("Inspecting stability", { exact: true })).toBeHidden()
-        await expect(used.locator('[data-slot="basic-tool-tool-title"]')).toHaveText("1 Skill")
-        await used.click()
-        await expect(used).toHaveAttribute("aria-expanded", "true")
-        await expect(group.locator(`[data-timeline-part-id="prt_reasoning_tool_${summaries}"]`)).toBeVisible()
-        await expect(group.locator('[data-component="reasoning-part"]')).toHaveCount(1)
-      }
-      if (profile === "text") await expect(page.getByText("The timeline is stable.", { exact: true })).toBeVisible()
-      const trigger = part.locator('[data-slot="collapsible-trigger"]')
-      const body = part.getByText("I will inspect the timeline before changing its state.", { exact: true })
-      await expect(trigger).toContainText(profile === "heading" ? "Thinking" : "Thought")
-      await expect(trigger).toHaveAttribute("aria-expanded", String(summaries))
-      if (!summaries) {
-        await expect(body).toBeHidden()
-        if (profile === "heading") await expect(trigger).toContainText("Inspecting stability")
-        await trigger.click()
-        await expect(trigger).toHaveAttribute("aria-expanded", "true")
-      }
-      await expect(body).toBeVisible()
-      await trigger.click()
-      await expect(trigger).toHaveAttribute("aria-expanded", "false")
-      await expect(body).toBeHidden()
-      if (profile !== "heading") await expect(trigger).not.toContainText("Inspecting stability")
-    })
+  const slider = settings.getByRole("slider", { name: "Timeline detail", exact: true })
+  await expect(slider).toBeEnabled()
+  await slider.press("Home")
+  for (const [index, name] of ["Everything", "Detailed", "Compact", "Quiet", "Text only"].entries()) {
+    if (index) await slider.press("ArrowRight")
+    await expect(slider).toHaveValue(String(index))
+    await expect(slider).toHaveAttribute("aria-valuetext", name)
   }
-}
+  await slider.press("Home")
+  await settings.getByRole("button", { name: "Advanced", exact: true }).click()
+  await settings.getByRole("button", { name: "Thinking Placement Separate", exact: true }).click()
+  await page.getByRole("option", { name: "Grouped", exact: true }).click()
+  await settings.getByRole("button", { name: "Thinking Details Expanded", exact: true }).click()
+  await page.getByRole("option", { name: "Collapsed", exact: true }).click()
+  await expect(slider).toHaveAttribute("aria-valuetext", "Custom")
+  await expect
+    .poll(() =>
+      page.evaluate(() => JSON.parse(localStorage.getItem("settings.v3") ?? "{}").general?.timelineDetail?.thinking),
+    )
+    .toEqual({ placement: "grouped", details: "collapsed" })
+  await settings.getByRole("button", { name: "Back to app", exact: true }).click()
+  await expect(settings).toBeHidden()
+  await page.getByRole("button", { name: "Reasoning", exact: true }).click()
+  await expect(part.getByRole("button")).toHaveAttribute("aria-expanded", "false")
+  await part.getByRole("button").click()
+  await expect(part.getByText("The selected mode controls these details.", { exact: true })).toBeVisible()
+})
 
 test("does not infer reasoning visibility from provider identity", async ({ page }) => {
   await setupTimeline(page, {
diff --git a/packages/app/e2e/regression/session-timeline-reducer-projection.spec.ts b/packages/app/e2e/regression/session-timeline-reducer-projection.spec.ts
index 548a8777696..283b2d57db8 100644
--- a/packages/app/e2e/regression/session-timeline-reducer-projection.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-reducer-projection.spec.ts
@@ -18,10 +18,10 @@ test("reducer-hardening: converges when idle arrives before final part and messa
   const textID = "prt_event_order_text"
   const assistant = assistantMessage([textPart(textID, "Partial")], { completed: false })
   const timeline = await setupTimeline(page, { messages: [userMessage(), assistant] })
-  await timeline.send(status("busy"), 100)
-  await timeline.send(status("idle"), 100)
-  await timeline.send(partUpdated(textPart(textID, "Final after early idle")), 120)
-  await timeline.send(messageUpdated(completedAssistantInfo(assistant)), 250)
+  await timeline.send(status("busy"))
+  await timeline.send(status("idle"))
+  await timeline.send(partUpdated(textPart(textID, "Final after early idle")))
+  await timeline.send(messageUpdated(completedAssistantInfo(assistant)))
 
   await expect(page.locator('[data-timeline-row="Thinking"]')).toHaveCount(0)
   await expect(page.locator(`[data-timeline-part-id="${renderedPartID(textID)}"]`)).toContainText(
@@ -138,7 +138,7 @@ test("combines follow-up patches into one three-file stack inside Used", async (
   await expect(group.locator('[data-slot="apply-patch-filename"]')).toHaveText(["a.ts", "b.ts", "c.ts"])
 })
 
-test("keeps failed search calls and their error cards inside the collapsed stack", async ({ page }) => {
+test("keeps failed search calls and their error cards outside the collapsed stack", async ({ page }) => {
   const parts = [
     toolPart(
       "prt_error_glob",
@@ -161,12 +161,9 @@ test("keeps failed search calls and their error cards inside the collapsed stack
   ]
   await setupTimeline(page, { messages: [userMessage(), assistantMessage(parts)] })
 
-  const group = page.locator('[data-timeline-part-ids="prt_error_glob,prt_error_grep"]')
-  const summary = group.getByRole("button", { name: "Used 1 Glob, 1 Grep", exact: true })
-  await expect(summary.locator('[data-slot="basic-tool-tool-title"]')).toHaveText("1 Glob, 1 Grep")
-  await summary.click()
-  await expect(group.locator('[data-kind="tool-error-card"]')).toHaveCount(2)
-  const glob = group.locator('[data-timeline-part-id="prt_error_glob"]')
+  await expect(page.locator('[data-component="collapsed-tool-group"]')).toHaveCount(0)
+  await expect(page.locator('[data-kind="tool-error-card"]')).toHaveCount(2)
+  const glob = page.locator('[data-timeline-part-id="prt_error_glob"]')
   await expect(glob).toContainText("Invalid tool input")
   await expect(glob.locator('[data-component="tool-error-card-icon"]')).toBeVisible()
   await expect(glob.locator('[data-component="tool-error-card-icon"] use')).toHaveAttribute(
@@ -180,7 +177,7 @@ test("keeps failed search calls and their error cards inside the collapsed stack
         .evaluate((element) => getComputedStyle(element, "::before").display),
     )
     .toBe("none")
-  await expect(group.locator('[data-timeline-part-id="prt_error_grep"]')).toContainText(
+  await expect(page.locator('[data-timeline-part-id="prt_error_grep"]')).toContainText(
     "Search timed out after 30 seconds",
   )
 })
diff --git a/packages/app/e2e/regression/session-timeline-shell-outline.spec.ts b/packages/app/e2e/regression/session-timeline-shell-outline.spec.ts
index 07fc720470d..cc09a4348bb 100644
--- a/packages/app/e2e/regression/session-timeline-shell-outline.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-shell-outline.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test, type Locator, type Page } from "@playwright/test"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import {
   assistantMessage,
   setupTimeline,
@@ -74,21 +75,29 @@ test("keeps the patch card inside a fractionally short virtual row", async ({ pa
     additions: 1,
     deletions: 1,
   }
-  const timeline = await setupTimeline(page, {
+  await setupTimeline(page, {
     messages: [
       userMessage(),
       assistantMessage([
-        toolPart(patchID, "patch", "completed", { patchText: "Update src/outline.ts" }, { metadata: { files: [file] } }),
+        toolPart(
+          patchID,
+          "patch",
+          "completed",
+          { patchText: "Update src/outline.ts" },
+          { metadata: { files: [file] } },
+        ),
       ]),
     ],
-    settings: { editToolPartsExpanded: true },
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, edit: { placement: "separate", details: "collapsed" } },
+    },
     reducedMotion: true,
   })
   const part = page.locator(`[data-timeline-part-id="${patchID}"]`)
   const card = part.locator('[data-component="accordion"][data-scope="apply-patch"]')
   const row = page.locator("[data-timeline-key]", { has: part })
   await expect(card).toBeVisible()
-  await timeline.settle()
+  await expect(card.getByRole("button")).toHaveAttribute("aria-expanded", "false")
 
   const geometry = await row.evaluate((element) => {
     const card = element.querySelector<HTMLElement>('[data-component="accordion"][data-scope="apply-patch"]')
@@ -106,8 +115,6 @@ test("keeps the patch card inside a fractionally short virtual row", async ({ pa
       cardHeight: cardRect.height,
     }
   })
-  await timeline.settle()
-
   expect(geometry.overflow).toBeCloseTo(0.49, 1)
   expect(geometry.paintOverflow).toBeLessThanOrEqual(0)
   const edges = await captureCardEdges(page, card)
diff --git a/packages/app/e2e/regression/session-timeline-tool-projection.spec.ts b/packages/app/e2e/regression/session-timeline-tool-projection.spec.ts
index d723c973c42..1a6f323941a 100644
--- a/packages/app/e2e/regression/session-timeline-tool-projection.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-tool-projection.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import {
   assistantMessage,
   partUpdated,
@@ -11,7 +12,9 @@ test("transitions shell and question through running error outcomes", async ({ p
   const shellID = "prt_transition_error_shell"
   const questionID = "prt_transition_error_question"
   const timeline = await setupTimeline(page, {
-    settings: { shellToolPartsExpanded: true },
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, shell: { placement: "separate", details: "expanded" } },
+    },
     messages: [
       userMessage(),
       assistantMessage(
@@ -24,18 +27,17 @@ test("transitions shell and question through running error outcomes", async ({ p
     ],
   })
   await expect(page.locator(`[data-timeline-part-id="${questionID}"]`)).toHaveCount(0)
-  await timeline.send(partUpdated(toolPart(shellID, "shell", "running", { command: "exit 1" })), 120)
-  await timeline.send(partUpdated(toolPart(questionID, "question", "running", questionInput())), 180)
+  await timeline.send(partUpdated(toolPart(shellID, "shell", "running", { command: "exit 1" })))
+  await expect(page.locator(`[data-timeline-part-id="${shellID}"]`)).toContainText("exit 1")
+  await timeline.send(partUpdated(toolPart(questionID, "question", "running", questionInput())))
   await expect(page.locator(`[data-timeline-part-id="${questionID}"]`)).toHaveCount(0)
   await timeline.send(
     partUpdated(toolPart(shellID, "shell", "error", { command: "exit 1" }, { error: "Command exited 1" })),
-    180,
   )
   await timeline.send(
     partUpdated(
       toolPart(questionID, "question", "error", questionInput(), { error: "The user dismissed this question" }),
     ),
-    250,
   )
 
   await expect(page.locator(`[data-timeline-part-id="${shellID}"] [data-kind="tool-error-card"]`)).toBeVisible()
@@ -46,7 +48,9 @@ test("preserves surviving grouped patch state when its first patch fails", async
   const failed = "prt_grouped_patch_failed"
   const surviving = "prt_grouped_patch_surviving"
   const timeline = await setupTimeline(page, {
-    settings: { editToolPartsExpanded: true },
+    settings: {
+      timelineDetail: { ...timelinePresets[2].value, edit: { placement: "separate", details: "collapsed" } },
+    },
     messages: [
       userMessage(),
       assistantMessage(
@@ -80,6 +84,7 @@ test("preserves surviving grouped patch state when its first patch fails", async
   const group = page.locator(`[data-timeline-part-ids="${failed},${surviving}"]`)
   const file = group.locator('[data-scope="apply-patch"] button')
   await expect(file).toBeVisible()
+  await expect(file).toHaveAttribute("aria-expanded", "false")
   await file.click()
   await expect(file).toHaveAttribute("aria-expanded", "true")
   await group.evaluate((element) => {
@@ -116,6 +121,7 @@ test("preserves surviving grouped patch state when its first patch fails", async
 test("groups instruction files loaded by the same read", async ({ page }) => {
   const id = "prt_read_instructions"
   await setupTimeline(page, {
+    settings: { timelineDetail: { ...timelinePresets[2].value, tools: { placement: "separate" } } },
     messages: [
       userMessage(),
       assistantMessage([
@@ -148,7 +154,10 @@ test("groups only consecutive successful skill tools", async ({ page }) => {
     toolPart("prt_skill_break", "read", "completed", { path: "src/a.ts" }),
     toolPart("prt_skill_last", "skill", "completed", { id: "opencode" }),
   ]
-  await setupTimeline(page, { messages: [userMessage(), assistantMessage(parts)] })
+  await setupTimeline(page, {
+    settings: { timelineDetail: timelinePresets[2].value },
+    messages: [userMessage(), assistantMessage(parts)],
+  })
 
   const group = page.locator(`[data-timeline-part-ids="${parts.map((part) => part.id).join(",")}"]`)
   await group.getByRole("button").click()
diff --git a/packages/app/e2e/regression/session-timeline-working.spec.ts b/packages/app/e2e/regression/session-timeline-working.spec.ts
index c2e0fa044d2..17e0cd0df67 100644
--- a/packages/app/e2e/regression/session-timeline-working.spec.ts
+++ b/packages/app/e2e/regression/session-timeline-working.spec.ts
@@ -1,4 +1,5 @@
 import { expect, test } from "@playwright/test"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import {
   assistantID,
   assistantMessage,
@@ -19,6 +20,9 @@ for (const width of [1400, 390]) {
       messages: [userMessage()],
       sessionStatus: { [sessionID]: { type: "busy" } },
       viewport: { width, height: 900 },
+      settings: {
+        timelineDetail: { ...timelinePresets[2].value, thinking: { placement: "separate", details: "collapsed" } },
+      },
     })
     const working = page.locator('[data-component="session-working"]')
     await expect(working).toHaveCount(1)
@@ -51,7 +55,9 @@ for (const name of ["shell", "patch", "subagent"] as const) {
   test(`hides Working during ${name} input and execution, then restores it on completion`, async ({ page }) => {
     const timeline = await setupTimeline(page, {
       messages: [userMessage(), assistantMessage([], { completed: false })],
-      settings: { editToolPartsExpanded: true },
+      settings: {
+        timelineDetail: { ...timelinePresets[0].value, shell: { placement: "separate", details: "collapsed" } },
+      },
     })
     const working = page.locator('[data-component="session-working"]')
     await expect(working).toBeVisible()
@@ -89,13 +95,8 @@ for (const name of ["shell", "patch", "subagent"] as const) {
     await expect(working).toHaveCount(0)
 
     await timeline.send(partUpdated(toolPart(id, name, "completed", input, { metadata })))
-    if (name === "shell") {
-      const group = page.locator('[data-component="collapsed-tool-group"]')
-      await expect(
-        group.getByRole("button", { name: "Used 1 Shell", exact: true, includeHidden: true }),
-      ).toHaveAttribute("aria-expanded", "false")
-      await expect(group).toBeVisible()
-    }
+    await expect(tool).toBeVisible()
+    await expect(page.locator('[data-component="collapsed-tool-group"]')).toHaveCount(0)
     await expect(working.locator('[data-component="text-shimmer"]')).toHaveAttribute("aria-label", "Working")
     await expect(working).toBeVisible()
     await expect(working.locator('[data-component="text-shimmer"]')).toHaveAttribute("data-active", "true")
@@ -259,6 +260,7 @@ for (const failed of [false, true]) {
     const editor = page.locator('[data-component="composer"]').getByRole("textbox")
     await expect(editor).toBeEditable()
     await editor.fill("Check the working indicator immediately.")
+    await expect(page.locator('[data-action="composer-submit"]')).toBeEnabled()
     const requested = page.waitForRequest(
       (request) =>
         request.method() === "POST" && new URL(request.url()).pathname === `/api/session/${sessionID}/prompt`,
diff --git a/packages/app/src/runtime/i18n/en.ts b/packages/app/src/runtime/i18n/en.ts
index fe644ac5f13..91f3ddc0975 100644
--- a/packages/app/src/runtime/i18n/en.ts
+++ b/packages/app/src/runtime/i18n/en.ts
@@ -951,6 +951,41 @@ export const dict = {
   "settings.general.section.feed": "Feed",
   "settings.general.section.display": "Display",
 
+  "settings.timeline.title": "Timeline",
+  "settings.timeline.detail": "Timeline detail",
+  "settings.timeline.description": "Choose how much activity appears in the timeline. Messages stay visible.",
+  "settings.timeline.preset.everything": "Everything",
+  "settings.timeline.preset.detailed": "Detailed",
+  "settings.timeline.preset.compact": "Compact",
+  "settings.timeline.preset.quiet": "Quiet",
+  "settings.timeline.preset.text-only": "Text only",
+  "settings.timeline.description.everything": "Show all activity separately. Expand shell output, edits, and thinking.",
+  "settings.timeline.description.detailed":
+    "Expand shell output and edits. Show subagents separately and group other activity in Used.",
+  "settings.timeline.description.compact": "Group all activity in Used with details collapsed.",
+  "settings.timeline.description.quiet": "Group edits and subagents in Used. Hide other activity.",
+  "settings.timeline.description.text-only": "Hide all activity. Show only messages.",
+  "settings.timeline.description.custom": "Use your selected placement and details for each activity category.",
+  "settings.timeline.custom": "Custom",
+  "settings.timeline.advanced": "Advanced",
+  "settings.timeline.advanced.description": "Set placement and details for each activity category.",
+  "settings.timeline.advanced.explainer": "Grouped activity goes into Used. Details applies after opening the group.",
+  "settings.timeline.activity": "Activity",
+  "settings.timeline.category.shell": "Shell",
+  "settings.timeline.category.edit": "Edits",
+  "settings.timeline.category.thinking": "Thinking",
+  "settings.timeline.category.subagents": "Subagents",
+  "settings.timeline.category.notices": "Notices",
+  "settings.timeline.category.tools": "Other tools",
+  "settings.timeline.placement.title": "Placement",
+  "settings.timeline.placement.separate": "Separate",
+  "settings.timeline.placement.grouped": "Grouped",
+  "settings.timeline.placement.hidden": "Hidden",
+  "settings.timeline.expansion.title": "Details",
+  "settings.timeline.expansion.collapsed": "Collapsed",
+  "settings.timeline.expansion.expanded": "Expanded",
+  "settings.timeline.running": "Running",
+
   "settings.general.row.language.title": "Language",
   "settings.general.row.language.description": "Change the display language for OpenCode",
   "settings.general.row.shell.title": "Terminal shell",
diff --git a/packages/app/src/session/timeline/controller-projection.test.ts b/packages/app/src/session/timeline/controller-projection.test.ts
index 771683302e2..27f514e74ed 100644
--- a/packages/app/src/session/timeline/controller-projection.test.ts
+++ b/packages/app/src/session/timeline/controller-projection.test.ts
@@ -3,6 +3,7 @@ import type { SessionInboxInfo, SessionMessageInfo } from "@opencode-ai/client/p
 import { createRoot } from "solid-js"
 import { applyTimelineMessageHandoff, visibleTimelineMessages } from "./controller-projection"
 import { createTimelineProjection } from "./projection"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 
 const messages = [
   { id: "msg_1", type: "user", text: "first", time: { created: 1 } },
@@ -63,6 +64,7 @@ describe("visibleTimelineMessages", () => {
         reasoningMode: () => "compact",
         shellToolDefaultOpen: () => false,
         editToolDefaultOpen: () => false,
+        timelineDetail: () => timelinePresets[2].value,
         pendingUserMessageIDs: () => new Set([steer.id]),
       })
       expect(projection.activeMessageID()).toBe("msg_1")
diff --git a/packages/app/src/session/timeline/controller.tsx b/packages/app/src/session/timeline/controller.tsx
index e4bff43cde6..ca9555c6164 100644
--- a/packages/app/src/session/timeline/controller.tsx
+++ b/packages/app/src/session/timeline/controller.tsx
@@ -21,6 +21,7 @@ import { applyTimelineMessageHandoff, timelineChildTitle, visibleTimelineMessage
 import { createTimelineProjection } from "./projection"
 import { useServer } from "@/runtime/server/current"
 import { getSessionMessageHandoff } from "@/session/handoff"
+import type { ReasoningMode } from "@opencode-ai/session-ui/timeline/projection"
 
 const emptyMessages: SessionMessageInfo[] = []
 const taskDescription = (message: SessionMessageInfo, sessionID: string): string | undefined => {
@@ -101,12 +102,32 @@ export function createTimelineController(input: { session: TimelineSessionSource
     })
   })
   const showHeader = createMemo(() => !!input.session.identity.sessionID())
+  const timelineDetail = createMemo(() => {
+    const detail = settings.general.timelineDetail()
+    return {
+      shell: { ...detail.shell },
+      edit: { ...detail.edit },
+      thinking: { ...detail.thinking },
+      subagents: { ...detail.subagents },
+      notices: { ...detail.notices },
+      tools: { ...detail.tools },
+    }
+  })
+  const reasoningMode = (): ReasoningMode =>
+    timelineDetail().thinking.placement === "hidden"
+      ? "hidden"
+      : timelineDetail().thinking.details === "expanded"
+        ? "full"
+        : "compact"
+  const shellToolPartsExpanded = () => timelineDetail().shell.details === "expanded"
+  const editToolPartsExpanded = () => timelineDetail().edit.details === "expanded"
   const projection = createTimelineProjection({
     sessionMessages: projectedMessages,
     status: input.session.data.status,
-    reasoningMode: settings.general.reasoningMode,
-    shellToolDefaultOpen: settings.general.shellToolPartsExpanded,
-    editToolDefaultOpen: settings.general.editToolPartsExpanded,
+    reasoningMode,
+    shellToolDefaultOpen: shellToolPartsExpanded,
+    editToolDefaultOpen: editToolPartsExpanded,
+    timelineDetail,
     pendingUserMessageIDs,
   })
   const [pending, setPending] = createStore({ rename: false })
@@ -235,9 +256,10 @@ export function createTimelineController(input: { session: TimelineSessionSource
       childTitle,
       showHeader,
       projection,
-      reasoningMode: settings.general.reasoningMode,
-      shellToolPartsExpanded: settings.general.shellToolPartsExpanded,
-      editToolPartsExpanded: settings.general.editToolPartsExpanded,
+      timelineDetail,
+      reasoningMode,
+      shellToolPartsExpanded,
+      editToolPartsExpanded,
     },
     pending: {
       rename: () => pending.rename,
diff --git a/packages/app/src/session/timeline/message-timeline.tsx b/packages/app/src/session/timeline/message-timeline.tsx
index f0a56539d3c..4af78317b9e 100644
--- a/packages/app/src/session/timeline/message-timeline.tsx
+++ b/packages/app/src/session/timeline/message-timeline.tsx
@@ -33,6 +33,7 @@ import { useCommand } from "@/shell/commands/command"
 import { useSettings } from "@/settings/model"
 import { SessionTitleHeader } from "../session-identity-header"
 import { SessionHeader } from "@/session/header/session-header"
+import { SessionProgressIndicatorV2 } from "@opencode-ai/session-ui/v2/session-progress-indicator-v2"
 
 type BackgroundTask = {
   id: string
@@ -420,6 +421,7 @@ function MessageTimelineView(
   const messageByID = projection.messageByID
   const virtualized = createTimelineVirtualizer({
     sessionKey: () => `${server.key}/${props.data.sessionID()}`,
+    presentationKey: () => JSON.stringify(props.data.timelineDetail()),
     projection,
     showHeader,
     pinned,
@@ -527,6 +529,7 @@ function MessageTimelineView(
     reasoningMode: props.data.reasoningMode,
     shellToolDefaultOpen: props.data.shellToolPartsExpanded,
     editToolDefaultOpen: props.data.editToolPartsExpanded,
+    timelineDetail: props.data.timelineDetail,
     disclosure: virtualized.disclosure,
     centered: () => props.centered,
     padding: turnPadding,
@@ -632,6 +635,28 @@ function MessageTimelineView(
               </div>
             </div>
           </Show>
+          <Show
+            when={
+              !showWorking() &&
+              !backgroundHintPresence.present() &&
+              props.background
+                .tasks()
+                .some(
+                  (task) =>
+                    props.data.timelineDetail()[task.type === "subagent" ? "subagents" : "shell"].placement !==
+                    "separate",
+                )
+            }
+          >
+            <div
+              role="status"
+              class={`flex h-9 w-full min-w-0 items-center gap-2 pt-3 text-13-regular text-v2-text-text-muted ${turnPadding()}`}
+              classList={{ "md:max-w-[1000px] md:mx-auto": props.centered }}
+            >
+              <SessionProgressIndicatorV2 />
+              <span>{language.t("settings.timeline.running")}</span>
+            </div>
+          </Show>
         </>
       }
       deferred={(row) => {
diff --git a/packages/app/src/session/timeline/virtualizer.tsx b/packages/app/src/session/timeline/virtualizer.tsx
index d27bfcd8221..235fba7fdbb 100644
--- a/packages/app/src/session/timeline/virtualizer.tsx
+++ b/packages/app/src/session/timeline/virtualizer.tsx
@@ -21,7 +21,7 @@ import {
   type Accessor,
   type JSX,
 } from "solid-js"
-import { createStore } from "solid-js/store"
+import { createStore, reconcile } from "solid-js/store"
 import { createMediaQuery } from "@solid-primitives/media"
 import type { createTimelineProjection } from "./projection"
 import { observeElementOffsetReconnectAware } from "./observe-element-offset"
@@ -33,7 +33,15 @@ const pendingMarkdown = '[data-component="markdown"]:not([data-markdown-ready])'
 // exactly to the end, while a one-pixel nudge upward is a deliberate move away from it.
 const endEpsilon = 0.5
 const upwardKeys = new Set(["up", "page-up", "home"])
-const cache = new Map<string, { measurements: VirtualItem[]; toolOpen: Record<string, boolean | undefined> }>()
+const cache = new Map<
+  string,
+  {
+    measurements: VirtualItem[]
+    toolOpen: Record<string, boolean | undefined>
+    patchGroupKeys: Map<string, string>
+    presentationKey?: string
+  }
+>()
 
 type Projection = Pick<
   ReturnType<typeof createTimelineProjection>,
@@ -42,6 +50,7 @@ type Projection = Pick<
 
 type Input = {
   sessionKey: Accessor<string>
+  presentationKey?: Accessor<string>
   projection: Projection
   showHeader: Accessor<boolean>
   /** True while the timeline follows the newest content. Drives every anchoring decision. */
@@ -77,11 +86,20 @@ export function createTimelineVirtualizer(input: Input) {
   const isDesktop = createMediaQuery("(min-width: 768px)")
   const topOffset = () => (input.showHeader() ? 64 : isDesktop() ? 0 : 16)
   const ownerSessionKey = input.sessionKey()
-  const cached = cache.get(ownerSessionKey)
+  const entry = cache.get(ownerSessionKey)
+  const cached = entry?.presentationKey === input.presentationKey?.() ? entry : undefined
   const initialMeasurements = cached?.measurements
   const coldBottomMount = !initialMeasurements?.length && input.pinned()
   const [listRoot, setListRoot] = createSignal<HTMLDivElement>()
   const [toolOpen, setToolOpen] = createStore<Record<string, boolean | undefined>>(cached?.toolOpen ?? {})
+  const patchGroupKeys = cached?.patchGroupKeys ?? new Map<string, string>()
+  createEffect(
+    on(
+      () => input.presentationKey?.(),
+      () => setToolOpen(reconcile({})),
+      { defer: true },
+    ),
+  )
   const [rendering, setRendering] = createStore({ initialTail: coldBottomMount })
   const rows = input.projection.rows
   const rowByKey = input.projection.rowByKey
@@ -189,7 +207,8 @@ export function createTimelineVirtualizer(input: Input) {
     },
     scrollEndThreshold: 80,
     get scrollMargin() {
-      return topOffset()
+      // Empty projections still need the bottom spacer for running status.
+      return rows().length > 0 ? topOffset() : 0
     },
     paddingEnd: 64,
     get rangeExtractor() {
@@ -540,15 +559,13 @@ export function createTimelineVirtualizer(input: Input) {
             }}
           >
             <For each={virtualRowKeys()}>{(rowKey) => <VirtualRow rowKey={rowKey} />}</For>
-            <Show when={rows().length > 0}>
-              <div
-                data-timeline-row="bottom-spacer"
-                class="h-16 absolute top-0 left-0 w-full"
-                style={{ transform: `translateY(${virtualizer.getTotalSize() - 64}px)` }}
-              >
-                {props.bottomSpacer}
-              </div>
-            </Show>
+            <div
+              data-timeline-row="bottom-spacer"
+              class="h-16 absolute top-0 left-0 w-full"
+              style={{ transform: `translateY(${virtualizer.getTotalSize() - 64}px)` }}
+            >
+              {props.bottomSpacer}
+            </div>
           </div>
         </ScrollView>
       </div>
@@ -557,7 +574,12 @@ export function createTimelineVirtualizer(input: Input) {
 
   onCleanup(() => {
     cache.delete(ownerSessionKey)
-    cache.set(ownerSessionKey, { measurements: virtualizer.takeSnapshot(), toolOpen: { ...toolOpen } })
+    cache.set(ownerSessionKey, {
+      measurements: virtualizer.takeSnapshot(),
+      toolOpen: { ...toolOpen },
+      patchGroupKeys,
+      presentationKey: input.presentationKey?.(),
+    })
     while (cache.size > 16) cache.delete(cache.keys().next().value!)
     coldPending = false
     contentObserver?.disconnect()
@@ -569,6 +591,7 @@ export function createTimelineVirtualizer(input: Input) {
 
   return {
     disclosure: {
+      patchGroupKeys,
       value: (key: string) => toolOpen[key],
       set: (key: string, open: boolean) => setToolOpen(key, open),
     },
diff --git a/packages/app/src/settings/general/general.tsx b/packages/app/src/settings/general/general.tsx
index b9d5495b505..e291e65c839 100644
--- a/packages/app/src/settings/general/general.tsx
+++ b/packages/app/src/settings/general/general.tsx
@@ -4,7 +4,7 @@ import { Button } from "@opencode-ai/ui/button"
 import { Select } from "@opencode-ai/ui/select"
 import { Switch } from "@opencode-ai/ui/switch"
 import { TextInput } from "@opencode-ai/ui/text-input"
-import type { ReasoningMode } from "@opencode-ai/session-ui/timeline/projection"
+import { TimelineDetailControl } from "@/settings/timeline-detail"
 import { useLanguage } from "@/runtime/i18n/language"
 import { usePlatform } from "@/runtime/platform/platform"
 import { useUpdaterAction } from "@/shell/updates/action"
@@ -184,34 +184,6 @@ const FollowUpBehaviorSetting: Component = () => {
   )
 }
 
-const ReasoningModeSetting: Component = () => {
-  const language = useLanguage()
-  const settings = useSettings()
-  const options = createMemo((): { value: ReasoningMode; label: string }[] => [
-    { value: "hidden", label: language.t("settings.general.row.reasoningMode.hidden") },
-    { value: "compact", label: language.t("settings.general.row.reasoningMode.compact") },
-    { value: "full", label: language.t("settings.general.row.reasoningMode.full") },
-  ])
-
-  return (
-    <SettingsRow
-      title={language.t("settings.general.row.reasoningMode.title")}
-      description={language.t("settings.general.row.reasoningMode.description")}
-    >
-      <Select
-        data-action="settings-reasoning-mode"
-        options={options()}
-        current={options().find((option) => option.value === settings.general.reasoningMode())}
-        value={(option) => option.value}
-        label={(option) => option.label}
-        placement="bottom-end"
-        gutter={6}
-        onSelect={(option) => option && settings.general.setReasoningMode(option.value)}
-      />
-    </SettingsRow>
-  )
-}
-
 const AppearanceSection: Component<{ controller: AppearanceSettingsController }> = (props) => {
   const language = useLanguage()
   return (
@@ -360,8 +332,6 @@ export const SettingsGeneral: Component<{
         <TerminalPlacementSetting />
         <FollowUpBehaviorSetting />
 
-        <ReasoningModeSetting />
-
         <SettingsRow
           title={language.t("session.review.wrapLines")}
           description={language.t("settings.general.row.mobileDiffWrap.description")}
@@ -378,30 +348,6 @@ export const SettingsGeneral: Component<{
           </div>
         </SettingsRow>
 
-        <SettingsRow
-          title={language.t("settings.general.row.shellToolPartsExpanded.title")}
-          description={language.t("settings.general.row.shellToolPartsExpanded.description")}
-        >
-          <div data-action="settings-feed-shell-tool-parts-expanded">
-            <Switch
-              checked={settings.general.shellToolPartsExpanded()}
-              onChange={(checked) => settings.general.setShellToolPartsExpanded(checked)}
-            />
-          </div>
-        </SettingsRow>
-
-        <SettingsRow
-          title={language.t("settings.general.row.editToolPartsExpanded.title")}
-          description={language.t("settings.general.row.editToolPartsExpanded.description")}
-        >
-          <div data-action="settings-feed-edit-tool-parts-expanded">
-            <Switch
-              checked={settings.general.editToolPartsExpanded()}
-              onChange={(checked) => settings.general.setEditToolPartsExpanded(checked)}
-            />
-          </div>
-        </SettingsRow>
-
         <Show when={import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"}>
           <SettingsRow
             title={language.t("settings.general.row.showProjectIcon.title")}
@@ -585,6 +531,18 @@ export const SettingsGeneral: Component<{
       <div class="settings-tab-body">
         <GeneralSection />
 
+        <section class="settings-section" aria-label={language.t("settings.timeline.title")}>
+          <h3 class="settings-section-title">{language.t("settings.timeline.title")}</h3>
+          <SettingsList>
+            <div class="py-5">
+              <TimelineDetailControl
+                value={settings.general.timelineDetail()}
+                onChange={settings.general.setTimelineDetail}
+              />
+            </div>
+          </SettingsList>
+        </section>
+
         <Show when={desktop()}>
           <UpdatesSection />
         </Show>
diff --git a/packages/app/src/settings/model.test.ts b/packages/app/src/settings/model.test.ts
index a3244a4e94a..fe18b09132d 100644
--- a/packages/app/src/settings/model.test.ts
+++ b/packages/app/src/settings/model.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, test } from "bun:test"
 import { Schema } from "effect"
+import { timelinePresets } from "@opencode-ai/session-ui/timeline/detail"
 import { Persistence } from "@/runtime/persistence/schema"
 import {
   settingsSchema,
@@ -16,54 +17,19 @@ const schema = Persistence.withInitial(settingsPersistence, defaultSettings)
 const decode = Schema.decodeUnknownSync(schema)
 const encode = Schema.encodeSync(schema)
 
-describe("settings reasoning mode migration", () => {
-  test.each([
-    [true, "full"],
-    [false, "compact"],
-  ] as const)("maps persisted reasoning summaries %s to %s", (showReasoningSummaries, reasoningMode) => {
-    const value = { general: { showReasoningSummaries, showTerminal: true }, appearance: { fontSize: 16 } }
-    const settings = decode(value)
-    expect(settings.general.reasoningMode).toBe(reasoningMode)
-    expect(settings.general.showTerminal).toBe(true)
+describe("settings timeline detail migration", () => {
+  test("migrates saved switches and round trips the current settings", () => {
+    const settings = decode({
+      general: { shellToolPartsExpanded: true, editToolPartsExpanded: false, showReasoningSummaries: true },
+      appearance: { fontSize: 16 },
+    })
+    expect(settings.general.timelineDetail).toEqual({
+      ...timelinePresets[2].value,
+      shell: { placement: "separate", details: "expanded" },
+      thinking: { placement: "separate", details: "expanded" },
+    })
     expect(settings.appearance.fontSize).toBe(16)
-    expect(settings.general).not.toHaveProperty("showReasoningSummaries")
-    expect(value.general).not.toHaveProperty("reasoningMode")
-  })
-
-  test.each(["hidden", "compact", "full"])(
-    "preserves an explicit %s mode over either legacy value",
-    (reasoningMode) => {
-      ;[true, false].forEach((showReasoningSummaries) => {
-        const value = { general: { reasoningMode, showReasoningSummaries } }
-        expect(decode(value).general.reasoningMode).toBe(reasoningMode)
-      })
-    },
-  )
-
-  test.each([undefined, null, {}, { showReasoningSummaries: "true" }])(
-    "defaults invalid or absent legacy settings: %j",
-    (general) => {
-      expect(decode({ general }).general.reasoningMode).toBe("compact")
-    },
-  )
-
-  test("migrates an undefined current mode but defaults an invalid current mode", () => {
-    expect(decode({ general: { reasoningMode: undefined, showReasoningSummaries: true } }).general.reasoningMode).toBe(
-      "full",
-    )
-    expect(decode({ general: { reasoningMode: "invalid", showReasoningSummaries: true } }).general.reasoningMode).toBe(
-      "compact",
-    )
-  })
-
-  test("encodes only the current format and round trips migrated settings", () => {
-    const settings = decode({ general: { showReasoningSummaries: true, obsolete: true }, obsolete: true })
-    const encoded = encode(settings)
-    expect(encoded).toEqual(settings)
-    expect(encoded).not.toHaveProperty("obsolete")
-    expect(encoded).not.toHaveProperty("general.obsolete")
-    expect(encoded).not.toHaveProperty("general.showReasoningSummaries")
-    expect(decode(encoded)).toEqual(settings)
+    expect(decode(encode(settings))).toEqual(settings)
   })
 })
 
@@ -71,13 +37,16 @@ describe("settings schema", () => {
   test("uses the supplied initial values independently of the current schema", () => {
     const initial = {
       ...defaultSettings,
-      general: { ...defaultSettings.general, reasoningMode: "hidden" as const, autoSave: false },
+      general: { ...defaultSettings.general, timelineDetail: timelinePresets[4].value, autoSave: false },
       appearance: { ...defaultSettings.appearance, fontSize: 20 },
     }
     const restore = Schema.decodeUnknownSync(Persistence.withInitial(settingsPersistence, initial))
     expect(restore({})).toEqual(initial)
     expect(restore({ general: { reasoningMode: "invalid", showReasoningSummaries: true } })).toEqual(initial)
-    expect(restore({ general: { showReasoningSummaries: true } }).general.reasoningMode).toBe("full")
+    expect(restore({ general: { showReasoningSummaries: true } }).general.timelineDetail.thinking).toEqual({
+      placement: "separate",
+      details: "expanded",
+    })
     expect(() => Schema.decodeUnknownSync(settingsSchema)({})).toThrow()
   })
 
@@ -92,9 +61,7 @@ describe("settings schema", () => {
         showStatus: false,
         showProjectIcon: false,
         showTerminal: false,
-        reasoningMode: "compact",
-        shellToolPartsExpanded: false,
-        editToolPartsExpanded: false,
+        timelineDetail: timelinePresets[2].value,
         showCustomAgents: false,
         mobileTitlebarPosition: "top",
         mobileDiffWrap: true,
@@ -144,7 +111,7 @@ describe("settings schema", () => {
       showTerminal: true,
       autoSave: false,
       releaseNotes: true,
-      reasoningMode: "compact",
+      timelineDetail: timelinePresets[2].value,
       followUpBehavior: "steer",
     })
     expect(settings.appearance).toEqual({
diff --git a/packages/app/src/settings/model.tsx b/packages/app/src/settings/model.tsx
index 0a0d1d2697b..00b72b95f36 100644
--- a/packages/app/src/settings/model.tsx
+++ b/packages/app/src/settings/model.tsx
@@ -1,8 +1,8 @@
-import { reconcile } from "solid-js/store"
+import { reconcile, unwrap } from "solid-js/store"
 import { createEffect, createMemo } from "solid-js"
 import { Effect, Option, Schema, SchemaGetter } from "effect"
 import { createSimpleContext } from "@opencode-ai/ui/context"
-import type { ReasoningMode } from "@opencode-ai/session-ui/timeline/projection"
+import { timelinePresets, type TimelineCategory, type TimelineDetail } from "@opencode-ai/session-ui/timeline/detail"
 import { persisted } from "@/runtime/persistence/storage"
 import { Persistence } from "@/runtime/persistence/schema"
 import { ScopedKey, type ServerScope } from "@/runtime/server/scope"
@@ -68,7 +68,10 @@ export function terminalFontFamily(font: string | undefined) {
   return stack(font, terminalBase)
 }
 
-const reasoningModeSchema = Schema.Literals(["hidden", "compact", "full"])
+const placementSchema = Schema.Literals(["separate", "grouped", "hidden"])
+const detailsSchema = Schema.Literals(["collapsed", "expanded"])
+const activitySchema = Persistence.struct({ placement: placementSchema, details: detailsSchema })
+const placementOnlySchema = Persistence.struct({ placement: placementSchema })
 
 const generalSchema = Persistence.struct({
   autoSave: Schema.Boolean,
@@ -79,9 +82,14 @@ const generalSchema = Persistence.struct({
   showStatus: Schema.Boolean,
   showProjectIcon: Schema.Boolean,
   showTerminal: Schema.Boolean,
-  reasoningMode: reasoningModeSchema,
-  shellToolPartsExpanded: Schema.Boolean,
-  editToolPartsExpanded: Schema.Boolean,
+  timelineDetail: Persistence.struct({
+    shell: activitySchema,
+    edit: activitySchema,
+    thinking: activitySchema,
+    subagents: placementOnlySchema,
+    notices: placementOnlySchema,
+    tools: placementOnlySchema,
+  }),
   showCustomAgents: Schema.Boolean,
   mobileTitlebarPosition: Schema.Literals(["top", "bottom"]),
   mobileDiffWrap: Schema.Boolean,
@@ -134,25 +142,91 @@ export const settingsSchema = Persistence.struct({
   sounds: soundsSchema,
 })
 
+function storedTimelineCategory(category: TimelineCategory) {
+  return Persistence.optional(
+    Schema.Union([
+      Schema.Struct({
+        placement: Persistence.optional(placementSchema),
+        details: Persistence.optional(detailsSchema),
+      }),
+      Schema.Literals(["expanded", "collapsed", "hidden", "visible"]),
+    ]).pipe(
+      Schema.decode({
+        decode: SchemaGetter.transform((value) => {
+          if (typeof value !== "string") return value
+          return {
+            placement:
+              value === "hidden"
+                ? "hidden"
+                : category === "subagents"
+                  ? "separate"
+                  : category === "tools"
+                    ? "grouped"
+                    : value === "expanded"
+                      ? "separate"
+                      : value === "collapsed"
+                        ? "grouped"
+                        : undefined,
+            details: value === "expanded" ? "expanded" : "collapsed",
+          }
+        }),
+        encode: SchemaGetter.passthrough(),
+      }),
+    ),
+  )
+}
+
+function legacyTimelineActivity(value: boolean | "hidden" | "compact" | "full" | null | undefined) {
+  if (value === undefined || value === null) return
+  const expanded = value === true || value === "full"
+  return {
+    placement: value === "hidden" ? "hidden" : expanded ? "separate" : "grouped",
+    details: expanded ? "expanded" : "collapsed",
+  } as const
+}
+
 export const settingsPersistence = Persistence.migrate(
   settingsSchema,
   Schema.Struct({
     general: Persistence.optional(
       Schema.Struct({
-        reasoningMode: Schema.optional(Schema.Unknown),
+        // Keep invalid explicit values distinct from absent values so legacy preferences cannot replace them.
+        timelineDetail: Schema.optional(
+          Schema.NullOr(
+            Schema.Struct({
+              shell: storedTimelineCategory("shell"),
+              edit: storedTimelineCategory("edit"),
+              thinking: storedTimelineCategory("thinking"),
+              subagents: storedTimelineCategory("subagents"),
+              notices: storedTimelineCategory("notices"),
+              tools: storedTimelineCategory("tools"),
+            }),
+          ),
+        ).pipe(Schema.catchDecoding(() => Effect.succeed(Option.some(null)))),
+        reasoningMode: Schema.optional(Schema.NullOr(Schema.Literals(["hidden", "compact", "full"]))).pipe(
+          Schema.catchDecoding(() => Effect.succeed(Option.some(null))),
+        ),
         showReasoningSummaries: Persistence.optional(Schema.Boolean),
+        shellToolPartsExpanded: Persistence.optional(Schema.Boolean),
+        editToolPartsExpanded: Persistence.optional(Schema.Boolean),
       }),
     ),
   }).pipe(
     Schema.decode({
       decode: SchemaGetter.transform((value) => {
-        if (value.general?.reasoningMode !== undefined || value.general?.showReasoningSummaries === undefined)
-          return value
+        const general = value.general
+        if (!general || general.timelineDetail !== undefined) return value
         return {
           ...value,
           general: {
-            ...value.general,
-            reasoningMode: value.general.showReasoningSummaries ? "full" : "compact",
+            ...general,
+            timelineDetail: {
+              shell: legacyTimelineActivity(general.shellToolPartsExpanded),
+              edit: legacyTimelineActivity(general.editToolPartsExpanded),
+              thinking: legacyTimelineActivity(
+                general.reasoningMode === undefined ? general.showReasoningSummaries : general.reasoningMode,
+              ),
+            },
           },
         }
       }),
@@ -171,9 +245,7 @@ export const defaultSettings: Settings = {
     showStatus: false,
     showProjectIcon: false,
     showTerminal: false,
-    reasoningMode: "compact",
-    shellToolPartsExpanded: false,
-    editToolPartsExpanded: false,
+    timelineDetail: { ...timelinePresets[2].value },
     showCustomAgents: false,
     mobileTitlebarPosition: "top",
     mobileDiffWrap: true,
@@ -256,23 +328,9 @@ export const { use: useSettings, provider: SettingsProvider } = createSimpleCont
         setShowTerminal(value: boolean) {
           setStore("general", "showTerminal", value)
         },
-        reasoningMode: withFallback(() => store.general?.reasoningMode, defaultSettings.general.reasoningMode),
-        setReasoningMode(value: ReasoningMode) {
-          setStore("general", "reasoningMode", value)
-        },
-        shellToolPartsExpanded: withFallback(
-          () => store.general?.shellToolPartsExpanded,
-          defaultSettings.general.shellToolPartsExpanded,
-        ),
-        setShellToolPartsExpanded(value: boolean) {
-          setStore("general", "shellToolPartsExpanded", value)
-        },
-        editToolPartsExpanded: withFallback(
-          () => store.general?.editToolPartsExpanded,
-          defaultSettings.general.editToolPartsExpanded,
-        ),
-        setEditToolPartsExpanded(value: boolean) {
-          setStore("general", "editToolPartsExpanded", value)
+        timelineDetail: withFallback(() => store.general?.timelineDetail, defaultSettings.general.timelineDetail),
+        setTimelineDetail(value: TimelineDetail) {
+          setStore("general", "timelineDetail", structuredClone(unwrap(value)))
         },
         showCustomAgents,
         setShowCustomAgents(value: boolean) {
diff --git a/packages/app/src/settings/timeline-detail.css b/packages/app/src/settings/timeline-detail.css
new file mode 100644
index 00000000000..61273ac5efa
--- /dev/null
+++ b/packages/app/src/settings/timeline-detail.css
@@ -0,0 +1,249 @@
+[data-component="timeline-detail-control"] {
+  display: flex;
+  min-width: 0;
+  flex-direction: column;
+  gap: 8px;
+  color: var(--v2-text-text-base);
+  font-size: 13px;
+  line-height: var(--line-height-base);
+  letter-spacing: -0.04px;
+  container: timeline-detail / inline-size;
+
+  [data-slot="timeline-detail-heading"] {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 12px;
+    min-height: 24px;
+    font-weight: 530;
+    line-height: var(--line-height-compact);
+  }
+
+  [data-slot="timeline-detail-current"] {
+    color: var(--v2-text-text-muted);
+    text-align: end;
+  }
+
+  p {
+    margin: 0;
+    color: var(--v2-text-text-muted);
+  }
+
+  [data-slot="timeline-detail-scale"] {
+    position: relative;
+    height: 28px;
+  }
+
+  [data-slot="timeline-detail-track"] {
+    position: absolute;
+    inset-inline: 8px;
+    top: 12px;
+    height: 4px;
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    border-radius: 2px;
+    background: var(--v2-background-bg-layer-03);
+    pointer-events: none;
+
+    span {
+      width: 4px;
+      height: 4px;
+      border-radius: 50%;
+      background: var(--v2-border-border-strong);
+    }
+  }
+
+  input[type="range"] {
+    appearance: none;
+    position: relative;
+    display: block;
+    width: 100%;
+    height: 28px;
+    margin: 0;
+    background: transparent;
+    cursor: pointer;
+    border-radius: 4px;
+
+    &:focus-visible {
+      outline: 2px solid var(--v2-border-border-focus);
+      outline-offset: 2px;
+    }
+
+    &::-webkit-slider-runnable-track {
+      height: 4px;
+      background: transparent;
+    }
+
+    &::-webkit-slider-thumb {
+      appearance: none;
+      width: 16px;
+      height: 16px;
+      margin-top: -6px;
+      border: 1px solid var(--v2-border-border-base);
+      border-radius: 50%;
+      background: var(--v2-background-bg-base);
+      box-shadow: var(--v2-elevation-button-neutral);
+    }
+
+    &::-moz-range-track {
+      height: 4px;
+      background: transparent;
+    }
+
+    &::-moz-range-thumb {
+      box-sizing: border-box;
+      width: 16px;
+      height: 16px;
+      border: 1px solid var(--v2-border-border-base);
+      border-radius: 50%;
+      background: var(--v2-background-bg-base);
+      box-shadow: var(--v2-elevation-button-neutral);
+    }
+  }
+
+  [data-slot="timeline-detail-advanced"] {
+    margin-top: 4px;
+    padding-top: 8px;
+    border-top: 0.5px solid var(--v2-border-border-base);
+  }
+
+  [data-slot="timeline-detail-advanced"] > [data-slot="collapsible-trigger"] {
+    width: fit-content;
+    height: 28px;
+    align-self: flex-start;
+    gap: 6px;
+    font-size: inherit;
+    font-weight: 530;
+    line-height: var(--line-height-compact);
+    letter-spacing: inherit;
+    color: var(--v2-text-text-muted);
+
+    [data-slot="collapsible-arrow"] {
+      width: 16px;
+    }
+
+    &:focus-visible [data-slot="collapsible-arrow"] {
+      opacity: 1;
+    }
+
+    &:dir(rtl):not([aria-expanded="true"]) [data-slot="collapsible-arrow-icon"] {
+      transform: rotate(90deg);
+    }
+  }
+
+  [data-slot="timeline-detail-categories"] {
+    --timeline-detail-columns: minmax(0, 1fr) 100px 108px;
+    display: flex;
+    flex-direction: column;
+    margin-top: 8px;
+  }
+
+  [data-slot="timeline-detail-explainer"] {
+    margin-bottom: 12px;
+  }
+
+  [data-slot="timeline-detail-field-label"] {
+    display: none;
+  }
+
+  [data-slot="timeline-detail-columns"],
+  [data-slot="timeline-detail-category"] {
+    display: grid;
+    grid-template-columns: var(--timeline-detail-columns);
+    align-items: center;
+    column-gap: 8px;
+    line-height: var(--line-height-compact);
+
+    > span {
+      min-width: 0;
+      overflow-wrap: normal;
+    }
+  }
+
+  [data-slot="timeline-detail-columns"] {
+    min-height: 28px;
+    color: var(--v2-text-text-muted);
+
+    span:not(:first-child) {
+      padding-inline-start: 8px;
+    }
+  }
+
+  [data-slot="timeline-detail-category"] {
+    min-height: 40px;
+    padding-block: 8px;
+    border-bottom: 0.5px solid var(--v2-border-border-base);
+
+    &:last-child {
+      border-bottom: 0;
+    }
+
+    [data-component="select-v2-root"],
+    [data-slot="timeline-detail-placement"],
+    [data-slot="timeline-detail-expansion"] {
+      min-width: 0;
+    }
+
+    [data-component="select-v2-root"][data-field] {
+      width: 100%;
+    }
+
+    [data-component="select-v2"][data-appearance="inline"] {
+      width: 100%;
+    }
+  }
+}
+
+@container timeline-detail (max-width: 250px) {
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-heading"] {
+    flex-wrap: wrap;
+    gap: 4px 8px;
+  }
+
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-current"] {
+    margin-inline-start: auto;
+  }
+
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-columns"] {
+    display: none;
+  }
+
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-category"] {
+    grid-template-columns: minmax(0, 1fr);
+    row-gap: 8px;
+    padding-block: 12px;
+
+    > span {
+      font-weight: 530;
+    }
+  }
+
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-field-label"] {
+    display: block;
+    margin-bottom: 2px;
+    padding-inline-start: 8px;
+    font-size: 12px;
+    line-height: var(--line-height-compact);
+    color: var(--v2-text-text-muted);
+  }
+
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-expansion"]:empty {
+    display: none;
+  }
+}
+
+@container timeline-detail (max-width: 310px) {
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-categories"] {
+    --timeline-detail-columns: minmax(0, 1fr) 90px 96px;
+  }
+
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-columns"],
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-category"] {
+    column-gap: 4px;
+  }
+
+  [data-component="timeline-detail-control"] [data-slot="timeline-detail-category"] {
+    min-height: 48px;
+  }
+}
diff --git a/packages/app/src/settings/timeline-detail.tsx b/packages/app/src/settings/timeline-detail.tsx
new file mode 100644
index 00000000000..4275d20ceae
--- /dev/null
+++ b/packages/app/src/settings/timeline-detail.tsx
@@ -0,0 +1,127 @@
+import { For, Show, createMemo, createUniqueId } from "solid-js"
+import { Collapsible } from "@opencode-ai/ui/collapsible"
+import { Select } from "@opencode-ai/ui/select"
+import {
+  timelineCategories,
+  timelinePreset,
+  timelinePresets,
+  type TimelineDetail,
+  type TimelineExpansion,
+  type TimelinePlacement,
+} from "@opencode-ai/session-ui/timeline/detail"
+import { useLanguage } from "@/runtime/i18n/language"
+import "./timeline-detail.css"
+
+const placements: TimelinePlacement[] = ["separate", "grouped", "hidden"]
+const expansions: TimelineExpansion[] = ["collapsed", "expanded"]
+
+export function TimelineDetailControl(props: { value: TimelineDetail; onChange: (value: TimelineDetail) => void }) {
+  const language = useLanguage()
+  const id = createUniqueId()
+  const preset = createMemo(() => timelinePreset(props.value))
+  const position = () => {
+    const current = preset()
+    return current ? timelinePresets.indexOf(current) : 2
+  }
+  const label = () => {
+    const current = preset()
+    return current ? language.t(`settings.timeline.preset.${current.id}`) : language.t("settings.timeline.custom")
+  }
+
+  return (
+    <div data-component="timeline-detail-control">
+      <div data-slot="timeline-detail-heading">
+        <label for={`${id}-slider`}>{language.t("settings.timeline.detail")}</label>
+        <span data-slot="timeline-detail-current" aria-live="polite">
+          {label()}
+        </span>
+      </div>
+      <p id={`${id}-description`} class="sr-only">
+        {language.t("settings.timeline.description")}
+      </p>
+      <div data-slot="timeline-detail-scale">
+        <div data-slot="timeline-detail-track" aria-hidden="true">
+          <For each={timelinePresets}>{() => <span />}</For>
+        </div>
+        <input
+          id={`${id}-slider`}
+          data-action="settings-timeline-detail"
+          type="range"
+          min="0"
+          max={timelinePresets.length - 1}
+          step="1"
+          value={position()}
+          aria-valuetext={label()}
+          aria-describedby={`${id}-description ${id}-preset-description`}
+          onInput={(event) => props.onChange({ ...timelinePresets[event.currentTarget.valueAsNumber].value })}
+        />
+      </div>
+      <p id={`${id}-preset-description`}>{language.t(`settings.timeline.description.${preset()?.id ?? "custom"}`)}</p>
+      <Collapsible variant="ghost" data-slot="timeline-detail-advanced">
+        <Collapsible.Trigger>
+          <span>{language.t("settings.timeline.advanced")}</span>
+          <Collapsible.Arrow />
+        </Collapsible.Trigger>
+        <Collapsible.Content>
+          <div
+            data-slot="timeline-detail-categories"
+            role="group"
+            aria-label={language.t("settings.timeline.advanced.description")}
+          >
+            <p data-slot="timeline-detail-explainer">{language.t("settings.timeline.advanced.explainer")}</p>
+            <div data-slot="timeline-detail-columns">
+              <span>{language.t("settings.timeline.activity")}</span>
+              <span id={`${id}-placement`}>{language.t("settings.timeline.placement.title")}</span>
+              <span id={`${id}-expansion`}>{language.t("settings.timeline.expansion.title")}</span>
+            </div>
+            <For each={timelineCategories}>
+              {(category) => (
+                <div data-slot="timeline-detail-category" role="group" aria-labelledby={`${id}-${category}`}>
+                  <span id={`${id}-${category}`}>{language.t(`settings.timeline.category.${category}`)}</span>
+                  <div data-slot="timeline-detail-placement">
+                    <span data-slot="timeline-detail-field-label" aria-hidden="true">
+                      {language.t("settings.timeline.placement.title")}
+                    </span>
+                    <Select
+                      data-category={category}
+                      data-field="placement"
+                      aria-labelledby={`${id}-${category} ${id}-placement`}
+                      options={placements}
+                      current={props.value[category].placement}
+                      label={(value) => language.t(`settings.timeline.placement.${value}`)}
+                      onSelect={(placement) =>
+                        placement &&
+                        props.onChange({ ...props.value, [category]: { ...props.value[category], placement } })
+                      }
+                    />
+                  </div>
+                  <div data-slot="timeline-detail-expansion">
+                    {category === "shell" || category === "edit" || category === "thinking" ? (
+                      <Show when={props.value[category].placement !== "hidden"}>
+                        <span data-slot="timeline-detail-field-label" aria-hidden="true">
+                          {language.t("settings.timeline.expansion.title")}
+                        </span>
+                        <Select
+                          data-category={category}
+                          data-field="details"
+                          aria-labelledby={`${id}-${category} ${id}-expansion`}
+                          options={expansions}
+                          current={props.value[category].details}
+                          label={(value) => language.t(`settings.timeline.expansion.${value}`)}
+                          onSelect={(details) =>
+                            details &&
+                            props.onChange({ ...props.value, [category]: { ...props.value[category], details } })
+                          }
+                        />
+                      </Show>
+                    ) : null}
+                  </div>
+                </div>
+              )}
+            </For>
+          </div>
+        </Collapsible.Content>
+      </Collapsible>
+    </div>
+  )
+}
diff --git a/packages/session-ui/package.json b/packages/session-ui/package.json
index b7b1d0d8b7b..7b7c8692112 100644
--- a/packages/session-ui/package.json
+++ b/packages/session-ui/package.json
@@ -9,6 +9,7 @@
     "./document": "./src/document.ts",
     "./message": "./src/message/current-message.tsx",
     "./timeline/projection": "./src/timeline/projection.ts",
+    "./timeline/detail": "./src/timeline/detail.ts",
     "./timeline/row": "./src/timeline/session-timeline-row.tsx",
     "./timeline": "./src/timeline/session-timeline.tsx",
     "./basic-tool": "./src/components/basic-tool.tsx",
diff --git a/packages/session-ui/src/message/current-message.tsx b/packages/session-ui/src/message/current-message.tsx
index a2df5e6af96..cfe53b02ad9 100644
--- a/packages/session-ui/src/message/current-message.tsx
+++ b/packages/session-ui/src/message/current-message.tsx
@@ -3,15 +3,10 @@ import type {
   SessionMessageAssistantTool,
   SessionMessageUser,
 } from "@opencode-ai/client/promise"
-import { Match, Switch } from "solid-js"
+import { Match, Switch, type ComponentProps } from "solid-js"
 import type { SessionUserActions, SessionUserComment } from "../actions"
 import { AssistantReasoningContent, AssistantTextContent, CurrentUserMessageDisplay } from "./message-content"
-import {
-  CurrentContextToolGroup,
-  CurrentFileToolGroup,
-  ToolDisplay,
-  type ContextGroupPart,
-} from "../tools/tool-renderer"
+import { CurrentContextToolGroup, CurrentFileToolGroup, ToolDisplay } from "../tools/tool-renderer"
 import { currentToolError, currentToolInput, currentToolMetadata, currentToolOutput } from "./current-tool-state"
 
 export type { SessionUserActions, SessionUserComment } from "../actions"
@@ -101,28 +96,8 @@ export function SessionAssistantContent(props: {
   )
 }
 
-export function SessionContextToolGroup(props: {
-  parts: ContextGroupPart[]
-  reasoningDefaultOpen?: boolean
-  reasoningOpen?: (id: string) => boolean | undefined
-  onReasoningOpenChange?: (id: string, open: boolean) => void
-  open: boolean
-  busy: boolean
-  onOpenChange: (open: boolean) => void
-  onSizeChange?: () => void
-}) {
-  return (
-    <CurrentContextToolGroup
-      parts={props.parts}
-      reasoningDefaultOpen={props.reasoningDefaultOpen}
-      reasoningOpen={props.reasoningOpen}
-      onReasoningOpenChange={props.onReasoningOpenChange}
-      open={props.open}
-      busy={props.busy}
-      onOpenChange={props.onOpenChange}
-      onSizeChange={props.onSizeChange}
-    />
-  )
+export function SessionContextToolGroup(props: ComponentProps<typeof CurrentContextToolGroup>) {
+  return <CurrentContextToolGroup {...props} />
 }
 
 export function SessionFileToolGroup(props: {
diff --git a/packages/session-ui/src/message/current-tool-state.ts b/packages/session-ui/src/message/current-tool-state.ts
index d2da83d8c2a..b4ba572fad9 100644
--- a/packages/session-ui/src/message/current-tool-state.ts
+++ b/packages/session-ui/src/message/current-tool-state.ts
@@ -29,6 +29,42 @@ export function currentToolError(tool: SessionMessageAssistantTool) {
   return tool.state.error.message
 }
 
+export function currentToolFailed(tool: SessionMessageAssistantTool) {
+  return (
+    tool.state.status === "error" ||
+    (tool.name === "execute" && executeToolFailed(currentToolMetadata(tool))) ||
+    (tool.name === "shell" && tool.state.status === "completed" && shellResultFailed(currentToolMetadata(tool)))
+  )
+}
+
+export function shellResultFailed(metadata: Record<string, unknown>) {
+  // Shell completion reports the process outcome in metadata, not the tool status.
+  return metadata.timeout === true || (typeof metadata.exit === "number" && metadata.exit !== 0)
+}
+
+export function executeToolFailed(metadata: Record<string, unknown>) {
+  // Code Mode can report failed nested calls in a completed tool result.
+  const calls = metadata.toolCalls
+  return (
+    metadata.error === true ||
+    (Array.isArray(calls) &&
+      calls.some(
+        (call) =>
+          call !== null &&
+          typeof call === "object" &&
+          !Array.isArray(call) &&
+          "status" in call &&
+          call.status === "error",
+      ))
+  )
+}
+
+export function currentToolHasLoadedFiles(tool: SessionMessageAssistantTool) {
+  if (tool.name !== "read" || tool.state.status !== "completed") return false
+  const loaded = tool.state.metadata?.loaded
+  return Array.isArray(loaded) && loaded.some((path) => typeof path === "string")
+}
+
 export function currentContentDefaultOpen(
   content: SessionMessageAssistant["content"][number],
   shellExpanded: boolean,
diff --git a/packages/session-ui/src/timeline/detail.ts b/packages/session-ui/src/timeline/detail.ts
new file mode 100644
index 00000000000..7af3a788449
--- /dev/null
+++ b/packages/session-ui/src/timeline/detail.ts
@@ -0,0 +1,109 @@
+import type { SessionMessageAssistant, SessionMessageInfo } from "@opencode-ai/client/promise"
+import { shellResultFailed } from "../message/current-tool-state"
+
+export const timelineCategories = ["shell", "edit", "thinking", "subagents", "notices", "tools"] as const
+export type TimelineCategory = (typeof timelineCategories)[number]
+export type TimelinePlacement = "separate" | "grouped" | "hidden"
+export type TimelineExpansion = "collapsed" | "expanded"
+export type TimelineDetail = {
+  shell: { placement: TimelinePlacement; details: TimelineExpansion }
+  edit: { placement: TimelinePlacement; details: TimelineExpansion }
+  thinking: { placement: TimelinePlacement; details: TimelineExpansion }
+  subagents: { placement: TimelinePlacement }
+  notices: { placement: TimelinePlacement }
+  tools: { placement: TimelinePlacement }
+}
+
+export const timelinePresets = [
+  {
+    id: "everything",
+    value: {
+      shell: { placement: "separate", details: "expanded" },
+      edit: { placement: "separate", details: "expanded" },
+      thinking: { placement: "separate", details: "expanded" },
+      subagents: { placement: "separate" },
+      notices: { placement: "separate" },
+      tools: { placement: "separate" },
+    },
+  },
+  {
+    id: "detailed",
+    value: {
+      shell: { placement: "separate", details: "expanded" },
+      edit: { placement: "separate", details: "expanded" },
+      thinking: { placement: "grouped", details: "collapsed" },
+      subagents: { placement: "separate" },
+      notices: { placement: "grouped" },
+      tools: { placement: "grouped" },
+    },
+  },
+  {
+    id: "compact",
+    value: {
+      shell: { placement: "grouped", details: "collapsed" },
+      edit: { placement: "grouped", details: "collapsed" },
+      thinking: { placement: "grouped", details: "collapsed" },
+      subagents: { placement: "grouped" },
+      notices: { placement: "grouped" },
+      tools: { placement: "grouped" },
+    },
+  },
+  {
+    id: "quiet",
+    value: {
+      shell: { placement: "hidden", details: "collapsed" },
+      edit: { placement: "grouped", details: "collapsed" },
+      thinking: { placement: "hidden", details: "collapsed" },
+      subagents: { placement: "grouped" },
+      notices: { placement: "hidden" },
+      tools: { placement: "hidden" },
+    },
+  },
+  {
+    id: "text-only",
+    value: {
+      shell: { placement: "hidden", details: "collapsed" },
+      edit: { placement: "hidden", details: "collapsed" },
+      thinking: { placement: "hidden", details: "collapsed" },
+      subagents: { placement: "hidden" },
+      notices: { placement: "hidden" },
+      tools: { placement: "hidden" },
+    },
+  },
+] as const satisfies readonly { id: string; value: TimelineDetail }[]
+
+export function timelinePreset(value: TimelineDetail) {
+  return timelinePresets.find((preset) =>
+    timelineCategories.every((category) => {
+      const current = value[category]
+      const expected = preset.value[category]
+      return (
+        current.placement === expected.placement &&
+        (current.placement === "hidden" ||
+          !("details" in current) ||
+          ("details" in expected && current.details === expected.details))
+      )
+    }),
+  )
+}
+
+export function timelineCategory(
+  content: SessionMessageAssistant["content"][number],
+): keyof TimelineDetail | undefined {
+  if (content.type === "text") return
+  if (content.type === "reasoning") return "thinking"
+  if (["shell", "execute", "bash"].includes(content.name)) return "shell"
+  if (["edit", "write", "patch", "apply_patch"].includes(content.name)) return "edit"
+  if (["subagent", "task"].includes(content.name)) return "subagents"
+  return "tools"
+}
+
+export function timelineNoticeRequired(message: SessionMessageInfo) {
+  if (message.type === "compaction") return message.status !== "completed"
+  if (message.type !== "synthetic") return false
+  const metadata = message.metadata
+  return (
+    metadata?.state === "error" ||
+    (metadata?.source === "shell" && metadata.state === "completed" && shellResultFailed(metadata))
+  )
+}
diff --git a/packages/session-ui/src/timeline/projection.ts b/packages/session-ui/src/timeline/projection.ts
index 73ff609a96a..d128dae74aa 100644
--- a/packages/session-ui/src/timeline/projection.ts
+++ b/packages/session-ui/src/timeline/projection.ts
@@ -8,8 +8,9 @@ import type {
 } from "@opencode-ai/client/promise"
 import { Option, Schema } from "effect"
 import { createMemo, mapArray, type Accessor } from "solid-js"
-import { currentContentDefaultOpen } from "../message/current-tool-state"
+import { currentContentDefaultOpen, currentToolFailed, currentToolHasLoadedFiles } from "../message/current-tool-state"
 import { TimelineRow, type PartGroup, type PartRef, type TimelineRowMap } from "./timeline-row"
+import { timelineCategory, timelineNoticeRequired, type TimelineDetail } from "./detail"
 
 export { TimelineRow, type PartGroup, type PartRef, type TimelineRowMap }
 
@@ -29,6 +30,7 @@ export type TimelineProjectionInput = {
   reasoningMode: ReasoningMode
   shellToolDefaultOpen?: boolean
   editToolDefaultOpen?: boolean
+  timelineDetail?: TimelineDetail
   pendingUserMessageIDs?: ReadonlySet<string>
   previousRows?: TimelineRow.TimelineRow[]
 }
@@ -42,6 +44,8 @@ export function createTimelineProjection(input: TimelineProjectionInput) {
     input.pendingUserMessageIDs,
     input.shellToolDefaultOpen ?? false,
     input.editToolDefaultOpen ?? false,
+    undefined,
+    input.timelineDetail,
   )
   const rows = reuseTimelineRows(input.previousRows, projection.rows)
   const rowByKey = new Map(rows.map((row) => [TimelineRow.key(row), row] as const))
@@ -75,6 +79,7 @@ export function createReactiveTimelineProjection(input: {
   reasoningMode: Accessor<ReasoningMode>
   shellToolDefaultOpen?: Accessor<boolean>
   editToolDefaultOpen?: Accessor<boolean>
+  timelineDetail?: Accessor<TimelineDetail>
   pendingUserMessageIDs?: Accessor<ReadonlySet<string>>
 }) {
   const sessionMessageByID = createMemo(
@@ -102,10 +107,12 @@ export function createReactiveTimelineProjection(input: {
       input.pendingUserMessageIDs?.(),
       input.shellToolDefaultOpen?.() ?? false,
       input.editToolDefaultOpen?.() ?? false,
-      (content, showReasoning) =>
+      (content, showReasoning, detail) =>
         content.type === "tool"
-          ? renderable(content, showReasoning)
-          : (content.type === "text" || showReasoning) && textVisible().get(content)!(),
+          ? renderable(content, showReasoning, detail)
+          : (content.type === "text" || (detail ? detail.thinking.placement !== "hidden" : showReasoning)) &&
+            textVisible().get(content)!(),
+      input.timelineDetail?.(),
     ),
   )
   const activeMessageID = createMemo(() => projection().activeMessageID)
@@ -157,6 +164,7 @@ export namespace Timeline {
     shellToolDefaultOpen = false,
     editToolDefaultOpen = false,
     isRenderable = renderable,
+    detail?: TimelineDetail,
   ) {
     type Turn = {
       id: string
@@ -208,37 +216,68 @@ export namespace Timeline {
     })
 
     const activeMessageID = turns.findLast((turn) => !pendingUserMessageIDs?.has(turn.id))?.id ?? turns.at(-1)?.id
+    const visibleNotice = (message: Notice) =>
+      !detail || detail.notices.placement !== "hidden" || timelineNoticeRequired(message)
+    const visibleTurns = detail
+      ? turns.filter((turn) => {
+          if (turn.user) return true
+          if (turn.shell && (detail.shell.placement !== "hidden" || shellFailed(turn.shell))) return true
+          return turn.entries.some((entry) =>
+            entry.type === "notice"
+              ? visibleNotice(entry.message)
+              : !!entry.message.error ||
+                !!entry.message.retry ||
+                entry.message.content.some((content) => isRenderable(content, showReasoning, detail)),
+          )
+        })
+      : turns
+    const rows: TimelineRow.TimelineRow[] = [
+      ...leading
+        .filter(visibleNotice)
+        .map((message) => new TimelineRow.Notice({ userMessageID: turns[0]?.id ?? message.id, messageID: message.id })),
+      ...visibleTurns.flatMap((turn, index) => {
+        if (turn.shell)
+          return [
+            ...(index > 0 ? [new TimelineRow.TurnGap({ userMessageID: turn.id })] : []),
+            ...(!detail || detail.shell.placement !== "hidden" || shellFailed(turn.shell)
+              ? [new TimelineRow.Shell({ userMessageID: turn.id, messageID: turn.shell.id })]
+              : []),
+            ...turn.entries.flatMap((entry) =>
+              entry.type === "notice" && visibleNotice(entry.message)
+                ? [new TimelineRow.Notice({ userMessageID: turn.id, messageID: entry.message.id })]
+                : [],
+            ),
+          ]
+        return constructMessageRows(
+          turn.user,
+          turn.id,
+          turn.entries,
+          index,
+          showReasoning,
+          status,
+          turn.id === activeMessageID,
+          shellToolDefaultOpen,
+          editToolDefaultOpen,
+          isRenderable,
+          detail,
+        )
+      }),
+    ]
     return {
       activeMessageID,
-      rows: [
-        ...leading.map(
-          (message) => new TimelineRow.Notice({ userMessageID: turns[0]?.id ?? message.id, messageID: message.id }),
-        ),
-        ...turns.flatMap((turn, index) => {
-          if (turn.shell)
-            return [
-              ...(index > 0 ? [new TimelineRow.TurnGap({ userMessageID: turn.id })] : []),
-              new TimelineRow.Shell({ userMessageID: turn.id, messageID: turn.shell.id }),
-              ...turn.entries.flatMap((entry) =>
-                entry.type === "notice"
-                  ? [new TimelineRow.Notice({ userMessageID: turn.id, messageID: entry.message.id })]
-                  : [],
-              ),
-            ]
-          return constructMessageRows(
-            turn.user,
-            turn.id,
-            turn.entries,
-            index,
-            showReasoning,
-            status,
-            turn.id === activeMessageID,
-            shellToolDefaultOpen,
-            editToolDefaultOpen,
-            isRenderable,
+      rows: detail
+        ? groupMessages(
+            rows,
+            detail,
+            new Set(
+              messages
+                .filter(
+                  (message) => timelineNoticeRequired(message) || (message.type === "shell" && shellFailed(message)),
+                )
+                .map((message) => message.id),
+            ),
           )
-        }),
-      ],
+        : rows,
     }
   }
 
@@ -253,6 +292,7 @@ export namespace Timeline {
     shellToolDefaultOpen = false,
     editToolDefaultOpen = false,
     isRenderable = renderable,
+    detail?: TimelineDetail,
   ) {
     const rows: TimelineRow.TimelineRow[] = []
     const assistantMessages = entries.flatMap((entry) => (entry.type === "assistant" ? [entry.message] : []))
@@ -261,7 +301,7 @@ export namespace Timeline {
     const compaction = entries.some((entry) => entry.type === "notice" && entry.message.type === "compaction")
     const lastContent = lastAssistant?.content.at(-1)
     const thinking =
-      showReasoning &&
+      (detail ? detail.thinking.placement === "separate" : showReasoning) &&
       isActive &&
       status.type === "busy" &&
       lastAssistant?.time.completed === undefined &&
@@ -280,7 +320,9 @@ export namespace Timeline {
     const appendAssistantSegment = (messages: SessionMessageAssistant[]) => {
       const refs = messages.flatMap((message, messageIndex) =>
         contentEntries(message)
-          .filter((entry) => isRenderable(entry.content, showReasoning) && !(thinking && entry.content === lastContent))
+          .filter(
+            (entry) => isRenderable(entry.content, showReasoning, detail) && !(thinking && entry.content === lastContent),
+          )
           .map((entry) => ({ messageID: message.id, messageIndex, partID: entry.id, content: entry.content })),
       )
       const interruptedAt = messages.findIndex((message) => isInterrupted(message.error))
@@ -288,7 +330,7 @@ export namespace Timeline {
       const after = interruptedAt < 0 ? [] : refs.filter((ref) => ref.messageIndex > interruptedAt)
       const appendGroups = (items: typeof refs) => {
         let offset = 0
-        groupContent(items, shellToolDefaultOpen, editToolDefaultOpen).forEach((group) => {
+        groupContent(items, shellToolDefaultOpen, editToolDefaultOpen, detail).forEach((group) => {
           const tool = group.type !== "part" || items[offset]?.content.type !== "text"
           offset += group.type === "part" ? 1 : group.refs.length
           rows.push(
@@ -306,7 +348,8 @@ export namespace Timeline {
 
       appendGroups(before)
       if (interruptedAt >= 0) {
-        if (!compaction) rows.push(new TimelineRow.TurnDivider({ userMessageID: turnID }))
+        if (!compaction && detail?.notices.placement !== "hidden")
+          rows.push(new TimelineRow.TurnDivider({ userMessageID: turnID }))
         appendGroups(after)
       }
 
@@ -325,6 +368,7 @@ export namespace Timeline {
           assistantSegment.push(entry.message)
           return
         case "notice":
+          if (detail?.notices.placement === "hidden" && !timelineNoticeRequired(entry.message)) return
           appendAssistantSegment(assistantSegment)
           assistantSegment = []
           rows.push(new TimelineRow.Notice({ userMessageID: turnID, messageID: entry.message.id }))
@@ -366,6 +410,48 @@ function isInterrupted(error: SessionMessageAssistant["error"]) {
   return error?.type.toLowerCase().includes("abort") || error?.type.toLowerCase().includes("interrupt")
 }
 
+function shellFailed(message: SessionMessageShell) {
+  return (
+    message.status === "timeout" || (message.status === "exited" && message.exit !== undefined && message.exit !== 0)
+  )
+}
+
+function groupMessages(rows: TimelineRow.TimelineRow[], detail: TimelineDetail, required: ReadonlySet<string>) {
+  return rows.reduce<TimelineRow.TimelineRow[]>((result, row) => {
+    const previous = result.at(-1)
+    const current =
+      ((row._tag === "Notice" && detail.notices.placement === "grouped") ||
+        (row._tag === "Shell" && detail.shell.placement === "grouped")) &&
+      !required.has(row.messageID)
+        ? new TimelineRow.AssistantPart({
+            userMessageID: row.userMessageID,
+            previousAssistantPart: previous?._tag === "AssistantPart",
+            spacing: previous?._tag === "AssistantPart" ? "tool" : undefined,
+            group: {
+              type: "context",
+              key: `message:${row.messageID}`,
+              refs: [{ messageID: row.messageID, partID: row.messageID }],
+            },
+          })
+        : row
+    if (
+      previous?._tag === "AssistantPart" &&
+      previous.group.type === "context" &&
+      current._tag === "AssistantPart" &&
+      current.group.type === "context" &&
+      previous.userMessageID === current.userMessageID
+    ) {
+      result[result.length - 1] = new TimelineRow.AssistantPart({
+        ...previous,
+        group: { ...previous.group, refs: [...previous.group.refs, ...current.group.refs] },
+      })
+      return result
+    }
+    result.push(current)
+    return result
+  }, [])
+}
+
 export function reuseTimelineRows(previous: TimelineRow.TimelineRow[] | undefined, rows: TimelineRow.TimelineRow[]) {
   if (!previous?.length) return rows
   const byKey = new Map(previous.map((row) => [TimelineRow.key(row), row] as const))
@@ -494,11 +580,14 @@ function groupPartKey(ref: PartRef) {
   return `${ref.messageID}:${ref.partID}`
 }
 
-function renderable(content: Content, showReasoning: boolean) {
+function renderable(content: Content, showReasoning: boolean, detail?: TimelineDetail) {
   if (content.type === "text") return !!content.text.trim()
-  if (content.type === "reasoning") return showReasoning && !!content.text.trim()
+  if (content.type === "reasoning")
+    return (detail ? detail.thinking.placement !== "hidden" : showReasoning) && !!content.text.trim()
+  if (detail && currentToolFailed(content)) return true
   if (content.name === "todowrite") return false
   if (content.name === "question") return content.state.status !== "streaming" && content.state.status !== "running"
+  if (detail && detail[timelineCategory(content)!].placement === "hidden") return false
   return true
 }
 
@@ -506,6 +595,7 @@ function groupContent(
   items: { messageID: string; partID: string; content: Content }[],
   shellToolDefaultOpen: boolean,
   editToolDefaultOpen: boolean,
+  detail?: TimelineDetail,
 ): PartGroup[] {
   const groups: PartGroup[] = []
   let adjacent: { type: "context" | "patch" | "edit"; refs: PartRef[]; tools: boolean } | undefined
@@ -513,7 +603,7 @@ function groupContent(
     const current = adjacent
     const first = current?.refs[0]
     if (!first) return
-    if (!current.tools) {
+    if (!current.tools && !detail) {
       groups.push(
         ...current.refs.map((ref) => ({ type: "part" as const, key: `part:${ref.messageID}:${ref.partID}`, ref })),
       )
@@ -539,9 +629,12 @@ function groupContent(
             shellToolDefaultOpen,
             editToolDefaultOpen,
             adjacent?.type === "context" && adjacent.tools,
+            detail,
           )
         : item.content.type === "reasoning"
-          ? "context"
+          ? detail && detail.thinking.placement !== "grouped"
+            ? undefined
+            : "context"
           : undefined
     if (type) {
       if (adjacent?.type !== type) flush()
@@ -566,8 +659,17 @@ function toolGroupType(
   shellExpanded: boolean,
   editExpanded: boolean,
   hasContextGroup: boolean,
+  detail?: TimelineDetail,
 ) {
-  if (content.name === "question" || hasLoadedFiles(content)) return undefined
+  if (detail) {
+    if (currentToolFailed(content) || content.name === "question") return undefined
+    const category = timelineCategory(content)!
+    if (detail[category].placement === "grouped") return "context"
+    if (content.name === "patch") return "patch"
+    if (content.name === "edit") return "edit"
+    return undefined
+  }
+  if (content.name === "question" || currentToolHasLoadedFiles(content)) return undefined
   if (content.state.status === "error") {
     if ((content.name === "shell" || content.name === "execute") && shellExpanded) return undefined
     if ((content.name === "edit" || content.name === "write" || content.name === "patch") && editExpanded)
@@ -587,12 +689,6 @@ function toolGroupType(
   return undefined
 }
 
-function hasLoadedFiles(content: Extract<Content, { type: "tool" }>) {
-  if (content.name !== "read" || content.state.status !== "completed") return false
-  const loaded = content.state.metadata?.loaded
-  return Array.isArray(loaded) && loaded.some((path) => typeof path === "string")
-}
-
 export function reasoningHeading(text: string): string | undefined {
   const markdown = text.replace(/\r\n?/g, "\n")
   const html = markdown.match(/<h[1-6][^>]*>([\s\S]*?)<\/h[1-6]>/i)
@@ -671,5 +767,5 @@ function record(value: unknown): value is Record<string, unknown> {
 function isNotice(message: SessionMessageInfo): message is Notice {
   if (message.type === "user" || message.type === "assistant" || message.type === "shell") return false
   if (message.type !== "synthetic") return true
-  return !!message.description?.trim()
+  return !!message.description?.trim() || timelineNoticeRequired(message)
 }
diff --git a/packages/session-ui/src/timeline/session-timeline-row.tsx b/packages/session-ui/src/timeline/session-timeline-row.tsx
index 7655b4965c4..e5420d8f7f6 100644
--- a/packages/session-ui/src/timeline/session-timeline-row.tsx
+++ b/packages/session-ui/src/timeline/session-timeline-row.tsx
@@ -22,6 +22,8 @@ import {
 import { AssistantReasoningContent, SessionCompactionMessage } from "../message/message-content"
 import type { ContextGroupPart } from "../tools/tool-renderer"
 import { SessionRetry } from "../components/session-retry"
+import { timelineCategory, type TimelineDetail } from "./detail"
+import { currentToolFailed } from "../message/current-tool-state"
 import {
   createReactiveTimelineProjection,
   Timeline,
@@ -49,9 +51,11 @@ export function createSessionTimelineRowRenderer(input: {
   reasoningMode: Accessor<ReasoningMode>
   shellToolDefaultOpen: Accessor<boolean>
   editToolDefaultOpen: Accessor<boolean>
+  timelineDetail?: Accessor<TimelineDetail>
   disclosure: {
     value: (key: string) => boolean | undefined
     set: (key: string, open: boolean) => void
+    patchGroupKeys?: Map<string, string>
   }
   centered?: Accessor<boolean>
   padding?: Accessor<string>
@@ -59,6 +63,21 @@ export function createSessionTimelineRowRenderer(input: {
 }) {
   const i18n = useI18n()
   const data = useData()
+  // Cached timelines retain subgroup identities alongside their disclosure choices.
+  const patchGroupKeys = input.disclosure.patchGroupKeys ?? new Map<string, string>()
+  const patchPartKeys = new WeakMap<SessionMessageAssistant["content"][number], string>()
+  const patchOwners = createMemo(() => {
+    const owners = new Map<string, string>()
+    input.projection.rows().forEach((row) => {
+      if (row._tag !== "AssistantPart" || row.group.type !== "context") return
+      row.group.refs.forEach((ref) => {
+        const part = `${ref.messageID}:${ref.partID}`
+        const key = patchGroupKeys.get(part)
+        if (key && !owners.has(key)) owners.set(key, part)
+      })
+    })
+    return owners
+  })
   const workingTurn = (messageID: string) =>
     input.status().type !== "idle" && input.projection.activeMessageID() === messageID
   const duration = (messageID: string) => {
@@ -104,10 +123,35 @@ export function createSessionTimelineRowRenderer(input: {
         const group = row().group
         if (group.type !== "context") return []
         const contents = indexGroupContents(group.refs)
+        const lastAssistant = input.projection.assistantMessagesByParent().get(row().userMessageID)?.at(-1)
         return group.refs.flatMap<ContextGroupPart>((ref) => {
           const content = contents.get(ref.messageID)?.get(ref.partID)
-          if (content?.type === "tool") return [content]
-          if (content?.type === "reasoning") return [{ ...content, id: ref.partID }]
+          if (content?.type === "tool") {
+            patchPartKeys.set(content, `${ref.messageID}:${ref.partID}`)
+            return [content]
+          }
+          if (content?.type === "reasoning")
+            return [
+              {
+                ...content,
+                id: ref.partID,
+                streaming:
+                  workingTurn(row().userMessageID) &&
+                  input.status().type === "busy" &&
+                  lastAssistant?.id === ref.messageID &&
+                  lastAssistant.time.completed === undefined &&
+                  !lastAssistant.error &&
+                  !lastAssistant.retry &&
+                  lastAssistant.content.at(-1) === content &&
+                  content.time?.completed === undefined,
+              },
+            ]
+          const message = input.projection.messageByID().get(ref.messageID)
+          if (ref.messageID !== ref.partID || !message) return []
+          if (message.type === "shell")
+            return [{ type: "shell", id: ref.partID, render: () => <Shell messageID={ref.messageID} grouped /> }]
+          if (message.type !== "assistant" && message.type !== "user")
+            return [{ type: "notice", id: ref.partID, render: () => <Notice messageID={ref.messageID} grouped /> }]
           return []
         })
       })
@@ -115,9 +159,30 @@ export function createSessionTimelineRowRenderer(input: {
       return (
         <SessionContextToolGroup
           parts={parts()}
-          reasoningDefaultOpen={input.reasoningMode() === "full"}
+          patchGroupKey={(tools) => {
+            const parts = tools.map((tool) => patchPartKeys.get(tool)!)
+            // After a split, only the subgroup with the earliest surviving member keeps the old anchor.
+            const key =
+              parts
+                .map((part) => patchGroupKeys.get(part))
+                .find((key) => key !== undefined && parts.includes(patchOwners().get(key)!)) ?? parts[0]!
+            parts.forEach((part) => patchGroupKeys.set(part, key))
+            return key
+          }}
+          reasoningDefaultOpen={
+            input.timelineDetail
+              ? input.timelineDetail().thinking.details === "expanded"
+              : input.reasoningMode() === "full"
+          }
           reasoningOpen={(id) => input.disclosure.value(id)}
           onReasoningOpenChange={(id, open) => input.disclosure.set(id, open)}
+          toolDefaultOpen={(tool) => (input.timelineDetail ? contentDefaultOpen(tool) : false)}
+          toolOpen={(id) => input.disclosure.value(`${row().group.key}:tool:${id}`)}
+          onToolOpenChange={(id, open) => input.disclosure.set(`${row().group.key}:tool:${id}`, open)}
+          fileOpen={(path) =>
+            input.disclosure.value(`patch:${path}`) ?? input.timelineDetail?.().edit.details === "expanded"
+          }
+          onFileOpenChange={(path, open) => input.disclosure.set(`patch:${path}`, open)}
           open={input.disclosure.value(key()) === true}
           busy={
             workingTurn(row().userMessageID) &&
@@ -155,6 +220,7 @@ export function createSessionTimelineRowRenderer(input: {
           fileOpen={(path) => {
             const open = input.disclosure.value(`${row().group.key}:file:${path}`)
             if (open !== undefined) return open
+            if (input.timelineDetail) return input.timelineDetail().edit.details === "expanded"
             if (tools()[0]?.name !== "edit" || path !== firstPath()) return false
             return input.disclosure.value(row().group.key) ?? input.editToolDefaultOpen()
           }}
@@ -179,9 +245,7 @@ export function createSessionTimelineRowRenderer(input: {
     })
     const defaultOpen = createMemo(() => {
       const item = content()
-      if (!item) return undefined
-      if (item.type === "reasoning") return input.reasoningMode() === "full"
-      return currentContentDefaultOpen(item, input.shellToolDefaultOpen(), input.editToolDefaultOpen())
+      return item ? contentDefaultOpen(item) : undefined
     })
     const disclosureKey = () => (content()?.type === "reasoning" ? ref()!.partID : row().group.key)
     return (
@@ -207,6 +271,17 @@ export function createSessionTimelineRowRenderer(input: {
     )
   }
 
+  function contentDefaultOpen(item: SessionMessageAssistant["content"][number]) {
+    if (input.timelineDetail) {
+      if (item.type === "tool" && currentToolFailed(item)) return true
+      const category = timelineCategory(item)
+      if (category === "shell" || category === "edit" || category === "thinking")
+        return input.timelineDetail()[category].details === "expanded"
+    }
+    if (item.type === "reasoning") return input.reasoningMode() === "full"
+    return currentContentDefaultOpen(item, input.shellToolDefaultOpen(), input.editToolDefaultOpen())
+  }
+
   const notice = (message: SessionMessageInfo) => {
     if (message.type === "agent-switched")
       return {
@@ -271,6 +346,168 @@ export function createSessionTimelineRowRenderer(input: {
     </div>
   )
 
+  function Notice(props: { messageID: string; grouped?: boolean }) {
+    const inset = () => (props.grouped ? "" : padding())
+    const message = createMemo(() => input.projection.messageByID().get(props.messageID))
+    const compaction = createMemo(() => {
+      const value = message()
+      return value?.type === "compaction" ? value : undefined
+    })
+    const compactionError = createMemo(() => {
+      const value = compaction()
+      if (value?.status !== "failed") return ""
+      return unwrapErrorMessage(value.error.message)
+    })
+    const moved = createMemo(() => {
+      const value = message()
+      return value?.type === "location-switched" ? value : undefined
+    })
+    const model = createMemo(() => {
+      const value = message()
+      if (value?.type !== "model-switched") return undefined
+      const match = data.store.provider?.all?.get(value.model.providerID)
+      return {
+        providerID: value.model.providerID,
+        variant: value.model.variant,
+        label: i18n.t("ui.sessionTimeline.notice.modelSwitched", {
+          model: match?.models?.[value.model.id]?.name ?? value.model.id,
+        }),
+      }
+    })
+    const content = createMemo(() => {
+      const value = message()
+      return value ? notice(value) : undefined
+    })
+    return (
+      <>
+        <Show when={compaction()}>
+          {(message) => (
+            <div data-slot="session-turn-message-container" class={`w-full ${inset()}`}>
+              <div data-slot="session-turn-compaction">
+                <SessionCompactionMessage message={message()} error={compactionError()} />
+              </div>
+            </div>
+          )}
+        </Show>
+        <Show
+          when={moved()}
+          fallback={
+            <Show
+              when={model()}
+              fallback={
+                <Show when={content()}>
+                  {(content) => (
+                    <Show
+                      when={content().items?.length}
+                      fallback={
+                        <div
+                          data-slot="session-timeline-notice"
+                          class={`w-full truncate ${props.grouped ? "py-1" : "pt-3 pb-1"} text-13-regular leading-text-compact text-text-weak ${inset()}`}
+                        >
+                          <bdi dir="auto" class="text-13-medium">
+                            {content().label}
+                          </bdi>
+                          <Show when={content().data}>
+                            {(data) => (
+                              <span>
+                                {" "}
+                                · <bdi dir="auto">{data()}</bdi>
+                              </span>
+                            )}
+                          </Show>
+                        </div>
+                      }
+                    >
+                      <div data-slot="session-timeline-notice" class={`w-full py-1 ${inset()}`}>
+                        <div class="flex min-h-5 min-w-0 items-center gap-2 overflow-hidden">
+                          <bdi
+                            dir="auto"
+                            class="shrink-0 text-[13px] font-[530] leading-text-compact tracking-[-0.04px] text-v2-text-text-faint"
+                          >
+                            {content().label}
+                          </bdi>
+                          <For each={content().items}>
+                            {(item) => (
+                              <bdi
+                                dir="auto"
+                                class="min-w-0 truncate text-[13px] font-[440] leading-text-compact tracking-[-0.04px] text-v2-text-text-faint"
+                              >
+                                {item}
+                              </bdi>
+                            )}
+                          </For>
+                        </div>
+                      </div>
+                    </Show>
+                  )}
+                </Show>
+              }
+            >
+              {(model) => (
+                <div data-slot="session-timeline-notice" data-type="model-switched" class={`w-full py-2 ${inset()}`}>
+                  <TimelineSeparator label={model().label} providerID={model().providerID} variant={model().variant} />
+                </div>
+              )}
+            </Show>
+          }
+        >
+          {(message) => (
+            <div
+              data-slot="session-timeline-notice"
+              data-type="location-switched"
+              class={`flex h-7 w-full min-w-0 items-center gap-2 py-1 text-[13px] leading-text-compact tracking-[-0.04px] text-v2-text-text-faint ${inset()}`}
+            >
+              <Tooltip
+                appearance="compact"
+                placement="top"
+                value={i18n.t("ui.sessionTimeline.notice.movedTooltip")}
+                class="shrink-0"
+                triggerTabIndex={0}
+              >
+                <bdi data-slot="session-timeline-notice-label" dir="auto" class="font-[530]">
+                  {i18n.t("ui.sessionTimeline.notice.movedTo")}
+                </bdi>
+              </Tooltip>{" "}
+              <bdi data-slot="session-timeline-notice-value" dir="ltr" class="min-w-0 truncate font-[440]">
+                {message().location.directory}
+              </bdi>
+            </div>
+          )}
+        </Show>
+      </>
+    )
+  }
+
+  function Shell(props: { messageID: string; grouped?: boolean }) {
+    const message = createMemo(() => {
+      const value = input.projection.messageByID().get(props.messageID)
+      return value?.type === "shell" ? value : undefined
+    })
+    const defaultOpen = createMemo(() => {
+      if (!input.timelineDetail) return input.shellToolDefaultOpen()
+      const value = message()
+      return (
+        input.timelineDetail().shell.details === "expanded" ||
+        value?.status === "timeout" ||
+        (value?.status === "exited" && value.exit !== undefined && value.exit !== 0)
+      )
+    })
+    return (
+      <Show when={message()}>
+        {(message) => (
+          <div data-slot="session-turn-message-container" class={`w-full ${props.grouped ? "" : padding()}`}>
+            <SessionShellMessage
+              message={message()}
+              defaultOpen={defaultOpen()}
+              open={input.disclosure.value(message().id) ?? (input.timelineDetail ? defaultOpen() : undefined)}
+              onOpenChange={(open) => input.disclosure.set(message().id, open)}
+            />
+          </div>
+        )}
+      </Show>
+    )
+  }
+
   const render = (row: Accessor<TimelineRow.TimelineRow>, onSizeChange?: () => void) => {
     if (row()._tag === "TurnGap") return <div data-timeline-row="TurnGap" aria-hidden="true" class="h-6" />
     if (row()._tag === "UserMessage") {
@@ -315,24 +552,9 @@ export function createSessionTimelineRowRenderer(input: {
         if (value._tag !== "Shell") throw new Error("Expected a shell timeline row")
         return value
       }
-      const message = createMemo(() => {
-        const value = input.projection.messageByID().get(current().messageID)
-        return value?.type === "shell" ? value : undefined
-      })
       return (
         <Frame row={current()}>
-          <Show when={message()}>
-            {(message) => (
-              <div data-slot="session-turn-message-container" class={`w-full ${padding()}`}>
-                <SessionShellMessage
-                  message={message()}
-                  defaultOpen={input.shellToolDefaultOpen()}
-                  open={input.disclosure.value(message().id)}
-                  onOpenChange={(open) => input.disclosure.set(message().id, open)}
-                />
-              </div>
-            )}
-          </Show>
+          <Shell messageID={current().messageID} />
         </Frame>
       )
     }
@@ -342,140 +564,9 @@ export function createSessionTimelineRowRenderer(input: {
         if (value._tag !== "Notice") throw new Error("Expected a notice timeline row")
         return value
       }
-      const message = createMemo(() => input.projection.messageByID().get(current().messageID))
-      const compaction = createMemo(() => {
-        const value = message()
-        return value?.type === "compaction" ? value : undefined
-      })
-      const compactionError = createMemo(() => {
-        const value = compaction()
-        if (value?.status !== "failed") return ""
-        return unwrapErrorMessage(value.error.message)
-      })
-      const moved = createMemo(() => {
-        const value = message()
-        return value?.type === "location-switched" ? value : undefined
-      })
-      const model = createMemo(() => {
-        const value = message()
-        if (value?.type !== "model-switched") return undefined
-        const match = data.store.provider?.all?.get(value.model.providerID)
-        return {
-          providerID: value.model.providerID,
-          variant: value.model.variant,
-          label: i18n.t("ui.sessionTimeline.notice.modelSwitched", {
-            model: match?.models?.[value.model.id]?.name ?? value.model.id,
-          }),
-        }
-      })
-      const content = createMemo(() => {
-        const value = message()
-        return value ? notice(value) : undefined
-      })
       return (
         <Frame row={current()}>
-          <Show when={compaction()}>
-            {(message) => (
-              <div data-slot="session-turn-message-container" class={`w-full ${padding()}`}>
-                <div data-slot="session-turn-compaction">
-                  <SessionCompactionMessage message={message()} error={compactionError()} />
-                </div>
-              </div>
-            )}
-          </Show>
-          <Show
-            when={moved()}
-            fallback={
-              <Show
-                when={model()}
-                fallback={
-                  <Show when={content()}>
-                    {(content) => (
-                      <Show
-                        when={content().items?.length}
-                        fallback={
-                          <div
-                            data-slot="session-timeline-notice"
-                            class={`w-full truncate pt-3 pb-1 text-13-regular text-text-weak ${padding()}`}
-                          >
-                            <bdi dir="auto" class="text-13-medium">
-                              {content().label}
-                            </bdi>
-                            <Show when={content().data}>
-                              {(data) => (
-                                <span>
-                                  {" "}
-                                  · <bdi dir="auto">{data()}</bdi>
-                                </span>
-                              )}
-                            </Show>
-                          </div>
-                        }
-                      >
-                        <div data-slot="session-timeline-notice" class={`w-full py-1 ${padding()}`}>
-                          <div class="flex min-h-5 min-w-0 items-center gap-2 overflow-hidden">
-                            <bdi
-                              dir="auto"
-                              class="shrink-0 text-[13px] font-[530] leading-text-compact tracking-[-0.04px] text-v2-text-text-faint"
-                            >
-                              {content().label}
-                            </bdi>
-                            <For each={content().items}>
-                              {(item) => (
-                                <bdi
-                                  dir="auto"
-                                  class="min-w-0 truncate text-[13px] font-[440] leading-text-compact tracking-[-0.04px] text-v2-text-text-faint"
-                                >
-                                  {item}
-                                </bdi>
-                              )}
-                            </For>
-                          </div>
-                        </div>
-                      </Show>
-                    )}
-                  </Show>
-                }
-              >
-                {(model) => (
-                  <div
-                    data-slot="session-timeline-notice"
-                    data-type="model-switched"
-                    class={`w-full py-2 ${padding()}`}
-                  >
-                    <TimelineSeparator
-                      label={model().label}
-                      providerID={model().providerID}
-                      variant={model().variant}
-                    />
-                  </div>
-                )}
-              </Show>
-            }
-          >
-            {(message) => (
-              <div
-                data-slot="session-timeline-notice"
-                data-type="location-switched"
-                class={`flex h-7 w-full min-w-0 items-center gap-2 py-1 text-[13px] leading-text-compact tracking-[-0.04px] text-v2-text-text-faint ${padding()}`}
-              >
-                <Tooltip
-                  appearance="compact"
-                  placement="top"
-                  value={i18n.t("ui.sessionTimeline.notice.movedTooltip")}
-                  class="shrink-0"
-                  triggerTabIndex={0}
-                >
-                  <bdi data-slot="session-timeline-notice-label" dir="auto" class="font-[530]">
-                    {i18n.t("ui.sessionTimeline.notice.movedTo")}
-                  </bdi>
-                </Tooltip>{" "}
-                <bdi data-slot="session-timeline-notice-value" dir="ltr" class="min-w-0 truncate font-[440]">
-                  {message().location.directory}
-                </bdi>
-              </div>
-            )}
-          </Show>
+          <Notice messageID={current().messageID} />
         </Frame>
       )
     }
@@ -536,8 +627,15 @@ export function createSessionTimelineRowRenderer(input: {
                     id={current().ref.partID}
                     content={content()}
                     streaming
-                    defaultOpen={input.reasoningMode() === "full"}
-                    open={input.disclosure.value(current().ref.partID)}
+                    defaultOpen={
+                      input.timelineDetail
+                        ? input.timelineDetail().thinking.details === "expanded"
+                        : input.reasoningMode() === "full"
+                    }
+                    open={
+                      input.disclosure.value(current().ref.partID) ??
+                      (input.timelineDetail ? input.timelineDetail().thinking.details === "expanded" : undefined)
+                    }
                     onOpenChange={(open) => input.disclosure.set(current().ref.partID, open)}
                     onContentRendered={onSizeChange}
                   />
diff --git a/packages/session-ui/src/tools/tool-renderer.tsx b/packages/session-ui/src/tools/tool-renderer.tsx
index 5f16eb72bde..ea6f4cd9e4f 100644
--- a/packages/session-ui/src/tools/tool-renderer.tsx
+++ b/packages/session-ui/src/tools/tool-renderer.tsx
@@ -44,9 +44,11 @@ import type {
 } from "@opencode-ai/client/promise"
 import {
   currentToolError,
+  currentToolHasLoadedFiles,
   currentToolInput,
   currentToolMetadata,
   currentToolOutput,
+  executeToolFailed,
 } from "../message/current-tool-state"
 import { AssistantReasoningContent, writeClipboard } from "../message/message-content"
 
@@ -480,7 +482,10 @@ function ExaOutput(props: { output?: string }) {
   )
 }
 
-export type ContextGroupPart = SessionMessageAssistantTool | (SessionMessageAssistantReasoning & { id: string })
+export type ContextGroupPart =
+  | SessionMessageAssistantTool
+  | (SessionMessageAssistantReasoning & { id: string; streaming?: boolean })
+  | { type: "notice" | "shell"; id: string; render: () => JSX.Element }
 
 export function CurrentContextToolGroup(props: {
   parts: ContextGroupPart[]
@@ -491,6 +496,12 @@ export function CurrentContextToolGroup(props: {
   reasoningDefaultOpen?: boolean
   reasoningOpen?: (id: string) => boolean | undefined
   onReasoningOpenChange?: (id: string, open: boolean) => void
+  toolDefaultOpen?: (tool: SessionMessageAssistantTool) => boolean | undefined
+  toolOpen?: (id: string) => boolean | undefined
+  onToolOpenChange?: (id: string, open: boolean) => void
+  fileOpen?: (path: string) => boolean | undefined
+  onFileOpenChange?: (path: string, open: boolean) => void
+  patchGroupKey?: (tools: SessionMessageAssistantTool[]) => string
 }) {
   const i18n = useI18n()
   const tools = createMemo(() => props.parts.filter((part) => part.type === "tool"))
@@ -499,14 +510,16 @@ export function CurrentContextToolGroup(props: {
   )
   const names = createMemo(() =>
     [
-      ...tools().reduce((counts, tool) => {
-        const input = currentToolInput(tool)
+      ...props.parts.reduce((counts, part) => {
+        if (part.type !== "tool" && part.type !== "shell") return counts
         const name =
-          tool.name === "skill"
-            ? i18n.t("ui.tool.skill")
-            : tool.name === "subagent"
-              ? i18n.t("ui.tool.agent.default")
-              : getToolInfo(tool.name, input, currentToolMetadata(tool)).title
+          part.type !== "tool"
+            ? i18n.t("ui.tool.shell")
+            : part.name === "skill"
+              ? i18n.t("ui.tool.skill")
+              : part.name === "subagent"
+                ? i18n.t("ui.tool.agent.default")
+                : getToolInfo(part.name, currentToolInput(part), currentToolMetadata(part)).title
         counts.set(name, (counts.get(name) ?? 0) + 1)
         return counts
       }, new Map<string, number>()),
@@ -515,15 +528,22 @@ export function CurrentContextToolGroup(props: {
       .join(", "),
   )
   const label = createMemo(() => {
-    const title = names()
+    const notices = props.parts.filter((part) => part.type === "notice").length
+    if (!names() && !notices) {
+      const title = i18n.t("ui.messagePart.context.reasoning")
+      return { text: title, title, before: "", after: "" }
+    }
+    const title = [names(), notices ? i18n.plural("ui.messagePart.context.notice", notices) : undefined]
+      .filter(Boolean)
+      .join(", ")
     const text = i18n.t("ui.messagePart.tools.used", { tools: title })
     const index = text.indexOf(title)
     return { text, title, before: text.slice(0, index).trim(), after: text.slice(index + title.length).trim() }
   })
   const items = createMemo(() =>
-    props.parts.reduce<(SessionMessageAssistantTool[] | (SessionMessageAssistantReasoning & { id: string }))[]>(
+    props.parts.reduce<(SessionMessageAssistantTool[] | Exclude<ContextGroupPart, SessionMessageAssistantTool>)[]>(
       (groups, tool) => {
-        if (tool.type === "reasoning") {
+        if (tool.type !== "tool") {
           groups.push(tool)
           return groups
         }
@@ -556,6 +576,15 @@ export function CurrentContextToolGroup(props: {
       [],
     ),
   )
+  const patchKeys = createMemo(() => {
+    const keys = new Map<SessionMessageAssistantTool, string>()
+    items().forEach((item) => {
+      if (!Array.isArray(item) || item[0]?.name !== "patch" || item[0].state.status === "error") return
+      const key = props.patchGroupKey?.(item) ?? item[0].id
+      item.forEach((tool) => keys.set(tool, key))
+    })
+    return keys
+  })
   const change = (open: boolean) => {
     props.onOpenChange(open)
     props.onSizeChange?.()
@@ -594,19 +623,30 @@ export function CurrentContextToolGroup(props: {
               })
               const reasoning = createMemo(() => {
                 const value = item()
-                return Array.isArray(value) ? undefined : value
+                return !Array.isArray(value) && value.type === "reasoning" ? value : undefined
+              })
+              const callback = createMemo(() => {
+                const value = item()
+                return !Array.isArray(value) && (value.type === "notice" || value.type === "shell") ? value : undefined
               })
               return (
                 <Show
                   when={group()}
                   fallback={
-                    <Show when={reasoning()}>
+                    <Show
+                      when={reasoning()}
+                      fallback={
+                        <Show when={callback()}>
+                          {(part) => <div data-slot="context-tool-group-item">{part().render()}</div>}
+                        </Show>
+                      }
+                    >
                       {(part) => (
                         <div data-slot="context-tool-group-item">
                           <AssistantReasoningContent
                             id={part().id}
                             content={part()}
-                            streaming={false}
+                            streaming={part().streaming ?? false}
                             defaultOpen={props.reasoningDefaultOpen}
                             open={props.reasoningOpen?.(part().id)}
                             onOpenChange={(open) => props.onReasoningOpenChange?.(part().id, open)}
@@ -636,7 +676,8 @@ export function CurrentContextToolGroup(props: {
                           when={
                             tool().state.status !== "error" &&
                             ["read", "glob", "grep", "list"].includes(tool().name) &&
-                            !(tool().name === "read" && readImagePath(currentToolInput(tool())))
+                            !(tool().name === "read" && readImagePath(currentToolInput(tool()))) &&
+                            !currentToolHasLoadedFiles(tool())
                           }
                           fallback={
                             <Show
@@ -653,14 +694,28 @@ export function CurrentContextToolGroup(props: {
                                       output={currentToolOutput(tool())}
                                       error={currentToolError(tool())}
                                       status={tool().state.status}
-                                      defaultOpen={false}
+                                      defaultOpen={props.toolDefaultOpen?.(tool()) ?? false}
+                                      open={props.toolOpen?.(tool().id) ?? props.toolDefaultOpen?.(tool())}
+                                      onOpenChange={(open) => props.onToolOpenChange?.(tool().id, open)}
                                       deferContent
                                       virtualizeDiff={false}
                                       onContentRendered={props.onSizeChange}
                                     />
                                   }
                                 >
-                                  <CurrentFileToolGroup tools={group()} onSizeChange={props.onSizeChange} />
+                                  <CurrentFileToolGroup
+                                    tools={group()}
+                                    fileOpen={
+                                      props.fileOpen &&
+                                      ((path) => props.fileOpen?.(`${patchKeys().get(tool())}:${path}`))
+                                    }
+                                    onFileOpenChange={
+                                      props.onFileOpenChange &&
+                                      ((path, open) =>
+                                        props.onFileOpenChange?.(`${patchKeys().get(tool())}:${path}`, open))
+                                    }
+                                    onSizeChange={props.onSizeChange}
+                                  />
                                 </Show>
                               }
                             >
@@ -1044,19 +1099,7 @@ function toolErrorSubtitle(props: ToolProps, i18n: UiI18n) {
 function toolDisplayError(props: ToolProps & { error?: string }, fallback: string) {
   if (props.status === "error") return props.error
   if (props.tool !== "execute") return undefined
-  const calls = props.metadata.toolCalls
-  const failed =
-    props.metadata.error === true ||
-    (Array.isArray(calls) &&
-      calls.some(
-        (call) =>
-          call !== null &&
-          typeof call === "object" &&
-          !Array.isArray(call) &&
-          "status" in call &&
-          call.status === "error",
-      ))
-  if (!failed) return undefined
+  if (!executeToolFailed(props.metadata)) return undefined
   if (typeof props.output === "string" && props.output) return props.output
   return fallback
 }
diff --git a/packages/ui/src/forms/select/select.tsx b/packages/ui/src/forms/select/select.tsx
index b806975d545..475f0dfead9 100644
--- a/packages/ui/src/forms/select/select.tsx
+++ b/packages/ui/src/forms/select/select.tsx
@@ -181,6 +181,8 @@ export function Select<T>(props: SelectProps<T>) {
     >
       <Trigger
         as="div"
+        aria-label={props["aria-label"]}
+        aria-labelledby={props["aria-labelledby"]}
         data-component="select-v2"
         data-appearance="inline"
         data-invalid={local.invalid ? "" : undefined}
diff --git a/packages/ui/src/i18n/en.ts b/packages/ui/src/i18n/en.ts
index 5c760858597..722abad7ef2 100644
--- a/packages/ui/src/i18n/en.ts
+++ b/packages/ui/src/i18n/en.ts
@@ -108,6 +108,9 @@ const source = {
   "ui.messagePart.context.search.other": "{{count}} searches",
   "ui.messagePart.context.list.one": "{{count}} list",
   "ui.messagePart.context.list.other": "{{count}} lists",
+  "ui.messagePart.context.notice.one": "{{count}} notice",
+  "ui.messagePart.context.notice.other": "{{count}} notices",
+  "ui.messagePart.context.reasoning": "Reasoning",
   "ui.messagePart.context.match.one": "({{count}} match)",
   "ui.messagePart.context.match.other": "({{count}} matches)",
   "ui.messagePart.tools.used": "Used {{tools}}",