Fix cross-session MCP resume routing

Author: RhysSullivan

apps/cloud/src/mcp/agent-handler.ts

@@ -13,6 +13,7 @@ import {
   withVerifiedIdentityHeaders,
 } from "@executor-js/cloudflare/mcp/do-headers";
 import type { McpSessionProps } from "@executor-js/cloudflare/mcp/agent-durable-object";
+import { mcpSessionDurableObjectName } from "@executor-js/cloudflare/mcp/execution-owner-directory";
 
 import { wrapMcpSseResponse } from "../observability/memory-metrics";
 import { cloudMcpAuth } from "./auth-provider";
@@ -70,7 +71,7 @@ const renderAuthError = (
 const sessionStub = (env: Env, sessionId: string): McpAgentSessionStub =>
   // oxlint-disable-next-line executor/no-double-cast -- boundary: Workers types expose only DurableObjectStub, but RPC methods are generated from the bound DO class.
   env.MCP_SESSION.get(
-    env.MCP_SESSION.idFromName(`streamable-http:${sessionId}`),
+    env.MCP_SESSION.idFromName(mcpSessionDurableObjectName(sessionId)),
   ) as unknown as McpAgentSessionStub;
 
 const authenticate = (request: Request) =>

apps/cloud/src/mcp/session-durable-object.ts

@@ -36,6 +36,7 @@ import {
   type SessionMeta,
 } from "@executor-js/cloudflare/mcp/agent-durable-object";
 import {
+  mcpSessionDurableObjectName,
   mcpExecutionOwnerDirectoryFromNamespace,
   type McpExecutionOwnerDirectory,
   type McpExecutionOwnerRoute,
@@ -212,7 +213,7 @@ export class McpSessionDOSqlite extends McpAgentSessionDOBase<Env, CloudSessionD
       try: () =>
         (
           env.MCP_SESSION.get(
-            env.MCP_SESSION.idFromString(owner.sessionId),
+            env.MCP_SESSION.idFromName(mcpSessionDurableObjectName(owner.sessionId)),
           ) as unknown as McpModelResumeStub
         ).resumeExecutionForModel(executionId, identity, response),
       catch: (cause) => new McpModelResumeForwardError({ cause }),

apps/host-cloudflare/src/mcp/agent-handler.ts

@@ -13,6 +13,7 @@ import {
   withVerifiedIdentityHeaders,
 } from "@executor-js/cloudflare/mcp/do-headers";
 import type { McpSessionProps } from "@executor-js/cloudflare/mcp/agent-durable-object";
+import { mcpSessionDurableObjectName } from "@executor-js/cloudflare/mcp/execution-owner-directory";
 
 import type { CloudflareConfig, CloudflareEnv } from "../config";
 import { cloudflareAccessMcpAuth } from "./auth";
@@ -70,7 +71,7 @@ const renderAuthError = (
 const sessionStub = (env: CloudflareEnv, sessionId: string): McpAgentSessionStub =>
   // oxlint-disable-next-line executor/no-double-cast -- boundary: Workers types expose only DurableObjectStub, but RPC methods are generated from the bound DO class.
   env.MCP_SESSION.get(
-    env.MCP_SESSION.idFromName(`streamable-http:${sessionId}`),
+    env.MCP_SESSION.idFromName(mcpSessionDurableObjectName(sessionId)),
   ) as unknown as McpAgentSessionStub;
 
 const authenticate = (request: Request, config: CloudflareConfig) =>

apps/host-cloudflare/src/mcp/index.ts

@@ -6,6 +6,7 @@ import type {
   McpSessionApprovalResult,
   McpSessionResumeApprovalResult,
 } from "@executor-js/cloudflare/mcp/agent-durable-object";
+import { mcpSessionDurableObjectName } from "@executor-js/cloudflare/mcp/execution-owner-directory";
 import type { ResumeResponse } from "@executor-js/execution";
 
 import type { CloudflareConfig, CloudflareEnv } from "../config";
@@ -41,7 +42,9 @@ export const makeCloudflareApprovalHandler = (
 ): ((request: Request) => Promise<Response>) => {
   const { verify } = makeAccessVerifier(config);
   const stubFor = (sessionId: string): McpApprovalStub =>
-    toApprovalStub(env.MCP_SESSION.get(env.MCP_SESSION.idFromName(`streamable-http:${sessionId}`)));
+    toApprovalStub(
+      env.MCP_SESSION.get(env.MCP_SESSION.idFromName(mcpSessionDurableObjectName(sessionId))),
+    );
 
   return async (request) => {
     const principal = await Effect.runPromise(verify(request));

apps/host-cloudflare/src/mcp/session-durable-object.ts

@@ -15,6 +15,7 @@ import {
   type SessionMeta,
 } from "@executor-js/cloudflare/mcp/agent-durable-object";
 import {
+  mcpSessionDurableObjectName,
   mcpExecutionOwnerDirectoryFromNamespace,
   type McpExecutionOwnerDirectory,
   type McpExecutionOwnerRoute,
@@ -85,7 +86,7 @@ export class McpSessionDO extends McpAgentSessionDOBase<CloudflareEnv, CfSession
       try: () =>
         (
           this.cfEnv.MCP_SESSION.get(
-            this.cfEnv.MCP_SESSION.idFromName(`streamable-http:${owner.sessionId}`),
+            this.cfEnv.MCP_SESSION.idFromName(mcpSessionDurableObjectName(owner.sessionId)),
           ) as unknown as McpModelResumeStub
         ).resumeExecutionForModel(executionId, identity, response),
       catch: (cause) => new McpModelResumeForwardError({ cause }),

packages/core/execution/src/engine.ts

@@ -196,7 +196,7 @@ export const formatPausedExecution = (
   };
 };
 
-const formatTtlDuration = (ttlMs: number): string => {
+export const formatTtlDuration = (ttlMs: number): string => {
   const seconds = Math.max(1, Math.round(ttlMs / 1000));
   if (seconds % 60 === 0) {
     const minutes = seconds / 60;

packages/core/execution/src/index.ts

@@ -2,6 +2,7 @@ export {
   createExecutionEngine,
   formatExecuteResult,
   formatPausedExecution,
+  formatTtlDuration,
   type ExecutionEngine,
   type ExecutionEngineConfig,
   type ExecutionResult,

packages/hosts/cloudflare/src/mcp/agent-session-durable-object.ts

@@ -120,6 +120,7 @@ const MCP_HTTP_METHOD_HEADER = "cf-mcp-method";
 const MCP_MESSAGE_HEADER = "cf-mcp-message";
 const ACTIVE_POST_RESPONSE_WAIT_POLL_MS = 25;
 const ACTIVE_POST_RESPONSE_WAIT_MAX_MS = PAUSED_APPROVAL_TIMEOUT_MS + 30_000;
+const MODEL_RESUME_FORWARD_TIMEOUT_MS = 10_000;
 const approvalResponseKey = (executionId: string) => `approval-response:${executionId}`;
 
 type JsonRpcRequestId = string | number;
@@ -889,6 +890,11 @@ export abstract class McpAgentSessionDOBase<
       const forwarded = yield* self
         .forwardModelResumeToOwner(record.owner, identity, executionId, response)
         .pipe(
+          Effect.timeoutOrElse({
+            duration: `${MODEL_RESUME_FORWARD_TIMEOUT_MS} millis`,
+            orElse: () =>
+              Effect.succeed({ status: "execution_expired" as const, ttlMs: record.ttlMs }),
+          }),
           Effect.catchCause(() =>
             Effect.succeed({ status: "execution_expired" as const, ttlMs: record.ttlMs }),
           ),