diff --git a/sdk/src/codex/connection.test.ts b/sdk/src/codex/connection.test.ts
index a1ba898..f0e5728 100644
--- a/sdk/src/codex/connection.test.ts
+++ b/sdk/src/codex/connection.test.ts
@@ -421,6 +421,121 @@ describe("CodexAxonConnection", () => {
     expect(handlerSignal?.aborted).toBe(true);
   });
 
+  it("tracks external resolution until the handler response finishes publishing", async () => {
+    const { ctrl, mock, conn } = setup();
+    let responseSignal: AbortSignal | undefined;
+    mock.axon.publish.mockImplementationOnce(
+      (...args: unknown[]) =>
+        new Promise<void>((_resolve, reject) => {
+          responseSignal = (args[1] as { signal?: AbortSignal } | undefined)?.signal;
+          responseSignal?.addEventListener("abort", () => reject(new Error("publish aborted")), {
+            once: true,
+          });
+        }),
+    );
+    conn.onApprovalRequest("mcpServer/elicitation/request", () => ({
+      action: "accept",
+      content: { city: "Paris" },
+      _meta: null,
+    }));
+    await conn.connect();
+    ctrl.push(
+      makeAgentEvent("mcpServer/elicitation/request", {
+        method: "mcpServer/elicitation/request",
+        id: "elicit-publishing",
+        params: { mode: "form", message: "Which city?", requestedSchema: {} },
+      }),
+    );
+    await tick();
+    expect(responseSignal).toBeDefined();
+
+    ctrl.push(
+      makeAgentEvent("serverRequest/resolved", {
+        method: "serverRequest/resolved",
+        params: { threadId: "thr-1", requestId: "elicit-publishing" },
+      }),
+    );
+    await tick();
+
+    expect(responseSignal?.aborted).toBe(true);
+    // Once Codex reports the request resolved, the in-flight response is
+    // canceled and its failure does not trigger a second, stale error response.
+    expect(mock.axon.publish).toHaveBeenCalledTimes(1);
+  });
+
+  it("cancels a fallback error response when app-server resolves the request", async () => {
+    const { ctrl, mock, conn } = setup();
+    let responseSignal: AbortSignal | undefined;
+    mock.axon.publish.mockImplementationOnce(
+      (...args: unknown[]) =>
+        new Promise<void>((_resolve, reject) => {
+          responseSignal = (args[1] as { signal?: AbortSignal } | undefined)?.signal;
+          responseSignal?.addEventListener("abort", () => reject(new Error("publish aborted")), {
+            once: true,
+          });
+        }),
+    );
+    conn.onApprovalRequest("mcpServer/elicitation/request", () => {
+      throw new Error("handler failed");
+    });
+    await conn.connect();
+    ctrl.push(
+      makeAgentEvent("mcpServer/elicitation/request", {
+        method: "mcpServer/elicitation/request",
+        id: "elicit-error-publishing",
+        params: { mode: "form", message: "Which city?", requestedSchema: {} },
+      }),
+    );
+    await tick();
+    expect(responseSignal).toBeDefined();
+
+    ctrl.push(
+      makeAgentEvent("serverRequest/resolved", {
+        method: "serverRequest/resolved",
+        params: { threadId: "thr-1", requestId: "elicit-error-publishing" },
+      }),
+    );
+    await tick();
+
+    expect(responseSignal?.aborted).toBe(true);
+    expect(mock.axon.publish).toHaveBeenCalledTimes(1);
+  });
+
+  it("tracks default responses until they finish publishing", async () => {
+    const { ctrl, mock, conn } = setup();
+    let responseSignal: AbortSignal | undefined;
+    mock.axon.publish.mockImplementationOnce(
+      (...args: unknown[]) =>
+        new Promise<void>((_resolve, reject) => {
+          responseSignal = (args[1] as { signal?: AbortSignal } | undefined)?.signal;
+          responseSignal?.addEventListener("abort", () => reject(new Error("publish aborted")), {
+            once: true,
+          });
+        }),
+    );
+    await conn.connect();
+    ctrl.push(
+      makeAgentEvent("item/commandExecution/requestApproval", {
+        method: "item/commandExecution/requestApproval",
+        id: "default-publishing",
+        params: {},
+      }),
+    );
+    await tick();
+    expect(responseSignal).toBeDefined();
+
+    ctrl.push(
+      makeAgentEvent("serverRequest/resolved", {
+        method: "serverRequest/resolved",
+        params: { threadId: "thr-1", requestId: "default-publishing" },
+      }),
+    );
+    await tick();
+
+    expect(responseSignal?.aborted).toBe(true);
+    expect(mock.axon.publish).toHaveBeenCalledTimes(1);
+  });
+
   it("replaces a stale parked handler when the same request is replayed", async () => {
     const { ctrl, mock, conn } = setup({ requestTimeoutMs: 1_000 });
     const signals: AbortSignal[] = [];
diff --git a/sdk/src/codex/connection.ts b/sdk/src/codex/connection.ts
index 944838e..4b6c825 100644
--- a/sdk/src/codex/connection.ts
+++ b/sdk/src/codex/connection.ts
@@ -73,6 +73,14 @@ export type ApprovalHandler = (
   context: ApprovalHandlerContext,
 ) => Promise<unknown> | unknown;
 const SERVER_REQUEST_RESOLVED = Symbol("server-request-resolved");
+interface ServerRequestLifecycle {
+  /** Cancels any handler or outbound response when app-server clears the request. */
+  signal: AbortSignal;
+  /** True when app-server cleared the request. */
+  resolvedElsewhere: () => boolean;
+  /** Stop tracking the request after its final response has finished publishing. */
+  release: () => void;
+}
 /**
  * JSON-RPC error returned by the Codex app-server for a client request.
  * Preserves the wire `code` and `data` alongside the message.
@@ -460,40 +468,71 @@ export class CodexAxonConnection {
         return { permissions: {}, scope: "turn" };
     }
   }
+  private trackServerRequest(requestId: string | number): ServerRequestLifecycle {
+    let resolvedElsewhere = false;
+    const controller = new AbortController();
+    const release = () => {
+      if (this.serverRequestResolutionWaiters.get(requestId) === onResolved) {
+        this.serverRequestResolutionWaiters.delete(requestId);
+      }
+    };
+    const onResolved = () => {
+      resolvedElsewhere = true;
+      release();
+      controller.abort();
+    };
+    this.serverRequestResolutionWaiters.get(requestId)?.();
+    this.serverRequestResolutionWaiters.set(requestId, onResolved);
+    return { signal: controller.signal, resolvedElsewhere: () => resolvedElsewhere, release };
+  }
   private approvalWithTimeout(
     request: ApprovalRequest,
     handler: ApprovalHandler,
     timeoutMs: number,
+    requestSignal: AbortSignal,
   ): Promise<unknown | typeof SERVER_REQUEST_RESOLVED> {
     return new Promise((resolve, reject) => {
       let settled = false;
       let timer: ReturnType<typeof setTimeout> | undefined;
       const handlerController = new AbortController();
-      const finish = (value: unknown | typeof SERVER_REQUEST_RESOLVED, error?: unknown) => {
+      const finish = (result: unknown) => {
         if (settled) return;
         settled = true;
         if (timer) clearTimeout(timer);
-        if (this.serverRequestResolutionWaiters.get(request.id) === onResolved) {
-          this.serverRequestResolutionWaiters.delete(request.id);
-        }
+        requestSignal.removeEventListener("abort", onResolved);
+        handlerController.abort();
+        resolve(result);
+      };
+      const fail = (error: unknown) => {
+        if (settled) return;
+        settled = true;
+        if (timer) clearTimeout(timer);
+        requestSignal.removeEventListener("abort", onResolved);
         handlerController.abort();
-        if (error !== undefined) reject(error);
-        else resolve(value);
+        reject(error);
       };
-      const onResolved = () => finish(SERVER_REQUEST_RESOLVED);
-      this.serverRequestResolutionWaiters.get(request.id)?.();
-      this.serverRequestResolutionWaiters.set(request.id, onResolved);
+      const onResolved = () => {
+        if (settled) return;
+        settled = true;
+        if (timer) clearTimeout(timer);
+        requestSignal.removeEventListener("abort", onResolved);
+        handlerController.abort();
+        resolve(SERVER_REQUEST_RESOLVED);
+      };
+      if (requestSignal.aborted) {
+        onResolved();
+        return;
+      }
+      requestSignal.addEventListener("abort", onResolved, { once: true });
       timer = setTimeout(() => finish(this.defaultDecline(request)), timeoutMs);
       Promise.resolve()
         .then(() => handler(request, { signal: handlerController.signal }))
-        .then(
-          (value) => finish(value),
-          (error) => finish(undefined, error),
-        );
+        .then(finish, fail);
     });
   }
   private async handleServerRequest(request: ServerRequest): Promise<void> {
     if (this.fatal || !this.transport?.isReady()) return;
+    let lifecycle: ServerRequestLifecycle | undefined;
     try {
       if (!CODEX_APPROVAL_REQUEST_METHOD_SET.has(request.method)) {
         await this.transport.write({
@@ -502,21 +541,37 @@ export class CodexAxonConnection {
         });
         return;
       }
+      lifecycle = this.trackServerRequest(request.id);
       const approval = request as ApprovalRequest;
       const handler = this.handlers.get(approval.method);
       const timeoutMs = this.options.requestTimeoutMs ?? 60_000;
-      const result = handler
-        ? await this.approvalWithTimeout(approval, handler, timeoutMs)
+      const outcome = handler
+        ? await this.approvalWithTimeout(approval, handler, timeoutMs, lifecycle.signal)
         : this.defaultApproval(approval);
-      if (result === SERVER_REQUEST_RESOLVED) return;
-      await this.transport?.write({ id: request.id, result });
+      if (outcome === SERVER_REQUEST_RESOLVED || lifecycle.resolvedElsewhere()) return;
+      await this.transport?.write(
+        { id: request.id, result: outcome },
+        { signal: lifecycle.signal },
+      );
     } catch (error) {
-      if (this.transport?.isReady()) {
-        await this.transport.write({
-          id: request.id,
-          error: { code: -32000, message: error instanceof Error ? error.message : String(error) },
-        });
+      if (!lifecycle?.resolvedElsewhere() && this.transport?.isReady()) {
+        try {
+          await this.transport.write(
+            {
+              id: request.id,
+              error: {
+                code: -32000,
+                message: error instanceof Error ? error.message : String(error),
+              },
+            },
+            lifecycle ? { signal: lifecycle.signal } : undefined,
+          );
+        } catch (publishError) {
+          if (!lifecycle?.resolvedElsewhere()) throw publishError;
+        }
       }
+    } finally {
+      lifecycle?.release();
     }
   }
   /**
diff --git a/sdk/src/codex/transport.ts b/sdk/src/codex/transport.ts
index 886384b..1a63687 100644
--- a/sdk/src/codex/transport.ts
+++ b/sdk/src/codex/transport.ts
@@ -22,7 +22,7 @@ export interface CodexAxonTransportOptions {
 export interface CodexTransport {
   connect(): Promise<void>;
   reconnect(): Promise<void>;
-  write(frame: CodexFrame | string): Promise<void>;
+  write(frame: CodexFrame | string, options?: { signal?: AbortSignal }): Promise<void>;
   readMessages(): AsyncIterable<CodexFrame>;
   close(): Promise<void>;
   abortStream(): void;
@@ -76,8 +76,8 @@ export class CodexAxonTransport implements CodexTransport {
   async reconnect(): Promise<void> {
     await this.inner.reconnect();
   }
-  async write(frame: CodexFrame | string): Promise<void> {
-    await this.inner.write(frame);
+  async write(frame: CodexFrame | string, options?: { signal?: AbortSignal }): Promise<void> {
+    await this.inner.write(frame, options);
   }
   async *readMessages(): AsyncGenerator<CodexFrame> {
     yield* this.inner.readMessages();
diff --git a/sdk/src/shared/axon-frame-transport.ts b/sdk/src/shared/axon-frame-transport.ts
index 487fea3..223a697 100644
--- a/sdk/src/shared/axon-frame-transport.ts
+++ b/sdk/src/shared/axon-frame-transport.ts
@@ -63,7 +63,7 @@ export class AxonFrameTransport<TFrame> {
     );
   }
 
-  async write(data: TFrame | string): Promise<void> {
+  async write(data: TFrame | string, options?: { signal?: AbortSignal }): Promise<void> {
     if (!this.isReady())
       throw new Error("Transport is not ready. Call connect() first or check isReady().");
     const raw = typeof data === "string" ? data : JSON.stringify(data);
@@ -71,13 +71,16 @@ export class AxonFrameTransport<TFrame> {
     if (frame === undefined && !this.options.allowInvalidOutbound)
       throw new Error("Cannot publish an invalid protocol frame");
     if (frame !== undefined) this.options.validateOutbound?.(frame);
-    await this.axon.publish({
-      event_type: this.options.resolveEventType(frame, raw),
-      origin: "USER_EVENT",
-      payload: raw,
-      source:
-        typeof this.options.source === "function" ? this.options.source() : this.options.source,
-    });
+    await this.axon.publish(
+      {
+        event_type: this.options.resolveEventType(frame, raw),
+        origin: "USER_EVENT",
+        payload: raw,
+        source:
+          typeof this.options.source === "function" ? this.options.source() : this.options.source,
+      },
+      options?.signal ? { signal: options.signal } : undefined,
+    );
   }
 
   async *readMessages(): AsyncGenerator<TFrame> {