diff --git a/packages/session-ui/component-tests/file-tool.spec.ts b/packages/session-ui/component-tests/file-tool.spec.ts
new file mode 100644
index 00000000000..4a207f54680
--- /dev/null
+++ b/packages/session-ui/component-tests/file-tool.spec.ts
@@ -0,0 +1,76 @@
+import { expect, story } from "../../storybook/playwright/story"
+
+for (const theme of ["light", "dark"]) {
+  story(`file tools share Patch's upfront file list in ${theme}`, async ({ mount }, info) => {
+    const root = await mount("current-session-research-agents--agent-research", {
+      args: { scenario: "workflow" },
+      globals: { theme },
+    })
+    const group = root.locator('[data-component="collapsed-tool-group"]').filter({ hasText: "Patch" })
+    const disclosure = group.getByRole("button", { name: /^Used .*Edit.*Write.*Patch$/ })
+    await disclosure.click()
+    for (const name of ["edit", "write", "patch"]) {
+      const tool = group.locator(`[data-timeline-part-id="tool_family_${name}"]`)
+      const file = tool.locator('[data-slot="accordion-trigger"]')
+      await expect(file).toHaveAttribute("aria-expanded", "false")
+      await expect(tool.locator('[data-component="file"]')).toHaveCount(0)
+      await file.click()
+      await expect(file).toHaveAttribute("aria-expanded", "true")
+      await expect(tool.locator('[data-component="file"]')).toBeVisible()
+      await expect(file).toBeFocused()
+      await file.press("Space")
+      await expect(file).toHaveAttribute("aria-expanded", "false")
+      await file.press("Enter")
+      await expect(file).toHaveAttribute("aria-expanded", "true")
+    }
+    await disclosure.click()
+    await disclosure.click()
+    for (const name of ["edit", "write", "patch"]) {
+      const tool = group.locator(`[data-timeline-part-id="tool_family_${name}"]`)
+      await expect(tool.locator('[data-slot="accordion-trigger"]')).toHaveAttribute("aria-expanded", "true")
+      await expect(tool.locator('[data-component="file"]')).toBeVisible()
+    }
+    await root.screenshot({ path: info.outputPath(`file-tools-${theme}.png`) })
+  })
+}
+
+for (const tool of ["edit", "write"]) {
+  for (const controlled of [false, true]) {
+    story(`${tool} supports forceOpen with ${controlled ? "controlled" : "local"} disclosure`, async ({ mount }) => {
+      const root = await mount("current-session-file-changes--file-tool-fallbacks", {
+        args: { tool, controlled, forceOpen: true },
+      })
+      await expect(root.getByRole("button", { name: /example\.ts/ })).toHaveAttribute("aria-expanded", "true")
+      await expect(root.locator('[data-component="file"]')).toBeVisible()
+    })
+  }
+
+  story(`${tool} preserves input fallback and disclosure through completion`, async ({ mount }) => {
+    const root = await mount("current-session-file-changes--file-tool-fallbacks", { args: { tool } })
+    const file = root.getByRole("button", { name: /example\.ts/ })
+    await expect(file).toBeVisible()
+    await expect(file).toHaveAttribute("aria-expanded", "false")
+    await expect(root.getByText("1 file", { exact: true })).toBeVisible()
+    await file.click()
+    await expect(root.locator('[data-component="file"]')).toContainText(tool === "edit" ? "after" : "written")
+    await root.getByRole("button", { name: "Complete file tool" }).click()
+    await expect(root.getByText("Example diagnostic")).toBeVisible()
+    await expect(file).toHaveAttribute("aria-expanded", "true")
+    await file.click()
+    await expect(file).toHaveAttribute("aria-expanded", "false")
+    await expect(root.getByText("Example diagnostic")).toBeVisible()
+  })
+}
+
+story("empty writes still show a file row", async ({ mount }) => {
+  const root = await mount("current-session-file-changes--file-tool-fallbacks", {
+    args: { tool: "write", empty: true },
+  })
+  await root.getByRole("button", { name: "Complete file tool" }).click()
+  const file = root.getByRole("button", { name: /example\.ts/ })
+  await expect(file).toHaveAttribute("aria-expanded", "false")
+  await file.click()
+  await expect(file).toHaveAttribute("aria-expanded", "true")
+  await expect(root.locator('[data-component="file"]')).toBeAttached()
+  await expect(file).toBeVisible()
+})
diff --git a/packages/session-ui/component-tests/session-tool-projection.spec.ts b/packages/session-ui/component-tests/session-tool-projection.spec.ts
index dd54558d0f0..a898dfd847d 100644
--- a/packages/session-ui/component-tests/session-tool-projection.spec.ts
+++ b/packages/session-ui/component-tests/session-tool-projection.spec.ts
@@ -25,18 +25,17 @@ story("renders every admitted tool family and hides timeline-only exclusions", a
   ]) {
     await expect(timeline.locator(`[data-timeline-part-id="tool_family_${id}"]`), id).toBeVisible()
   }
-  const patch = timeline.locator('[data-timeline-part-id="tool_family_patch"]')
-  await expect(patch.getByText("1 file", { exact: true })).toBeVisible()
-  await expect(patch.getByRole("button", { name: "Patch 1 file", exact: true })).toHaveCount(0)
-  await expect(patch.getByRole("button")).toHaveCount(1)
-  await expect(patch.locator('[data-scope="apply-patch"] button')).toHaveAttribute("aria-expanded", "false")
-  await expect(patch.locator('[data-slot="message-part-title-filename"]')).toHaveCount(0)
-  await expect(patch.locator('[data-slot="message-part-actions"]')).toHaveCount(0)
-  await expect(patch.locator('[data-slot="basic-tool-tool-title"]')).toHaveCSS("font-size", "13px")
-  const edit = timeline.locator('[data-timeline-part-id="tool_family_edit"]')
-  await expect(edit).toContainText("Edit")
-  await expect(edit.locator('[data-slot="message-part-title"]')).toHaveCSS("font-size", "13px")
-  await expect(edit.locator('[data-slot="message-part-title"]')).toHaveCSS("line-height", "16px")
+  for (const name of ["edit", "write", "patch"]) {
+    const tool = timeline.locator(`[data-timeline-part-id="tool_family_${name}"]`)
+    await expect(tool.getByText("1 file", { exact: true })).toBeVisible()
+    await expect(tool.getByRole("button")).toHaveCount(1)
+    await expect(tool.locator('[data-scope="apply-patch"] button')).toHaveAttribute("aria-expanded", "false")
+    await expect(tool.locator('[data-slot="collapsible-trigger"]')).toHaveAttribute("data-locked", "")
+    await expect(tool.locator('[data-slot="message-part-title-filename"]')).toHaveCount(0)
+    await expect(tool.locator('[data-slot="message-part-actions"]')).toHaveCount(0)
+    await expect(tool.locator('[data-slot="basic-tool-tool-title"]')).toHaveCSS("font-size", "13px")
+    await expect(tool.locator('[data-slot="basic-tool-tool-title"]')).toHaveCSS("line-height", "16px")
+  }
   await expect(timeline.locator('[data-timeline-part-id="tool_family_todo"]')).toHaveCount(0)
 })
 
diff --git a/packages/session-ui/src/components/message-part.css b/packages/session-ui/src/components/message-part.css
index a6626e94c84..eeebe0fab7d 100644
--- a/packages/session-ui/src/components/message-part.css
+++ b/packages/session-ui/src/components/message-part.css
@@ -466,102 +466,6 @@
   --tool-content-gap: 8px;
 }
 
-[data-component="edit-trigger"],
-[data-component="write-trigger"] {
-  display: flex;
-  align-items: center;
-  justify-content: space-between;
-  gap: 12px;
-  width: 100%;
-
-  [data-slot="message-part-title-area"] {
-    flex-grow: 1;
-    display: flex;
-    align-items: center;
-    gap: 8px;
-    min-width: 0;
-  }
-
-  [data-slot="message-part-title"] {
-    flex: 1 1 auto;
-    display: flex;
-    align-items: center;
-    gap: 8px;
-    min-width: 0;
-    font-family: var(--font-family-sans);
-    font-size: 13px;
-    font-style: normal;
-    font-weight: var(--font-weight-medium);
-    line-height: var(--line-height-compact);
-    letter-spacing: var(--letter-spacing-normal);
-    color: var(--v2-text-text-muted);
-  }
-
-  [data-slot="message-part-title-spinner"] {
-    margin-left: 4px;
-    width: 16px;
-    height: 16px;
-    display: inline-flex;
-    align-items: center;
-    justify-content: center;
-    flex-shrink: 0;
-    color: var(--v2-text-text-muted);
-
-    [data-component="spinner"] {
-      width: 16px;
-      height: 16px;
-    }
-  }
-
-  [data-slot="message-part-title-text"] {
-    flex-shrink: 0;
-    text-transform: capitalize;
-    color: var(--v2-text-text-base);
-  }
-
-  [data-slot="message-part-title-filename"] {
-    /* No text-transform - preserve original filename casing */
-    min-width: 0;
-    overflow: hidden;
-    text-overflow: ellipsis;
-    white-space: nowrap;
-    font-weight: var(--font-weight-regular);
-    direction: ltr;
-    unicode-bidi: isolate;
-  }
-
-  [data-slot="message-part-path"] {
-    display: flex;
-    flex-grow: 1;
-    min-width: 0;
-    font-weight: var(--font-weight-regular);
-    direction: ltr;
-    unicode-bidi: isolate;
-  }
-
-  [data-slot="message-part-directory"] {
-    color: var(--v2-text-text-muted);
-    text-overflow: ellipsis;
-    overflow: hidden;
-    white-space: nowrap;
-    direction: rtl;
-    text-align: left;
-  }
-
-  [data-slot="message-part-filename"] {
-    color: var(--v2-text-text-base);
-    flex-shrink: 0;
-  }
-
-  [data-slot="message-part-actions"] {
-    display: flex;
-    gap: 16px;
-    align-items: center;
-    justify-content: flex-end;
-    flex-shrink: 0;
-  }
-}
-
 [data-component="edit-content"] {
   border-radius: inherit;
   border-top: 0.5px solid var(--v2-border-border-muted);
diff --git a/packages/session-ui/src/timeline/file-changes.stories.tsx b/packages/session-ui/src/timeline/file-changes.stories.tsx
index 96e2f27c412..b9445a0e46d 100644
--- a/packages/session-ui/src/timeline/file-changes.stories.tsx
+++ b/packages/session-ui/src/timeline/file-changes.stories.tsx
@@ -11,6 +11,7 @@ import {
 } from "../storybook/current-session-fixtures"
 import { storyDocument, storyPatchFile, storyTool } from "../storybook/current-session-scenarios"
 import { SessionTimeline } from "./session-timeline"
+import { ToolDisplay } from "../tools/tool-renderer"
 
 export default {
   title: "OpenCode/Work/File changes",
@@ -261,3 +262,48 @@ export const CreatedANewFile = {
     />
   ),
 }
+
+export const FileToolFallbacks = {
+  args: { tool: "edit", empty: false, forceOpen: false, controlled: true },
+  argTypes: {
+    tool: { control: "select", options: ["edit", "write"] },
+    empty: { control: "boolean" },
+    forceOpen: { control: "boolean" },
+    controlled: { control: "boolean" },
+  },
+  render: (args: { tool: string; empty: boolean; forceOpen: boolean; controlled: boolean }) => {
+    const [state, setState] = createStore({ completed: false, open: false })
+    return (
+      <section class="mx-auto flex w-full max-w-[860px] flex-col gap-4 p-6">
+        <button type="button" onClick={() => setState("completed", true)}>
+          Complete file tool
+        </button>
+        <CurrentSessionProviders document={storyDocument([])}>
+          <ToolDisplay
+            id="tool_file_fallback"
+            tool={args.tool}
+            status={state.completed ? "completed" : "running"}
+            input={{
+              path: "src/example.ts",
+              oldString: "export const before = true\n",
+              newString: "export const after = true\n",
+              content: args.empty ? "" : "export const written = true\n",
+            }}
+            metadata={{
+              diagnostics: state.completed
+                ? {
+                    "src/example.ts": [
+                      { severity: 1, message: "Example diagnostic", range: { start: { line: 0, character: 0 } } },
+                    ],
+                  }
+                : {},
+            }}
+            open={args.controlled ? state.open : undefined}
+            onOpenChange={(open) => setState("open", open)}
+            forceOpen={args.forceOpen}
+          />
+        </CurrentSessionProviders>
+      </section>
+    )
+  },
+}
diff --git a/packages/session-ui/src/tools/tool-renderer.tsx b/packages/session-ui/src/tools/tool-renderer.tsx
index 9c0506f6c0c..a672949ec24 100644
--- a/packages/session-ui/src/tools/tool-renderer.tsx
+++ b/packages/session-ui/src/tools/tool-renderer.tsx
@@ -951,20 +951,66 @@ export const ToolRegistry = {
   render: getTool,
 }
 
+function FileTool(props: ToolProps & { title: string; count: number; children: JSX.Element }) {
+  const i18n = useI18n()
+  return (
+    <BasicTool
+      {...props}
+      open
+      onOpenChange={undefined}
+      locked
+      icon="code-lines"
+      defer={false}
+      rail={false}
+      trigger={{
+        title: props.title,
+        subtitle: props.count > 0 ? `${props.count} ${i18n.plural("ui.common.file", props.count)}` : "",
+      }}
+    >
+      {props.children}
+    </BasicTool>
+  )
+}
+
 function ToolFileAccordion(props: {
   path: string
   actions?: JSX.Element
   children: JSX.Element
   defaultOpen?: boolean
+  open?: boolean
+  onOpenChange?: (open: boolean) => void
+  forceOpen?: boolean
+  defer?: boolean
 }) {
   const value = createMemo(() => props.path || "tool-file")
+  const [expanded, setExpanded] = createSignal(props.defaultOpen ?? false)
+  const [visible, setVisible] = createSignal(false)
+  const open = () => props.open ?? expanded()
+  const change = (value: boolean) => {
+    if (props.open === undefined) setExpanded(value)
+    props.onOpenChange?.(value)
+  }
+
+  createEffect(() => {
+    if (props.forceOpen && !open()) change(true)
+  })
+
+  createEffect(() => {
+    if (!open()) {
+      setVisible(false)
+      return
+    }
+    const frame = requestAnimationFrame(() => setVisible(true))
+    onCleanup(() => cancelAnimationFrame(frame))
+  })
 
   return (
     <Accordion
       multiple
       data-scope="apply-patch"
       style={{ "--sticky-accordion-offset": "calc(32px + var(--tool-content-gap))" }}
-      defaultValue={props.defaultOpen === false ? [] : [value()]}
+      value={open() ? [value()] : []}
+      onChange={(next) => change(next.includes(value()))}
     >
       <Accordion.Item value={value()}>
         <StickyAccordionHeader>
@@ -986,7 +1032,9 @@ function ToolFileAccordion(props: {
             </div>
           </Accordion.Trigger>
         </StickyAccordionHeader>
-        <Accordion.Content>{props.children}</Accordion.Content>
+        <Accordion.Content>
+          <Show when={!props.defer || visible()}>{props.children}</Show>
+        </Accordion.Content>
       </Accordion.Item>
     </Accordion>
   )
@@ -1709,7 +1757,6 @@ ToolRegistry.register({
       const value = diff()
       return typeof value?.file === "string" ? value.file : inputPath()
     })
-    const filename = () => getFilename(inputPath())
     const pending = () => props.status === "streaming" || props.status === "running"
     const diffSource = createMemo(
       () => {
@@ -1749,39 +1796,15 @@ ToolRegistry.register({
 
     return (
       <div data-component="edit-tool">
-        <BasicTool
-          {...props}
-          icon="code-lines"
-          rail={false}
-          defer={props.deferContent !== false}
-          trigger={
-            <div data-component="edit-trigger">
-              <div data-slot="message-part-title-area">
-                <div data-slot="message-part-title">
-                  <span data-slot="message-part-title-text">
-                    <TextShimmer text={i18n.t("ui.messagePart.title.edit")} active={pending()} />
-                  </span>
-                  <Show when={!pending()}>
-                    <span data-slot="message-part-title-filename">{filename()}</span>
-                  </Show>
-                </div>
-                <Show when={!pending() && inputPath().includes("/")}>
-                  <div data-slot="message-part-path">
-                    <span data-slot="message-part-directory">{displayDirectory(inputPath())}</span>
-                  </div>
-                </Show>
-              </div>
-              <div data-slot="message-part-actions">
-                <Show when={!pending() ? diff() : undefined}>
-                  {(diff) => <DiffChanges appearance="standard" changes={diff()} />}
-                </Show>
-              </div>
-            </div>
-          }
-        >
+        <FileTool {...props} title={i18n.t("ui.messagePart.title.edit")} count={path() ? 1 : 0}>
           <Show when={path()}>
             <ToolFileAccordion
               path={path()}
+              defaultOpen={props.defaultOpen}
+              open={props.open}
+              onOpenChange={props.onOpenChange}
+              forceOpen={props.forceOpen}
+              defer={props.deferContent !== false}
               actions={
                 <Show when={!pending() ? diff() : undefined}>
                   {(diff) => <DiffChanges appearance="standard" changes={diff()} />}
@@ -1800,7 +1823,7 @@ ToolRegistry.register({
             </ToolFileAccordion>
           </Show>
           <DiagnosticsDisplay diagnostics={diagnostics()} />
-        </BasicTool>
+        </FileTool>
       </div>
     )
   },
@@ -1814,38 +1837,18 @@ ToolRegistry.register({
     const path = createMemo(() => (typeof props.input.path === "string" ? props.input.path : ""))
     const content = createMemo(() => (typeof props.input.content === "string" ? props.input.content : ""))
     const diagnostics = createMemo(() => getDiagnostics(props.metadata.diagnostics, path()))
-    const filename = () => getFilename(path())
-    const pending = () => props.status === "streaming" || props.status === "running"
     return (
       <div data-component="write-tool">
-        <BasicTool
-          {...props}
-          icon="code-lines"
-          rail={false}
-          defer={props.deferContent !== false}
-          trigger={
-            <div data-component="write-trigger">
-              <div data-slot="message-part-title-area">
-                <div data-slot="message-part-title">
-                  <span data-slot="message-part-title-text">
-                    <TextShimmer text={i18n.t("ui.messagePart.title.write")} active={pending()} />
-                  </span>
-                  <Show when={!pending()}>
-                    <span data-slot="message-part-title-filename">{filename()}</span>
-                  </Show>
-                </div>
-                <Show when={!pending() && path().includes("/")}>
-                  <div data-slot="message-part-path">
-                    <span data-slot="message-part-directory">{displayDirectory(path())}</span>
-                  </div>
-                </Show>
-              </div>
-              <div data-slot="message-part-actions">{/* <DiffChanges diff={diff} /> */}</div>
-            </div>
-          }
-        >
-          <Show when={content() && path()}>
-            <ToolFileAccordion path={path()}>
+        <FileTool {...props} title={i18n.t("ui.messagePart.title.write")} count={path() ? 1 : 0}>
+          <Show when={path()}>
+            <ToolFileAccordion
+              path={path()}
+              defaultOpen={props.defaultOpen}
+              open={props.open}
+              onOpenChange={props.onOpenChange}
+              forceOpen={props.forceOpen}
+              defer={props.deferContent !== false}
+            >
               <div data-component="write-content">
                 <Dynamic
                   component={fileComponent}
@@ -1862,7 +1865,7 @@ ToolRegistry.register({
             </ToolFileAccordion>
           </Show>
           <DiagnosticsDisplay diagnostics={diagnostics()} />
-        </BasicTool>
+        </FileTool>
       </div>
     )
   },
@@ -1891,27 +1894,9 @@ ToolRegistry.register({
       files().forEach((file) => props.onFileOpenChange?.(file.path, next.includes(file.path)))
     }
 
-    const subtitle = createMemo(() => {
-      const count = files().length
-      if (count === 0) return ""
-      return `${count} ${i18n.plural("ui.common.file", count)}`
-    })
-
     return (
       <div data-component="apply-patch-tool">
-        <BasicTool
-          {...props}
-          open
-          onOpenChange={undefined}
-          locked
-          icon="code-lines"
-          defer={false}
-          rail={false}
-          trigger={{
-            title: title(),
-            subtitle: subtitle(),
-          }}
-        >
+        <FileTool {...props} title={title()} count={files().length}>
           <Show when={files().length > 0}>
             <Accordion
               multiple
@@ -2000,7 +1985,7 @@ ToolRegistry.register({
               </Index>
             </Accordion>
           </Show>
-        </BasicTool>
+        </FileTool>
       </div>
     )
   },