diff --git a/packages/core/src/codemode/instructions.ts b/packages/core/src/codemode/instructions.ts
index 95e9f5338dc..0934a4a953a 100644
--- a/packages/core/src/codemode/instructions.ts
+++ b/packages/core/src/codemode/instructions.ts
@@ -1,45 +1,24 @@
 export * as CodeModeInstructions from "./instructions"
 
-import { Context, Effect, Layer, Schema } from "effect"
-import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
-import { AgentV2 } from "../agent"
-import { CodeMode } from "../codemode"
+import { Effect, Schema } from "effect"
 import { Instructions } from "../instructions/index"
 
-export interface Interface {
-  readonly load: (agent: AgentV2.Selection) => Effect.Effect<Instructions.Instructions>
+const key = Instructions.Key.make("core/codemode")
+const codec = Schema.toCodecJson(Schema.String)
+const render = {
+  initial: (current: string) => current,
+  changed: (_previous: string, current: string) =>
+    [
+      "The Code Mode tool catalog has changed. This catalog supersedes the previous Code Mode tool catalog.",
+      current,
+    ].join("\n\n"),
+  removed: () => "Code Mode tools are no longer available. Do not use any previously listed Code Mode tools.",
 }
 
-export class Service extends Context.Service<Service, Interface>()("@opencode/v2/CodeModeInstructions") {}
-
-const layer = Layer.effect(
-  Service,
-  Effect.gen(function* () {
-    const codeMode = yield* CodeMode.Service
-
-    return Service.of({
-      load: Effect.fn("CodeModeInstructions.load")(function* (selection) {
-        const instructions = selection.info
-          ? (yield* codeMode.materialize(selection.info.permissions)).instructions
-          : undefined
-        return Instructions.make({
-          key: Instructions.Key.make("core/codemode"),
-          codec: Schema.toCodecJson(Schema.String),
-          read: Effect.succeed(instructions ?? Instructions.removed),
-          render: {
-            initial: (current) => current,
-            changed: (_previous, current) =>
-              [
-                "The Code Mode tool catalog has changed. This catalog supersedes the previous Code Mode tool catalog.",
-                current,
-              ].join("\n\n"),
-            removed: () =>
-              "Code Mode tools are no longer available. Do not use any previously listed Code Mode tools.",
-          },
-        })
-      }),
-    })
-  }),
-)
-
-export const node = makeLocationNode({ service: Service, layer, deps: [CodeMode.node] })
+export const make = (content?: string): Instructions.Instructions =>
+  Instructions.make({
+    key,
+    codec,
+    read: Effect.succeed(content ?? Instructions.removed),
+    render,
+  })
diff --git a/packages/core/src/location-services.ts b/packages/core/src/location-services.ts
index adf1afe62be..5208f6a7cc5 100644
--- a/packages/core/src/location-services.ts
+++ b/packages/core/src/location-services.ts
@@ -3,7 +3,6 @@ import { AgentV2 } from "./agent"
 import { AISDK } from "./aisdk"
 import { Catalog } from "./catalog"
 import { CodeMode } from "./codemode"
-import { CodeModeInstructions } from "./codemode/instructions"
 import { CommandV2 } from "./command"
 import { Config } from "./config"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
@@ -82,7 +81,6 @@ const locationServiceNodes = [
   ToolRegistry.toolsNode,
   Image.node,
   SkillInstructions.node,
-  CodeModeInstructions.node,
   ReferenceInstructions.node,
   InstructionEntry.node,
   Form.node,
diff --git a/packages/core/src/session/context.ts b/packages/core/src/session/context.ts
index d025ca8dce2..be3d9bb08f8 100644
--- a/packages/core/src/session/context.ts
+++ b/packages/core/src/session/context.ts
@@ -2,6 +2,7 @@ export * as SessionContext from "./context"
 
 import { Context, Effect, Layer } from "effect"
 import { AgentV2 } from "../agent"
+import { CodeModeInstructions } from "../codemode/instructions"
 import { Database } from "../database/database"
 import { makeLocationNode } from "@opencode-ai/util/effect/app-node"
 import { InstructionDiscovery } from "../instruction-discovery"
@@ -12,7 +13,7 @@ import { McpInstructions } from "../mcp/instructions"
 import { PluginSupervisor } from "../plugin/supervisor"
 import { ReferenceInstructions } from "../reference/instructions"
 import { SkillInstructions } from "../skill/instructions"
-import { CodeModeInstructions } from "../codemode/instructions"
+import { ToolRegistry } from "../tool/registry"
 import { AgentNotFoundError } from "./error"
 import { SessionHistory } from "./history"
 import { InstructionEntry } from "./instruction-entry"
@@ -25,6 +26,7 @@ export interface Selection {
   readonly session: SessionSchema.Info
   readonly agent: AgentV2.Selection & { readonly info: AgentV2.Info }
   readonly instructions: Instructions.Instructions
+  readonly toolSet: ToolRegistry.ToolSet
 }
 
 export interface Loaded {
@@ -33,15 +35,17 @@ export interface Loaded {
   readonly model: SessionRunnerModel.Resolved
   readonly initial: string
   readonly messages: ReadonlyArray<SessionMessage.Info>
+  readonly toolSet: ToolRegistry.ToolSet
 }
 
 /**
  * Resolves model-request state in two phases: `select` fixes the Session,
- * agent, and instruction sources; `load` adds the model and active history for
- * that selection. This module does not build or execute the model request.
+ * agent, instruction sources, and tool snapshot; `load` adds the model and
+ * active history for that selection. This module does not build or execute the
+ * model request.
  */
 export interface Interface {
-  /** Selects the Session, agent, and instruction sources used by subsequent work. */
+  /** Selects the Session, agent, instructions, and tools used by subsequent work. */
   readonly select: (sessionID: SessionSchema.ID) => Effect.Effect<Selection, AgentNotFoundError>
   /** Resolves the model and active history for that selection. */
   readonly load: (selection: Selection) => Effect.Effect<Loaded, SessionRunnerModel.Error>
@@ -55,7 +59,6 @@ const layer = Layer.effect(
   Effect.gen(function* () {
     const agents = yield* AgentV2.Service
     const builtins = yield* InstructionBuiltIns.Service
-    const codeModeInstructions = yield* CodeModeInstructions.Service
     const db = (yield* Database.Service).db
     const discovery = yield* InstructionDiscovery.Service
     const entries = yield* InstructionEntry.Service
@@ -66,6 +69,7 @@ const layer = Layer.effect(
     const referenceInstructions = yield* ReferenceInstructions.Service
     const skillInstructions = yield* SkillInstructions.Service
     const store = yield* SessionStore.Service
+    const registry = yield* ToolRegistry.Service
 
     const select = Effect.fn("SessionContext.select")(function* (sessionID: SessionSchema.ID) {
       const session = yield* store.get(sessionID)
@@ -76,19 +80,32 @@ const layer = Layer.effect(
       yield* plugins.flush
       const agent = yield* agents.select(session.agent)
       if (!agent.info) return yield* new AgentNotFoundError({ sessionID: session.id, agent: session.agent ?? agent.id })
-      const instructions = yield* Effect.all(
-        [
-          builtins.load(sessionID),
-          codeModeInstructions.load(agent),
-          discovery.load(),
-          skillInstructions.load(agent),
-          referenceInstructions.load(),
-          mcpInstructions.load(agent),
-          entries.load(sessionID),
-        ],
+      const loaded = yield* Effect.all(
+        {
+          toolSet: registry.snapshot(agent.info.permissions),
+          builtins: builtins.load(sessionID),
+          discovery: discovery.load(),
+          skills: skillInstructions.load(agent),
+          references: referenceInstructions.load(),
+          mcp: mcpInstructions.load(agent),
+          entries: entries.load(sessionID),
+        },
         { concurrency: "unbounded" },
-      ).pipe(Effect.map(Instructions.combine))
-      return { session, agent: { ...agent, info: agent.info }, instructions }
+      )
+      return {
+        session,
+        agent: { ...agent, info: agent.info },
+        instructions: Instructions.combine([
+          loaded.builtins,
+          CodeModeInstructions.make(loaded.toolSet.codeModeInstructions),
+          loaded.discovery,
+          loaded.skills,
+          loaded.references,
+          loaded.mcp,
+          loaded.entries,
+        ]),
+        toolSet: loaded.toolSet,
+      }
     })
 
     const load = Effect.fn("SessionContext.load")(function* (selection: Selection) {
@@ -100,6 +117,7 @@ const layer = Layer.effect(
         model,
         initial: history.initial,
         messages: history.entries.map((entry) => entry.message),
+        toolSet: selection.toolSet,
       }
     })
 
@@ -112,7 +130,6 @@ export const node = makeLocationNode({
   layer,
   deps: [
     AgentV2.node,
-    CodeModeInstructions.node,
     Database.node,
     InstructionBuiltIns.node,
     InstructionDiscovery.node,
@@ -124,5 +141,6 @@ export const node = makeLocationNode({
     SessionRunnerModel.node,
     SessionStore.node,
     SkillInstructions.node,
+    ToolRegistry.node,
   ],
 })
diff --git a/packages/core/src/session/generate-node.ts b/packages/core/src/session/generate-node.ts
index 0158760c3bf..e1b81c22b91 100644
--- a/packages/core/src/session/generate-node.ts
+++ b/packages/core/src/session/generate-node.ts
@@ -12,7 +12,6 @@ import { SessionGenerate } from "./generate"
 import { SessionHistory } from "./history"
 import { SessionModelHeaders } from "./model-headers"
 import { SessionRunnerModel } from "./runner/model"
-import { ToolRegistry } from "../tool/registry"
 import PROMPT_DEFAULT from "./runner/prompt/base.txt"
 import { toLLMMessages } from "./runner/to-llm-message"
 
@@ -24,7 +23,6 @@ export const layer = Layer.effect(
     const hooks = yield* PluginHooks.Service
     const llm = yield* LLMClient.Service
     const models = yield* SessionRunnerModel.Service
-    const registry = yield* ToolRegistry.Service
     const app = yield* App.Metadata
 
     return SessionGenerate.Service.of({
@@ -36,7 +34,7 @@ export const layer = Layer.effect(
         const promptCacheKey = /^ses_[0-9a-f]{64}$/.test(selection.session.id)
           ? selection.session.id.slice(4)
           : selection.session.id
-        const toolSet = yield* registry.snapshot(selection.agent.info.permissions)
+        const toolSet = selection.toolSet
         const toolDefinitions = toolSet.definitions
         const toolsByName = new Map(toolDefinitions.map((tool) => [tool.name, tool]))
         const contextEvent = yield* hooks.trigger("session", "context", {
@@ -89,13 +87,5 @@ export const layer = Layer.effect(
 export const node = makeLocationNode({
   service: SessionGenerate.Service,
   layer,
-  deps: [
-    SessionContext.node,
-    Database.node,
-    PluginHooks.node,
-    SessionRunnerModel.node,
-    ToolRegistry.node,
-    App.node,
-    llmClient,
-  ],
+  deps: [SessionContext.node, Database.node, PluginHooks.node, SessionRunnerModel.node, App.node, llmClient],
 })
diff --git a/packages/core/src/session/model-request.ts b/packages/core/src/session/model-request.ts
index f7fcb95adb0..af9ac71a864 100644
--- a/packages/core/src/session/model-request.ts
+++ b/packages/core/src/session/model-request.ts
@@ -86,7 +86,6 @@ export const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
     const hooks = yield* PluginHooks.Service
-    const registry = yield* ToolRegistry.Service
     const app = yield* App.Metadata
 
     const prepare = Effect.fn("SessionModelRequest.prepare")(function* (input: PrepareInput) {
@@ -98,7 +97,7 @@ export const layer = Layer.effect(
       const stepLimitReached = agent.info.steps !== undefined && input.step >= agent.info.steps
       // The final Step keeps definitions available to protocols with native "none",
       // preserving their prompt cache prefix. Calls are still rejected at execution.
-      const toolSet = yield* registry.snapshot(agent.info.permissions)
+      const toolSet = input.context.toolSet
       const promptCacheKey = /^ses_[0-9a-f]{64}$/.test(session.id) ? session.id.slice(4) : session.id
       const system = [agent.info.system ? agent.info.system : PROMPT_DEFAULT, input.context.initial]
         .filter((part) => part.length > 0)
@@ -162,5 +161,5 @@ export const layer = Layer.effect(
 export const node = makeLocationNode({
   service: Service,
   layer,
-  deps: [PluginHooks.node, ToolRegistry.node, App.node],
+  deps: [PluginHooks.node, App.node],
 })
diff --git a/packages/core/src/tool/registry.ts b/packages/core/src/tool/registry.ts
index 6688c7ef01d..c572541a948 100644
--- a/packages/core/src/tool/registry.ts
+++ b/packages/core/src/tool/registry.ts
@@ -44,12 +44,13 @@ export interface Interface {
 }
 
 /**
- * One request-scoped snapshot pairing advertised definitions with captured
- * tools. A model request executes exactly the tool values it advertised
- * even if registration changes while the request is in flight.
+ * One request-scoped snapshot pairing Code Mode instructions and advertised
+ * definitions with captured tools. A model request executes exactly the tool
+ * values it advertised even if registration changes while it is in flight.
  */
 export interface ToolSet {
   readonly definitions: ReadonlyArray<ToolDefinition>
+  readonly codeModeInstructions?: string
   readonly execute: (input: ExecuteInput) => Effect.Effect<ToolOutcome, ToolOutputStore.Error>
 }
 
@@ -320,8 +321,12 @@ const registryLayer = Layer.effect(
               if (whollyDisabled(registration.permission, rules)) continue
               direct.set(name, registration)
             }
-            const codemodeTool = (yield* codeMode.materialize(permissions)).tool
+            const codeModeMaterialization = yield* codeMode.materialize(permissions)
+            const codemodeTool = codeModeMaterialization.tool
             return {
+              ...(codeModeMaterialization.instructions === undefined
+                ? {}
+                : { codeModeInstructions: codeModeMaterialization.instructions }),
               definitions: [
                 // Definitions are prompt-cache prefix bytes, so order only after effective registrations settle.
                 ...Array.from(direct)
diff --git a/packages/core/test/codemode/instructions.test.ts b/packages/core/test/codemode/instructions.test.ts
index c47f35766c4..6c8bc790769 100644
--- a/packages/core/test/codemode/instructions.test.ts
+++ b/packages/core/test/codemode/instructions.test.ts
@@ -1,15 +1,12 @@
 import { describe, expect } from "bun:test"
-import { AgentV2 } from "@opencode-ai/core/agent"
 import { CodeMode } from "@opencode-ai/core/codemode"
 import { CodeModeInstructions } from "@opencode-ai/core/codemode/instructions"
 import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
 import { Tool } from "@opencode-ai/core/tool/tool"
-import { Effect, Layer, Schema } from "effect"
+import { Effect, Schema } from "effect"
 import { it } from "../lib/effect"
 import { readInitial, readUpdate } from "../lib/instructions"
 
-const agent = AgentV2.Info.make(AgentV2.Info.empty(AgentV2.ID.make("build")))
-
 describe("CodeModeInstructions", () => {
   it.effect("treats equivalent registration orders as an instruction no-op", () => {
     const alpha = Tool.make({
@@ -24,70 +21,46 @@ describe("CodeModeInstructions", () => {
       output: Schema.String,
       execute: () => Effect.succeed({ output: "zeta" }),
     })
-
     const codeModeLayer = AppNodeBuilder.build(CodeMode.node)
-    const layer = Layer.merge(
-      codeModeLayer,
-      AppNodeBuilder.build(CodeModeInstructions.node, [[CodeMode.node, codeModeLayer]]),
-    )
 
     return Effect.gen(function* () {
       const codeMode = yield* CodeMode.Service
-      const instructions = yield* CodeModeInstructions.Service
       const initialized = yield* Effect.scoped(
         Effect.gen(function* () {
           yield* codeMode.register(Tool.registrationEntries({ zeta, alpha }, { namespace: "tools" }))
-          return yield* instructions.load({ id: agent.id, info: agent }).pipe(Effect.flatMap(readInitial))
+          const materialization = yield* codeMode.materialize()
+          return yield* readInitial(CodeModeInstructions.make(materialization.instructions))
         }),
       )
       const reordered = yield* Effect.scoped(
         Effect.gen(function* () {
           yield* codeMode.register(Tool.registrationEntries({ alpha, zeta }, { namespace: "tools" }))
-          return yield* instructions
-            .load({ id: agent.id, info: agent })
-            .pipe(Effect.flatMap((context) => readUpdate(context, initialized)))
+          const materialization = yield* codeMode.materialize()
+          return yield* readUpdate(CodeModeInstructions.make(materialization.instructions), initialized)
         }),
       )
 
       expect(reordered.changed).toBe(false)
       expect(reordered.text).toBe("")
-    }).pipe(Effect.provide(layer))
+    }).pipe(Effect.provide(codeModeLayer))
   })
 
   it.effect("renders catalog changes and removal", () => {
     let catalog: string | undefined = "Initial Code Mode catalog"
-    const layer = AppNodeBuilder.build(CodeModeInstructions.node, [
-      [
-        CodeMode.node,
-        Layer.mock(CodeMode.Service, {
-          materialize: () => Effect.succeed({ ...(catalog === undefined ? {} : { instructions: catalog }) }),
-          register: () => Effect.void,
-        }),
-      ],
-    ])
 
     return Effect.gen(function* () {
-      const instructions = yield* CodeModeInstructions.Service
-      const initialized = yield* instructions.load({ id: agent.id, info: agent }).pipe(Effect.flatMap(readInitial))
+      const initialized = yield* readInitial(CodeModeInstructions.make(catalog))
       expect(initialized.text).toBe("Initial Code Mode catalog")
 
       catalog = "Updated Code Mode catalog"
-      expect(
-        yield* instructions
-          .load({ id: agent.id, info: agent })
-          .pipe(Effect.flatMap((context) => readUpdate(context, initialized))),
-      ).toMatchObject({
+      expect(yield* readUpdate(CodeModeInstructions.make(catalog), initialized)).toMatchObject({
         text: "The Code Mode tool catalog has changed. This catalog supersedes the previous Code Mode tool catalog.\n\nUpdated Code Mode catalog",
       })
 
       catalog = undefined
-      expect(
-        yield* instructions
-          .load({ id: agent.id, info: agent })
-          .pipe(Effect.flatMap((context) => readUpdate(context, initialized))),
-      ).toMatchObject({
+      expect(yield* readUpdate(CodeModeInstructions.make(catalog), initialized)).toMatchObject({
         text: "Code Mode tools are no longer available. Do not use any previously listed Code Mode tools.",
       })
-    }).pipe(Effect.provide(layer))
+    })
   })
 })
diff --git a/packages/core/test/location-layer.test.ts b/packages/core/test/location-layer.test.ts
index 44a572f138d..1a198371ece 100644
--- a/packages/core/test/location-layer.test.ts
+++ b/packages/core/test/location-layer.test.ts
@@ -578,7 +578,8 @@ describe("LocationServiceMap", () => {
           const blockedState = yield* update(blocked.path, blockedID)
           expect(blockedState.providers.some((provider) => provider.id === blockedID)).toBe(true)
           expect(blockedState.providers.some((provider) => provider.id === allowedID)).toBe(false)
-          expect(blockedState.tools.map((tool) => tool.name).sort()).toEqual([
+          const blockedTools = blockedState.tools.map((tool) => tool.name)
+          expect(blockedTools.filter((name) => name !== "execute").sort()).toEqual([
             "edit",
             "glob",
             "grep",
@@ -595,7 +596,9 @@ describe("LocationServiceMap", () => {
           const allowedState = yield* update(allowed.path, allowedID)
           expect(allowedState.providers.some((provider) => provider.id === allowedID)).toBe(true)
           expect(allowedState.providers.some((provider) => provider.id === blockedID)).toBe(false)
-          expect(allowedState.tools.map((tool) => tool.name).sort()).toEqual([
+          const allowedTools = allowedState.tools.map((tool) => tool.name)
+          expect(blockedTools.includes("execute")).toBe(allowedTools.includes("execute"))
+          expect(allowedTools.filter((name) => name !== "execute").sort()).toEqual([
             "edit",
             "glob",
             "grep",
diff --git a/packages/core/test/session-generate.test.ts b/packages/core/test/session-generate.test.ts
index b53dcb826dc..20b0ca07fe3 100644
--- a/packages/core/test/session-generate.test.ts
+++ b/packages/core/test/session-generate.test.ts
@@ -97,6 +97,7 @@ const plugins = Layer.mock(PluginSupervisor.Service, { flush: Effect.void })
 const tools = Layer.mock(ToolRegistry.Service, {
   snapshot: () =>
     Effect.succeed({
+      codeModeInstructions: "Captured Code Mode catalog",
       definitions: [ToolDefinition.make({ name: "lookup", description: "Lookup", inputSchema: { type: "object" } })],
       execute: () => Effect.die(new Error("unused")),
     }),
@@ -285,13 +286,14 @@ it.effect("generates from fresh settled Session context without durable mutation
     expect(requests[0]?.system.map((part) => part.text)).toContain("Initial context")
     expect(requests[0]?.http?.headers).toMatchObject({ "X-Session-Id": sessionID })
     expect(requests[0]?.providerOptions).toMatchObject({ openai: { promptCacheKey: sessionID } })
-    expect(
-      requests[0]?.messages.flatMap((message) =>
-        message.role === "system"
-          ? message.content.flatMap((content) => (content.type === "text" ? [content.text] : []))
-          : [],
-      ),
-    ).toEqual(["Changed context"])
+    const instructionUpdates = requests[0]?.messages.flatMap((message) =>
+      message.role === "system"
+        ? message.content.flatMap((content) => (content.type === "text" ? [content.text] : []))
+        : [],
+    )
+    expect(instructionUpdates).toHaveLength(1)
+    expect(instructionUpdates?.[0]).toContain("Changed context")
+    expect(instructionUpdates?.[0]).toContain("Captured Code Mode catalog")
     expect(userTexts(requests[0])).toEqual(["Existing durable context", "Summarize privately"])
     expect(
       requests[0]?.messages.flatMap((message) =>
diff --git a/packages/core/test/session-runner-tool-registry.test.ts b/packages/core/test/session-runner-tool-registry.test.ts
index 3109509581a..7ba1322002d 100644
--- a/packages/core/test/session-runner-tool-registry.test.ts
+++ b/packages/core/test/session-runner-tool-registry.test.ts
@@ -533,6 +533,7 @@ describe("ToolRegistry", () => {
         .pipe(Scope.provide(scope))
       const toolSet = yield* service.snapshot()
       const execute = toolSet.definitions.find((tool) => tool.name === "execute")
+      expect(toolSet.codeModeInstructions).toContain("tools.echo")
       expect(execute?.description).toContain("confined Code Mode runtime")
       expect(execute?.description).not.toContain("Echo text")
       yield* Scope.close(scope, Exit.void)
diff --git a/packages/core/test/session-runner.test.ts b/packages/core/test/session-runner.test.ts
index 04f5ba0d5f7..a96e08eb545 100644
--- a/packages/core/test/session-runner.test.ts
+++ b/packages/core/test/session-runner.test.ts
@@ -43,6 +43,7 @@ import * as SessionRunnerLLM from "@opencode-ai/core/session/runner/llm"
 import { SessionRunnerModel } from "@opencode-ai/core/session/runner/model"
 import { SessionUsage } from "@opencode-ai/core/session/usage"
 import { ToolRegistry } from "@opencode-ai/core/tool/registry"
+import { CodeMode } from "@opencode-ai/core/codemode"
 import { PluginSupervisor } from "@opencode-ai/core/plugin/supervisor"
 import { PluginHooks } from "@opencode-ai/core/plugin/hooks"
 import { SystemPromptPlugin } from "@opencode-ai/core/plugin/system-prompt"
@@ -368,6 +369,12 @@ const pluginSupervisor = Layer.succeed(
     flush: Effect.suspend(() => pluginFlushHook),
   }),
 )
+let codeModeMaterializations: ReadonlyArray<CodeMode.Materialization> = []
+let codeModeMaterializationCount = 0
+const codeMode = Layer.mock(CodeMode.Service, {
+  register: () => Effect.void,
+  materialize: () => Effect.sync(() => codeModeMaterializations[codeModeMaterializationCount++] ?? {}),
+})
 const promptCatalog = Layer.mock(Catalog.Service, {
   provider: {
     get: () => Effect.succeed(undefined),
@@ -405,6 +412,7 @@ const runnerLayer = AppNodeBuilder.build(SessionRunnerLLM.node, [
   [McpInstructions.node, mcpInstructions],
   [ToolOutputStore.node, toolOutputStore],
   [PluginSupervisor.node, pluginSupervisor],
+  [CodeMode.node, codeMode],
 ])
 const execution = Layer.effect(
   SessionExecution.Service,
@@ -464,6 +472,7 @@ const it = testEffect(
       [Config.node, config],
       [ToolOutputStore.node, toolOutputStore],
       [PluginSupervisor.node, pluginSupervisor],
+      [CodeMode.node, codeMode],
     ],
   ),
 )
@@ -512,6 +521,8 @@ const setup = Effect.gen(function* () {
   systemLoadHook = Effect.void
   modelResolveHook = Effect.void
   pluginFlushHook = Effect.void
+  codeModeMaterializations = []
+  codeModeMaterializationCount = 0
   currentModel = model
   skillBaselines.clear()
   responses = undefined
@@ -823,6 +834,45 @@ const verifyPartialFlushOnInterruption = (kind: FragmentKind) =>
   })
 
 describe("SessionRunnerLLM", () => {
+  it.effect("uses one Code Mode materialization per request for instructions and execution", () =>
+    Effect.gen(function* () {
+      const executed: string[] = []
+      const execute = (name: string) =>
+        Tool.make({
+          description: `Execute ${name}`,
+          input: Schema.Struct({}),
+          output: Schema.String,
+          execute: () => Effect.sync(() => executed.push(name)).pipe(Effect.as({ output: name })),
+        })
+      const session = yield* setup
+      codeModeMaterializations = [
+        { instructions: "Code Mode catalog A", tool: execute("A") },
+        { instructions: "Code Mode catalog B", tool: execute("B") },
+        { instructions: "Code Mode catalog C", tool: execute("C") },
+        { instructions: "Code Mode catalog D", tool: execute("D") },
+      ]
+      yield* admit(session, "Use Code Mode")
+      responses = [reply.tool("call-execute", "execute", {}), reply.stop()]
+
+      yield* session.resume(sessionID)
+
+      expect(requests).toHaveLength(2)
+      expect(codeModeMaterializationCount).toBe(2)
+      expect(requests[0]?.system.some((part) => part.text.includes("Code Mode catalog A"))).toBe(true)
+      expect(requests[0]?.system.some((part) => part.text.includes("Code Mode catalog B"))).toBe(false)
+      expect(requests[0]?.tools.find((tool) => tool.name === "execute")?.description).toBe("Execute A")
+      expect(executed).toEqual(["A"])
+      expect(requests[1]?.tools.find((tool) => tool.name === "execute")?.description).toBe("Execute B")
+      expect(
+        requests[1]?.messages.some(
+          (message) =>
+            message.role === "system" &&
+            message.content.some((part) => part.type === "text" && part.text.includes("Code Mode catalog B")),
+        ),
+      ).toBe(true)
+    }),
+  )
+
   it.effect("applies session context hooks without exposing unavailable tools", () =>
     Effect.gen(function* () {
       const session = yield* setup