diff --git a/packages/server/src/server/agent/providers/codex-mcp-agent.test.ts b/packages/server/src/server/agent/providers/codex-mcp-agent.test.ts
index 127da8a32..9b0a6de3f 100644
--- a/packages/server/src/server/agent/providers/codex-mcp-agent.test.ts
+++ b/packages/server/src/server/agent/providers/codex-mcp-agent.test.ts
@@ -402,7 +402,7 @@ function getConversationIdFromMetadata(metadata: unknown): string | undefined {
 
 describe("CodexMcpAgentClient (MCP integration)", () => {
   test(
-    "emits exactly one user_message and one assistant_message per turn",
+    "provider does not emit user_message (agent-manager handles that), emits exactly one assistant_message",
     async () => {
       const cwd = tmpCwd();
       const restoreSessionDir = useTempCodexSessionDir();
@@ -422,7 +422,8 @@ describe("CodexMcpAgentClient (MCP integration)", () => {
       try {
         session = await client.createSession(config);
 
-        // Simple prompt that should result in exactly one user message and one assistant message
+        // Simple prompt that should result in exactly one assistant message
+        // NOTE: user_message is NOT emitted by the provider - that's the agent-manager's job
         const prompt = "Say hello";
 
         for await (const event of session.stream(prompt)) {
@@ -440,10 +441,9 @@ describe("CodexMcpAgentClient (MCP integration)", () => {
           }
         }
 
-        // CRITICAL: There should be exactly ONE user_message event
-        expect(userMessages.length).toBe(1);
-        expect(userMessages[0].type).toBe("user_message");
-        expect(userMessages[0].text).toBe(prompt);
+        // Provider should NOT emit user_message - that's handled by agent-manager.recordUserMessage()
+        // This prevents duplicate user messages when running through the full stack.
+        expect(userMessages.length).toBe(0);
 
         // CRITICAL: There should be exactly ONE assistant_message event (not duplicated)
         expect(assistantMessages.length).toBe(1);
diff --git a/packages/server/src/server/agent/providers/codex-mcp-agent.ts b/packages/server/src/server/agent/providers/codex-mcp-agent.ts
index 2520e8d00..4d518aaba 100644
--- a/packages/server/src/server/agent/providers/codex-mcp-agent.ts
+++ b/packages/server/src/server/agent/providers/codex-mcp-agent.ts
@@ -2596,11 +2596,9 @@ class CodexMcpAgentSession implements AgentSession {
     this.currentAbortController = abortController;
 
     const promptText = toPromptText(prompt);
-    this.emitEvent({
-      type: "timeline",
-      provider: CODEX_PROVIDER,
-      item: { type: "user_message", text: promptText },
-    });
+    // NOTE: user_message is NOT emitted here because the agent-manager's
+    // recordUserMessage() already handles emitting the user message timeline
+    // event before calling stream(). Emitting here would cause duplicates.
 
     void this.forwardPrompt(promptText, options, abortController.signal).catch((error) => {
       const message = error instanceof Error ? error.message : String(error);