diff --git a/packages/core/src/codemode/instructions.ts b/packages/core/src/codemode/instructions.ts
index 66e5150dc5..3a546d79c2 100644
--- a/packages/core/src/codemode/instructions.ts
+++ b/packages/core/src/codemode/instructions.ts
@@ -8,6 +8,8 @@ import { CodeModeCatalog } from "./catalog"
 // prettier-ignore
 const prompt = (hasMoreTools: boolean) => `Run JavaScript to orchestrate tool calls and compose their results. Imports, direct filesystem access, and timers are unavailable. Do not use \`fetch\`; all external access goes through \`tools\`.
 
+Inside Code Mode, \`tools\` contains only the tools shown below${hasMoreTools ? " or returned by `search`" : ""}; surrounding top-level agent tools are not available and must not be called from the code.
+
 Prefer an explicit \`return\`; if omitted, the final top-level expression becomes the result. Await tool calls before returning; any calls still pending when execution ends are interrupted. Run independent calls concurrently with \`Promise.all\`.
 
 Do not infer or normalize tool names; use only the exact signatures shown below${hasMoreTools ? " or returned by `search`" : ""}, preserving bracket notation such as \`tools.<namespace>["tool-name"](input)\`.${hasMoreTools ? `
diff --git a/packages/core/test/codemode/catalog.test.ts b/packages/core/test/codemode/catalog.test.ts
index 176fe1c635..6831b46ad5 100644
--- a/packages/core/test/codemode/catalog.test.ts
+++ b/packages/core/test/codemode/catalog.test.ts
@@ -68,6 +68,9 @@ describe("CodeModeInstructions.render", () => {
     expect(instructions).not.toContain("## Search")
     expect(instructions).toContain("Do not infer or normalize tool names")
     expect(instructions).toContain('`tools.<namespace>["tool-name"](input)`')
+    expect(instructions).toContain(
+      "`tools` contains only the tools shown below; surrounding top-level agent tools are not available and must not be called from the code.",
+    )
   })
 
   test("describes the runtime and execution lifecycle concisely", () => {
@@ -88,6 +91,9 @@ describe("CodeModeInstructions.render", () => {
     expect(partial).toContain("- orders (1 tool, none shown)")
     expect(partial).toContain("## Search")
     expect(partial).toContain("Only some tool signatures are shown.")
+    expect(partial).toContain(
+      "`tools` contains only the tools shown below or returned by `search`; surrounding top-level agent tools are not available and must not be called from the code.",
+    )
     expect(partial).toContain("- search(input: {")
     expect(partial).toContain("  limit?: number,\n  offset?: number,")
     expect(partial).toContain("or returned by `search`")
@@ -169,7 +175,7 @@ describe("CodeModeInstructions.update", () => {
     expect(text).toContain("This catalog supersedes the previous Code Mode tool catalog.")
     expect(text).toContain("## Available tools")
     expect(text).not.toContain("## Search")
-    expect(text).not.toContain("must not be called")
+    expect(text).not.toContain("The following tools are no longer available")
   })
 
   test("renders namespace-only deltas without persisting hidden tool entries", () => {