import { Effect, type Cause } from "effect";import {  createMcpHandler,  isLegacyRequest,  McpServer,  WebStandardStreamableHTTPServerTransport,  type McpHttpHandler,} from "@modelcontextprotocol/server";import { serveStdio } from "@modelcontextprotocol/server/stdio"; import {  defaultMcpResource,  jsonRpcErrorBody,  mcpModernDisabledResponse,  mcpResourceKey,  type McpResource,} from "@executor-js/host-mcp";import {  appsEnabledForClientCapabilities,  buildMcpServer,  clientCapabilitiesFromRequest,  mcpRequestStateBindingFromBody,  requestBodyFromRequest,  type ExecutorMcpToolConfig,} from "@executor-js/host-mcp/tool-server";import {  approvalUrlForRequest,  decodeResumeResponse,  formatResumeAcknowledgement,  readArtifactsEnabled,  readElicitationMode,} from "@executor-js/host-mcp/browser-approval";import { makeInProcessBrowserApprovalStore } from "@executor-js/host-mcp/browser-approval-store";import {  formatPausedExecution,  type ExecutionEngine,  type ResumeResponse,} from "@executor-js/execution"; import { startIntegrationsRefresh } from "./integrations"; type AnyExecutionEngine = ExecutionEngine<Cause.YieldableError>; // ---------------------------------------------------------------------------// Streamable HTTP handler// --------------------------------------------------------------------------- export type McpRequestHandler = {  readonly handleRequest: (request: Request) => Promise<Response>;  /** GET `/api/mcp-sessions/:id/executions/:id` — paused detail for the console. */  readonly handlePausedRequest: (request: Request) => Promise<Response>;  /** POST `/api/mcp-sessions/:id/executions/:id/resume` — record the decision. */  readonly handleApprovalRequest: (request: Request) => Promise<Response>;  readonly close: () => Promise<void>;}; export interface LocalMcpServerConfig {  readonly config: ExecutorMcpToolConfig;  readonly close?: () => Promise<void>;} export interface LocalMcpRequestHandlerConfig {  readonly defaultConfig: ExecutorMcpToolConfig;  /** Emergency rollback for inbound MCP 2026-07-28 traffic only. */  readonly modernEnabled?: boolean;  readonly createConfigForResource?: (    resource: McpResource,  ) => Promise<LocalMcpServerConfig> | LocalMcpServerConfig;} // Local serves these error bodies in-process; like the self-host store they are// INNER responses (no CORS) — byte-identical to the prior hand-rolled copy// (`content-type: application/json` only) via the canonical renderer.const jsonError = (status: number, code: number, message: string): Response =>  jsonRpcErrorBody(status, code, message, { cors: false }); const formatBoundaryError = (error: unknown): unknown => {  // oxlint-disable-next-line executor/no-instanceof-error, executor/no-unknown-error-message -- boundary: MCP request handler catches unknown SDK/runtime failures for process logging  if (error instanceof Error) return error.stack ?? error.message;  return error;}; const ignoreClose = (close: (() => Promise<void>) | undefined): Promise<void> =>  close    ? Effect.runPromise(        Effect.ignore(          Effect.tryPromise({            try: close,            catch: () => undefined,          }),        ),      )    : Promise.resolve(); const pausedRequestPattern = /^\/api\/mcp-sessions\/([^/?#]+)\/executions\/([^/?#]+)$/;const approvalRequestPattern = /^\/api\/mcp-sessions\/([^/?#]+)\/executions\/([^/?#]+)\/resume$/; const json = (value: unknown, status = 200): Response =>  new Response(JSON.stringify(value), {    status,    headers: { "content-type": "application/json" },  }); const readResumeResponse = (request: Request): Promise<ResumeResponse | null> =>  Effect.runPromise(    Effect.tryPromise({      try: () => request.json(),      catch: () => null,    }).pipe(Effect.map((raw) => (raw === null ? null : decodeResumeResponse(raw)))),  ); const resumeApprovalResult = (executionId: string, response: ResumeResponse) => ({  status: "completed",  ...formatResumeAcknowledgement(executionId, response),  isError: false,}); const toolkitPathPattern = /^\/mcp\/toolkits\/([^/?#]+)\/?$/; const resourceFromRequest = (request: Request): McpResource | null => {  const pathname = new URL(request.url).pathname;  if (pathname === "/mcp" || pathname === "/mcp/") return defaultMcpResource;  const match = toolkitPathPattern.exec(pathname);  if (!match) return null;  return { kind: "toolkit", slug: decodeURIComponent(match[1]) };}; const engineFromConfig = (config: ExecutorMcpToolConfig): AnyExecutionEngine | null =>  "engine" in config ? config.engine : null; const normalizeHandlerConfig = (  input: ExecutorMcpToolConfig | LocalMcpRequestHandlerConfig,): LocalMcpRequestHandlerConfig => ("defaultConfig" in input ? input : { defaultConfig: input }); export const createMcpRequestHandler = (  input: ExecutorMcpToolConfig | LocalMcpRequestHandlerConfig,): McpRequestHandler => {  const handlerConfig = normalizeHandlerConfig(input);  const transports = new Map<string, WebStandardStreamableHTTPServerTransport>();  const servers = new Map<string, McpServer>();  const resources = new Map<string, McpResource>();  const sessionEngines = new Map<string, AnyExecutionEngine>();  const sessionClosers = new Map<string, () => Promise<void>>();  const modernHandlers = new Map<string, McpHttpHandler>();  const modernRequestBodies = new WeakMap<Request, unknown>();  const approvals = makeInProcessBrowserApprovalStore();  const defaultEngine = engineFromConfig(handlerConfig.defaultConfig);  let requestStateSigningKey: Uint8Array | undefined;   const signingKey = (): Uint8Array =>    (requestStateSigningKey ??= crypto.getRandomValues(new Uint8Array(32)));   const pausedDetail = (    sessionId: string,    executionId: string,  ): Promise<ReturnType<typeof formatPausedExecution> | null> =>    (sessionEngines.get(sessionId) ?? defaultEngine)      ? Effect.runPromise(          (sessionEngines.get(sessionId) ?? defaultEngine)!.getPausedExecution(executionId).pipe(            Effect.map((paused) => (paused ? formatPausedExecution(paused) : null)),            Effect.orElseSucceed(() => null),          ),        )      : Promise.resolve(null);   const configForResource = async (resource: McpResource): Promise<LocalMcpServerConfig> => {    if (!handlerConfig.createConfigForResource) return { config: handlerConfig.defaultConfig };    return handlerConfig.createConfigForResource(resource);  };   const dispose = async (id: string, opts: { transport?: boolean; server?: boolean } = {}) => {    const t = transports.get(id);    const s = servers.get(id);    const close = sessionClosers.get(id);    transports.delete(id);    servers.delete(id);    resources.delete(id);    sessionEngines.delete(id);    sessionClosers.delete(id);    if (opts.transport) await ignoreClose(t ? () => t.close() : undefined);    if (opts.server) await ignoreClose(s ? () => s.close() : undefined);    await ignoreClose(close);  };   const modernHandlerFor = (resource: McpResource): McpHttpHandler => {    const key = mcpResourceKey(resource);    const cached = modernHandlers.get(key);    if (cached) return cached;     const handler = createMcpHandler(      (context) => {        const request = context.requestInfo;        if (!request) {          // oxlint-disable-next-line executor/no-effect-escape-hatch -- boundary: the third-party McpServerFactory Promise contract has no typed failure channel; missing documented request context is an SDK defect          return Effect.runPromise(Effect.die("Modern MCP request context has no request"));        }        const parsedBody = modernRequestBodies.get(request);        return Effect.runPromise(          Effect.gen(function* () {            const resourceConfig = yield* Effect.promise(() => configForResource(resource));            const clientCapabilities = yield* clientCapabilitiesFromRequest(request);            const requestStateBinding = yield* Effect.promise(() =>              mcpRequestStateBindingFromBody({                body: parsedBody,                principal: "local",                resource,              }),            );            const server = yield* buildMcpServer({              ...resourceConfig.config,              artifactsEnabled: readArtifactsEnabled(request),              appsEnabled: appsEnabledForClientCapabilities(clientCapabilities),              requestStateSigningKey: signingKey(),              requestStatePrincipal: "local",              ...(requestStateBinding === null ? {} : { requestStateBinding }),            });            if (resourceConfig.close) {              const closeServer = server.close.bind(server);              const closeConfig = resourceConfig.close;              let closed = false;              server.close = async () => {                if (closed) return;                closed = true;                await ignoreClose(closeServer);                await ignoreClose(closeConfig);              };            }            return server;          }),        );      },      { legacy: "reject" },    );    modernHandlers.set(key, handler);    return handler;  };   return {    handleRequest: async (request) => {      const resource = resourceFromRequest(request);      if (!resource) return jsonError(404, -32001, "MCP resource not found");      if (!(await isLegacyRequest(request))) {        if (handlerConfig.modernEnabled === false) {          return mcpModernDisabledResponse({ cors: false });        }        const parsedBody = await Effect.runPromise(requestBodyFromRequest(request));        modernRequestBodies.set(request, parsedBody);        return modernHandlerFor(resource).fetch(request, { parsedBody });      }      const sessionId = request.headers.get("mcp-session-id");       if (sessionId) {        const transport = transports.get(sessionId);        if (!transport) return jsonError(404, -32001, "Session not found");        const sessionResource = resources.get(sessionId);        if (!sessionResource || mcpResourceKey(sessionResource) !== mcpResourceKey(resource)) {          return jsonError(403, -32003, "Session belongs to a different MCP resource");        }        return transport.handleRequest(request);      }       let created: McpServer | undefined;      let createdSessionId: string | null = null;      let resourceConfig: LocalMcpServerConfig | null = null;      const transport = new WebStandardStreamableHTTPServerTransport({        // SSE streaming (the spec default), NOT `enableJsonResponse: true`.        // JSON mode holds the POST open as a bare Promise and resolves it with        // one buffered body once every response is ready, so the transport has        // no open stream to write on: a server-to-client `elicitation/create`        // issued DURING a `tools/call` is dropped, and native elicitation dies        // on the client's request timeout (#1555). Streaming keeps the tool        // call's own stream writable in both directions, which is what native        // elicitation rides. Clients must already accept `text/event-stream`        // (the transport rejects a POST otherwise), so this costs nothing.        sessionIdGenerator: () => crypto.randomUUID(),        onsessioninitialized: (sid) => {          createdSessionId = sid;          transports.set(sid, transport);          if (created) servers.set(sid, created);          resources.set(sid, resource);          const engine = resourceConfig ? engineFromConfig(resourceConfig.config) : null;          if (engine) sessionEngines.set(sid, engine);          if (resourceConfig?.close) sessionClosers.set(sid, resourceConfig.close);        },        onsessionclosed: (sid) => void dispose(sid, { server: true }),      });       transport.onclose = () => {        const sid = transport.sessionId;        if (sid) void dispose(sid, { server: true });      };       // oxlint-disable-next-line executor/no-try-catch-or-throw -- boundary: MCP SDK handler must return JSON-RPC errors from thrown Promise APIs      try {        const elicitationMode = readElicitationMode(request);        resourceConfig = await configForResource(resource);        created = await Effect.runPromise(          buildMcpServer({            ...resourceConfig.config,            browserApprovalStore: approvals.store,            artifactsEnabled: readArtifactsEnabled(request),            appsEnabled: resourceConfig.config.restoredAppsEnabled ?? false,            requestStateSigningKey: signingKey(),            requestStatePrincipal: "local",            sessionful: true,            elicitationMode:              elicitationMode === "browser"                ? {                    mode: "browser" as const,                    approvalUrl: (executionId) =>                      approvalUrlForRequest(request, executionId, createdSessionId),                  }                : { mode: elicitationMode },          }),        );        await created.connect(transport);        const response = await transport.handleRequest(request);         if (!transport.sessionId) {          await ignoreClose(() => transport.close());          const server = created;          await ignoreClose(server ? () => server.close() : undefined);          await ignoreClose(resourceConfig?.close);        }        return response;      } catch (error) {        console.error("[mcp] handleRequest error:", formatBoundaryError(error));        if (!transport.sessionId) {          await ignoreClose(() => transport.close());          const server = created;          await ignoreClose(server ? () => server.close() : undefined);          await ignoreClose(resourceConfig?.close);        }        return jsonError(500, -32603, "Internal server error");      }    },     handlePausedRequest: async (request) => {      const match = pausedRequestPattern.exec(new URL(request.url).pathname);      if (!match) return json({ error: "Not found" }, 404);      if (request.method !== "GET") return json({ error: "Method not allowed" }, 405);       const paused = await pausedDetail(decodeURIComponent(match[1]), decodeURIComponent(match[2]));      if (!paused) return json({ error: "Paused execution not found" }, 404);      return json({ text: paused.text, structured: paused.structured });    },     handleApprovalRequest: async (request) => {      const match = approvalRequestPattern.exec(new URL(request.url).pathname);      if (!match) return json({ error: "Not found" }, 404);      if (request.method !== "POST") return json({ error: "Method not allowed" }, 405);       const sessionId = decodeURIComponent(match[1]);      const executionId = decodeURIComponent(match[2]);      // The shared engine must still hold the paused execution — guards stale ids.      if (!(await pausedDetail(sessionId, executionId))) {        return json({ error: "MCP session not found" }, 404);      }       const response = await readResumeResponse(request);      if (!response) return json({ error: "Invalid approval response" }, 400);       await Effect.runPromise(approvals.recordResponse(executionId, response));      return json(resumeApprovalResult(executionId, response));    },     close: async () => {      const ids = new Set([...transports.keys(), ...servers.keys()]);      await Promise.all([        ...[...ids].map((id) => dispose(id, { transport: true, server: true })),        ...[...modernHandlers.values()].map((handler) => handler.close()),      ]);    },  };}; // ---------------------------------------------------------------------------// Stdio transport// --------------------------------------------------------------------------- export const runMcpStdioServer = async (config: ExecutorMcpToolConfig): Promise<void> => {  startIntegrationsRefresh();   const requestStateSigningKey = crypto.getRandomValues(new Uint8Array(32));  const stdio = serveStdio(() =>    Effect.runPromise(      buildMcpServer({        ...config,        appsEnabled: config.restoredAppsEnabled ?? false,        requestStateSigningKey,        requestStatePrincipal: "local",        sessionful: true,      }),    ),  );   const waitForExit = () =>    new Promise<void>((resolve) => {      const finish = () => {        process.off("SIGINT", finish);        process.off("SIGTERM", finish);        process.stdin.off("end", finish);        process.stdin.off("close", finish);        resolve();      };      process.once("SIGINT", finish);      process.once("SIGTERM", finish);      process.stdin.once("end", finish);      process.stdin.once("close", finish);    });   // oxlint-disable-next-line executor/no-try-catch-or-throw -- boundary: stdio server lifetime uses Promise-based SDK/process APIs and always closes resources  try {    await waitForExit();  } finally {    await ignoreClose(() => stdio.close());  }};