diff --git a/extensions/codex/src/app-server/thread-lifecycle.test.ts b/extensions/codex/src/app-server/thread-lifecycle.test.ts
index d3b7890c9a16..66a4f1748228 100644
--- a/extensions/codex/src/app-server/thread-lifecycle.test.ts
+++ b/extensions/codex/src/app-server/thread-lifecycle.test.ts
@@ -478,6 +478,26 @@ describe("Codex app-server native code mode config", () => {
         dynamicTools: [],
       },
     );
+    const withWrongNamespace = buildDeveloperInstructions(
+      createAttemptParams({ provider: "openai" }),
+      {
+        dynamicTools: [
+          {
+            type: "namespace",
+            name: "openclaw",
+            description: "",
+            tools: [
+              {
+                type: "function",
+                name: "sessions_yield",
+                description: "Different tool with the same leaf name",
+                inputSchema: { type: "object" },
+              },
+            ],
+          },
+        ],
+      },
+    );
 
     expect(withSessionsYield).toContain(
       "end the current turn with `openclaw_direct.sessions_yield`",
@@ -488,6 +508,8 @@ describe("Codex app-server native code mode config", () => {
     expect(withSessionsYield).toContain("Never loop-poll for native child completion.");
     expect(withoutSessionsYield).not.toContain("`openclaw_direct.sessions_yield`");
     expect(withoutSessionsYield).not.toContain("native `wait_agent`");
+    expect(withWrongNamespace).not.toContain("`openclaw_direct.sessions_yield`");
+    expect(withWrongNamespace).not.toContain("native `wait_agent`");
   });
 
   it("summarizes deferred dynamic tool names in developer instructions", () => {
diff --git a/extensions/codex/src/app-server/thread-prompt.ts b/extensions/codex/src/app-server/thread-prompt.ts
index faa6b19e6cf9..79d41063409d 100644
--- a/extensions/codex/src/app-server/thread-prompt.ts
+++ b/extensions/codex/src/app-server/thread-prompt.ts
@@ -4,7 +4,11 @@ import {
   type EmbeddedRunAttemptParams,
 } from "openclaw/plugin-sdk/agent-harness-runtime";
 import { listRegisteredPluginAgentPromptGuidance } from "openclaw/plugin-sdk/plugin-runtime";
-import { flattenCodexDynamicToolFunctions, type CodexDynamicToolSpec } from "./protocol.js";
+import {
+  CODEX_OPENCLAW_DIRECT_DYNAMIC_TOOL_NAMESPACE,
+  flattenCodexDynamicToolFunctions,
+  type CodexDynamicToolSpec,
+} from "./protocol.js";
 
 export function buildDeveloperInstructions(
   params: EmbeddedRunAttemptParams,
@@ -33,9 +37,14 @@ export function buildDeveloperInstructions(
 function buildNativeSubagentCompletionInstruction(
   dynamicTools: readonly CodexDynamicToolSpec[] | undefined,
 ): string | undefined {
-  const hasSessionsYield = flattenCodexDynamicToolFunctions(dynamicTools).some(
-    (tool) => tool.name.trim() === "sessions_yield",
+  const directNamespace = dynamicTools?.find(
+    (tool) =>
+      tool.type === "namespace" &&
+      tool.name.trim() === CODEX_OPENCLAW_DIRECT_DYNAMIC_TOOL_NAMESPACE,
   );
+  const hasSessionsYield =
+    directNamespace?.type === "namespace" &&
+    directNamespace.tools.some((tool) => tool.name.trim() === "sessions_yield");
   if (!hasSessionsYield) {
     return undefined;
   }