From cd31d7637110702c1f2102c5a6913141e6c0c4bf Mon Sep 17 00:00:00 2001 From: cliffhall Date: Sun, 13 Sep 2026 21:13:30 -0400 Subject: [PATCH] fix: reset the relay's request-response waits on progress notifications (#2028) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The web client drives its MCP Client through a two-hop relay (RemoteClientTransport -> Node backend -> upstream transport). The relay added two request-response waits that the direct transports don't have — the backend's RemoteSession.waitForRequestResponse and the browser's RemoteClientTransport.waitForSseResponse — and both were hardcoded to 60s and blind to notifications/progress. The SDK Client's own request timeout resets on progress (resetTimeoutOnProgress, which the Inspector enables), but the relay's progress-blind waits fire first and shadow it, so a long-running tool that reports progress is cancelled at 60s on the web client alone while it completes over the CLI/TUI and other MCP clients. Reset both relay waits on a notifications/progress whose progressToken matches the pending request id, mirroring the SDK's resetTimeoutOnProgress. A shared browser-safe progressTokenOf helper extracts the token. Log messages (notifications/message, i.e. ctx.info) deliberately do not reset the deadline, matching the SDK and every other client. Co-Authored-By: Claude Opus 4.8 Claude-Session: https://claude.ai/code/session_01PsmUAZ6aLUAFqenjJKSSRp Signed-off-by: cliffhall --- .../core/mcp/remote/progressToken.test.ts | 73 ++++++++++++ .../mcp/remote/remoteClientTransport.test.ts | 111 ++++++++++++++++++ .../mcp/remote/remote-session.test.ts | 68 +++++++++++ core/mcp/remote/node/remote-session.ts | 74 +++++++++--- core/mcp/remote/progressToken.ts | 33 ++++++ core/mcp/remote/remoteClientTransport.ts | 46 ++++++-- 6 files changed, 380 insertions(+), 25 deletions(-) create mode 100644 clients/web/src/test/core/mcp/remote/progressToken.test.ts create mode 100644 core/mcp/remote/progressToken.ts diff --git a/clients/web/src/test/core/mcp/remote/progressToken.test.ts b/clients/web/src/test/core/mcp/remote/progressToken.test.ts new file mode 100644 index 00000000..668a3843 --- /dev/null +++ b/clients/web/src/test/core/mcp/remote/progressToken.test.ts @@ -0,0 +1,73 @@ +import { describe, it, expect } from "vitest"; +import { progressTokenOf } from "@inspector/core/mcp/remote/progressToken.js"; +import type { JSONRPCMessage } from "@modelcontextprotocol/client"; + +// Cast helper: these fixtures are deliberately off-spec to exercise the guard +// branches, which the typed JSONRPCMessage shape would otherwise forbid. +const msg = (m: unknown): JSONRPCMessage => m as JSONRPCMessage; + +describe("progressTokenOf (#2028)", () => { + it("returns a numeric progressToken from a progress notification", () => { + expect( + progressTokenOf({ + jsonrpc: "2.0", + method: "notifications/progress", + params: { progressToken: 42, progress: 1, total: 3 }, + }), + ).toBe(42); + }); + + it("returns a string progressToken", () => { + expect( + progressTokenOf({ + jsonrpc: "2.0", + method: "notifications/progress", + params: { progressToken: "abc", progress: 1 }, + }), + ).toBe("abc"); + }); + + it("returns undefined for a different notification method", () => { + expect( + progressTokenOf({ + jsonrpc: "2.0", + method: "notifications/message", + params: { level: "info", data: {} }, + }), + ).toBeUndefined(); + }); + + it("returns undefined for a JSON-RPC response (no method)", () => { + expect( + progressTokenOf({ jsonrpc: "2.0", id: 1, result: {} }), + ).toBeUndefined(); + }); + + it("returns undefined when a progress note carries no params", () => { + expect( + progressTokenOf( + msg({ jsonrpc: "2.0", method: "notifications/progress" }), + ), + ).toBeUndefined(); + }); + + it("returns undefined when params is null", () => { + expect( + progressTokenOf( + msg({ jsonrpc: "2.0", method: "notifications/progress", params: null }), + ), + ).toBeUndefined(); + }); + + it("returns undefined when the progressToken is neither string nor number", () => { + expect( + progressTokenOf( + msg({ + jsonrpc: "2.0", + method: "notifications/progress", + params: { progressToken: { nested: true } }, + }), + ), + ).toBeUndefined(); + }); +}); diff --git a/clients/web/src/test/core/mcp/remote/remoteClientTransport.test.ts b/clients/web/src/test/core/mcp/remote/remoteClientTransport.test.ts index 1aed2bea..1fc58e92 100644 --- a/clients/web/src/test/core/mcp/remote/remoteClientTransport.test.ts +++ b/clients/web/src/test/core/mcp/remote/remoteClientTransport.test.ts @@ -686,4 +686,115 @@ describe("RemoteClientTransport", () => { await transport.close(); }); }); + + describe("progress notifications keep the SSE response wait alive (#2028)", () => { + // A remote backend holds POST /api/mcp/send open until the JSON-RPC + // response, and the browser bounds that wait with `sseResponseTimeoutMs`. + // For a long tool that reports progress, that wait must re-arm on each + // `notifications/progress` — mirroring the SDK client's + // `resetTimeoutOnProgress` — or the web client alone times out a call that + // every other transport rides out. Log messages must NOT re-arm it. + function backendHoldingSend(): { + fetchFn: typeof fetch; + getSse: () => ReturnType; + getSentId: () => string | number | undefined; + } { + let sse!: ReturnType; + let sentId: string | number | undefined; + const fetchFn = vi + .fn() + .mockImplementation(async (input, init) => { + const url = String(input); + if (url.endsWith("/api/mcp/connect") && init?.method === "POST") { + return new Response(JSON.stringify({ sessionId: "s-progress" }), { + status: 200, + }); + } + if (url.includes("/api/mcp/events")) { + sse = createPushableSseStream(); + return sse.response; + } + if (url.endsWith("/api/mcp/send") && init?.method === "POST") { + const body = JSON.parse(String(init.body)) as { + message: { id?: string | number }; + }; + sentId = body.message.id; + // Backend accepted the request; the response arrives later over SSE. + return new Response(JSON.stringify({ ok: true }), { status: 200 }); + } + return new Response("not found", { status: 404 }); + }) as unknown as typeof fetch; + return { fetchFn, getSse: () => sse, getSentId: () => sentId }; + } + + const delay = (ms: number) => new Promise((r) => setTimeout(r, ms)); + + it("re-arms the wait on each progress note, so a call outliving the timeout still resolves", async () => { + const { fetchFn, getSse, getSentId } = backendHoldingSend(); + const transport = new RemoteClientTransport( + { baseUrl, fetchFn, sseResponseTimeoutMs: 150 }, + config, + ); + await transport.start(); + + const sent = transport.send({ + jsonrpc: "2.0", + id: 1, + method: "tools/call", + }); + + // Emit progress every 100ms (< the 150ms window) for ~400ms total, then + // the response. Without the re-arm the wait dies at 150ms. + for (let i = 0; i < 4; i++) { + await delay(100); + getSse().pushMessage({ + jsonrpc: "2.0", + method: "notifications/progress", + params: { progressToken: getSentId(), progress: i, total: 4 }, + }); + } + getSse().pushMessage({ + jsonrpc: "2.0", + id: getSentId(), + result: { ok: true }, + }); + + await expect(sent).resolves.toBeUndefined(); + await transport.close(); + }); + + it("does not re-arm on notifications/message, so a log-only call still times out", async () => { + const { fetchFn, getSse, getSentId } = backendHoldingSend(); + const transport = new RemoteClientTransport( + { baseUrl, fetchFn, sseResponseTimeoutMs: 150 }, + config, + ); + await transport.start(); + + const sent = transport.send({ + jsonrpc: "2.0", + id: 1, + method: "tools/call", + }); + void sent.catch(() => {}); + + // Only log messages — these must not extend the deadline. + for (let i = 0; i < 4; i++) { + await delay(50); + getSse().pushMessage({ + jsonrpc: "2.0", + method: "notifications/message", + params: { + level: "info", + data: { msg: `tick ${i}`, token: getSentId() }, + }, + }); + } + + await expect(sent).rejects.toThrow( + /Timed out waiting for MCP response on SSE/, + ); + await transport.close(); + }); + }); }); diff --git a/clients/web/src/test/integration/mcp/remote/remote-session.test.ts b/clients/web/src/test/integration/mcp/remote/remote-session.test.ts index c152b960..285efebd 100644 --- a/clients/web/src/test/integration/mcp/remote/remote-session.test.ts +++ b/clients/web/src/test/integration/mcp/remote/remote-session.test.ts @@ -231,6 +231,74 @@ describe("RemoteSession", () => { await expect(wait).resolves.toBeUndefined(); }); + it("a matching progress notification re-arms the wait past its original deadline (#2028)", async () => { + vi.useFakeTimers(); + const session = new RemoteSession("s-progress-reset"); + const wait = session.waitForRequestResponse(5, 1000); + // Almost at the deadline, then a progress note for this request arrives. + await vi.advanceTimersByTimeAsync(900); + session.onMessage({ + jsonrpc: "2.0", + method: "notifications/progress", + params: { progressToken: 5, progress: 1, total: 10 }, + }); + // Past the *original* 1000ms deadline: without the re-arm this would have + // already rejected, and the resolve below would be a no-op on a dead wait. + await vi.advanceTimersByTimeAsync(900); + session.onMessage({ jsonrpc: "2.0", id: 5, result: {} }); + await expect(wait).resolves.toBeUndefined(); + vi.useRealTimers(); + }); + + it("a notifications/message does NOT re-arm the wait (log messages don't extend the deadline, #2028)", async () => { + vi.useFakeTimers(); + const session = new RemoteSession("s-message-no-reset"); + const wait = session.waitForRequestResponse(6, 1000); + const rejection = expect(wait).rejects.toThrow(/timed out/); + await vi.advanceTimersByTimeAsync(500); + session.onMessage({ + jsonrpc: "2.0", + method: "notifications/message", + params: { level: "info", data: { msg: "tick" } }, + }); + await vi.advanceTimersByTimeAsync(500); + await rejection; + vi.useRealTimers(); + }); + + it("noteRequestProgress is a no-op for an id with no pending wait", () => { + const session = new RemoteSession("s-progress-noop"); + expect(() => session.noteRequestProgress(999)).not.toThrow(); + }); + + it("a progress notification on a timeoutMs=0 wait leaves it timerless and it still resolves", async () => { + const session = new RemoteSession("s-progress-notimer"); + const wait = session.waitForRequestResponse(7, 0); + session.onMessage({ + jsonrpc: "2.0", + method: "notifications/progress", + params: { progressToken: 7, progress: 1 }, + }); + session.onMessage({ jsonrpc: "2.0", id: 7, result: {} }); + await expect(wait).resolves.toBeUndefined(); + }); + + it("a progress notification with a non-token progressToken re-arms nothing", async () => { + vi.useFakeTimers(); + const session = new RemoteSession("s-progress-bad-token"); + const wait = session.waitForRequestResponse(8, 1000); + const rejection = expect(wait).rejects.toThrow(/timed out/); + // A malformed token (object) must be ignored, not coerced to a key. + session.onMessage({ + jsonrpc: "2.0", + method: "notifications/progress", + params: { progressToken: { bad: true }, progress: 1 }, + } as unknown as Parameters[0]); + await vi.advanceTimersByTimeAsync(1000); + await rejection; + vi.useRealTimers(); + }); + it("endSend is a no-op when no send is active", () => { const session = new RemoteSession("s-endsend-noop"); expect(session.hasActiveSend()).toBe(false); diff --git a/core/mcp/remote/node/remote-session.ts b/core/mcp/remote/node/remote-session.ts index fc7c7654..2ae68a7c 100644 --- a/core/mcp/remote/node/remote-session.ts +++ b/core/mcp/remote/node/remote-session.ts @@ -10,6 +10,7 @@ import type { AuthChallenge } from "../../../auth/challenge.js"; import { AuthChallengeError } from "../../../auth/challenge.js"; import type { RemoteAuthProviderHandle } from "./tokenAuthProvider.js"; import type { RemoteAuthState } from "../types.js"; +import { progressTokenOf } from "../progressToken.js"; export interface SessionEvent { type: RemoteEvent["type"]; @@ -19,6 +20,14 @@ export interface SessionEvent { type RequestWait = { resolve: () => void; reject: (error: Error) => void; + /** + * Re-arm this wait's timeout for another full window. Called when a + * `notifications/progress` for this request arrives, mirroring the SDK + * client's `resetTimeoutOnProgress` so the relay's own deadline never fires + * before the client's progress-aware one (#2028). A no-op when the wait was + * created without a timeout. + */ + resetTimeout: () => void; }; export class RemoteSession { @@ -172,35 +181,57 @@ export class RemoteSession { timeoutMs = 60_000, ): Promise { return new Promise((resolve, reject) => { - const timer = - timeoutMs > 0 - ? setTimeout(() => { - this.requestWaits.delete(requestId); - reject( - new Error( - `MCP request ${String(requestId)} timed out after ${timeoutMs}ms`, - ), - ); - }, timeoutMs) - : undefined; + let timer: ReturnType | undefined; + const arm = () => { + if (timeoutMs <= 0) return; + timer = setTimeout(() => { + this.requestWaits.delete(requestId); + reject( + new Error( + `MCP request ${String(requestId)} timed out after ${timeoutMs}ms`, + ), + ); + }, timeoutMs); + }; + const clear = () => { + if (timer !== undefined) { + clearTimeout(timer); + timer = undefined; + } + }; + arm(); this.requestWaits.set(requestId, { resolve: () => { - if (timer !== undefined) { - clearTimeout(timer); - } + clear(); resolve(); }, reject: (error) => { - if (timer !== undefined) { - clearTimeout(timer); - } + clear(); reject(error); }, + // A progress notification for this request re-arms the full window, so + // a tool that keeps reporting progress never trips the relay's own + // deadline — the same guarantee the SDK client's `resetTimeoutOnProgress` + // gives on a direct transport (#2028). + resetTimeout: () => { + if (timer === undefined) return; + clear(); + arm(); + }, }); }); } + /** + * Re-arm a pending request's wait timeout. Invoked from {@link onMessage} when + * a `notifications/progress` carrying this request's `progressToken` arrives. + * A no-op when no wait is pending for the id. + */ + noteRequestProgress(requestId: string | number): void { + this.requestWaits.get(requestId)?.resetTimeout(); + } + cancelRequestWait(requestId: string | number): void { const wait = this.requestWaits.get(requestId); if (!wait) { @@ -265,6 +296,15 @@ export class RemoteSession { ) { this.settleRequestWait(message.id); } + // A `notifications/progress` carries the originating request's id in + // `params.progressToken` (the SDK stamps `progressToken: messageId`). Re-arm + // that request's wait so the relay's deadline tracks the client's + // progress-aware one instead of firing at a flat 60s (#2028). Log messages + // (`notifications/message`) deliberately do NOT reset it, matching the SDK. + const progressToken = progressTokenOf(message); + if (progressToken !== undefined) { + this.noteRequestProgress(progressToken); + } this.pushEvent({ type: "message", data: message }); } diff --git a/core/mcp/remote/progressToken.ts b/core/mcp/remote/progressToken.ts new file mode 100644 index 00000000..1759e7fc --- /dev/null +++ b/core/mcp/remote/progressToken.ts @@ -0,0 +1,33 @@ +/** + * Shared helper for the remote relay's progress-aware request-response waits + * (#2028). Pure and browser-safe, so both the browser `RemoteClientTransport` + * and the Node `RemoteSession` import it rather than each carrying a copy. + */ + +import type { JSONRPCMessage } from "@modelcontextprotocol/client"; + +/** + * The id of the request a `notifications/progress` belongs to, or `undefined` + * for any other message. The SDK stamps `progressToken: messageId` on the + * outbound request, so a progress notification's `progressToken` is the id of + * the request whose wait should be re-armed. A JSON-RPC progress token is a + * string or a number; anything else is ignored so a malformed token can't be + * coerced into a map key. + */ +export function progressTokenOf( + message: JSONRPCMessage, +): string | number | undefined { + if ( + "method" in message && + message.method === "notifications/progress" && + "params" in message && + typeof message.params === "object" && + message.params !== null + ) { + const token = (message.params as { progressToken?: unknown }).progressToken; + if (typeof token === "string" || typeof token === "number") { + return token; + } + } + return undefined; +} diff --git a/core/mcp/remote/remoteClientTransport.ts b/core/mcp/remote/remoteClientTransport.ts index 9cd22460..e1480cd3 100644 --- a/core/mcp/remote/remoteClientTransport.ts +++ b/core/mcp/remote/remoteClientTransport.ts @@ -31,6 +31,7 @@ import type { RemoteSendResponse, } from "./types.js"; import { oauthTokensToRemoteAuthState } from "./types.js"; +import { progressTokenOf } from "./progressToken.js"; export interface AuthRecoveryHandlers { handleAuthChallenge( @@ -85,6 +86,12 @@ const DEFAULT_SSE_RESPONSE_TIMEOUT_MS = 60_000; type SseResponseWait = { resolve: () => void; reject: (error: Error) => void; + /** + * Re-arm this wait's timeout for another full window when a + * `notifications/progress` for the request arrives, mirroring the SDK + * client's `resetTimeoutOnProgress` (#2028). + */ + resetTimeout: () => void; }; function requestIdForMessage( @@ -524,6 +531,13 @@ export class RemoteClientTransport implements Transport { if (parsed.type === "message") { const msg = parsed.data as JSONRPCMessage; this.settleSseResponseWait(msg); + // Keep the SSE wait alive while progress flows for a long call + // (#2028) — the settle above never matches a notification, so this + // is the only place a progress note touches the wait. + const progressToken = progressTokenOf(msg); + if (progressToken !== undefined) { + this.resetSseResponseWait(progressToken); + } this.onmessage?.(msg, undefined); } else if ( parsed.type === "fetch_request" && @@ -675,14 +689,18 @@ export class RemoteClientTransport implements Transport { private waitForSseResponse(requestId: string | number): Promise { return new Promise((resolve, reject) => { - const timer = setTimeout(() => { - this.sseResponseWaits.delete(requestId); - reject( - new Error( - `Timed out waiting for MCP response on SSE (${this.sseResponseTimeoutMs}ms)`, - ), - ); - }, this.sseResponseTimeoutMs); + let timer: ReturnType; + const arm = () => { + timer = setTimeout(() => { + this.sseResponseWaits.delete(requestId); + reject( + new Error( + `Timed out waiting for MCP response on SSE (${this.sseResponseTimeoutMs}ms)`, + ), + ); + }, this.sseResponseTimeoutMs); + }; + arm(); this.sseResponseWaits.set(requestId, { resolve: () => { clearTimeout(timer); @@ -692,10 +710,22 @@ export class RemoteClientTransport implements Transport { clearTimeout(timer); reject(error); }, + // A progress notification for this request re-arms the full window so + // the browser-side deadline tracks the SDK client's progress-aware one + // rather than firing at a flat 60s (#2028). + resetTimeout: () => { + clearTimeout(timer); + arm(); + }, }); }); } + /** Re-arm a pending request's SSE wait timeout on a matching progress note. */ + private resetSseResponseWait(requestId: string | number): void { + this.sseResponseWaits.get(requestId)?.resetTimeout(); + } + private async postSend( message: JSONRPCMessage, options: TransportSendOptions | undefined,