Add RequestOptions.timeout

Author: jspahrsummers

src/shared/protocol.ts

@@ -37,6 +37,11 @@ export type ProtocolOptions = {
  enforceStrictCapabilities?: boolean;
 };
 
+/**
+ * The default request timeout, in miliseconds.
+ */
+export const DEFAULT_REQUEST_TIMEOUT_MSEC = 60000;
+
 /**
  * Options that can be given per request.
  */
@@ -50,6 +55,13 @@ export type RequestOptions = {
  * Can be used to cancel an in-flight request. This will cause an AbortError to be raised from request().
  */
  signal?: AbortSignal;
+
+ /**
+ * A timeout (in milliseconds) for this request. If exceeded, an McpError with code `RequestTimeout` will be raised from request().
+ *
+ * If not specified, `DEFAULT_REQUEST_TIMEOUT_MSEC` will be used as the timeout.
+ */
+ timeout?: number;
 };
 
 /**
@@ -379,7 +391,13 @@ export abstract class Protocol<
  };
  }
 
+ let timeoutId: ReturnType<typeof setTimeout> | undefined = undefined;
+
  this._responseHandlers.set(messageId, (response) => {
+ if (timeoutId !== undefined) {
+ clearTimeout(timeoutId);
+ }
+
  if (options?.signal?.aborted) {
  return;
  }
@@ -396,8 +414,7 @@ export abstract class Protocol<
  }
  });
 
- options?.signal?.addEventListener("abort", () => {
- const reason = options?.signal?.reason;
+ const cancel = (reason: unknown) => {
  this._responseHandlers.delete(messageId);
  this._progressHandlers.delete(messageId);
 
@@ -411,9 +428,34 @@ export abstract class Protocol<
  });
 
  reject(reason);
+ };
+
+ options?.signal?.addEventListener("abort", () => {
+ if (timeoutId !== undefined) {
+ clearTimeout(timeoutId);
+ }
+
+ cancel(options?.signal?.reason);
  });
 
- this._transport.send(jsonrpcRequest).catch(reject);
+ const timeout = options?.timeout ?? DEFAULT_REQUEST_TIMEOUT_MSEC;
+ timeoutId = setTimeout(
+ () =>
+ cancel(
+ new McpError(ErrorCode.RequestTimeout, "Request timed out", {
+ timeout,
+ }),
+ ),
+ timeout,
+ );
+
+ this._transport.send(jsonrpcRequest).catch((error) => {
+ if (timeoutId !== undefined) {
+ clearTimeout(timeoutId);
+ }
+
+ reject(error);
+ });
  });
  }
 

src/types.ts

@@ -105,6 +105,7 @@ export const JSONRPCResponseSchema = z
 export enum ErrorCode {
  // SDK error codes
  ConnectionClosed = -1,
+ RequestTimeout = -2,
 
  // Standard JSON-RPC error codes
  ParseError = -32700,