modelcontextprotocol/typescript-sdk

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The official TypeScript SDK for Model Context Protocol servers and clients

Stars: 13.4k
Forks: 2.2k
Open beginner issues: 25
Indexed issues: 300
Avg merge: 3d 15h
Merged PRs (30d): 4

Dominant language: TypeScript
License: No license data
Last GitHub push: Sep 16, 2026
Latest indexed: Sep 20, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: good first issue help wanted

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300 open issues indexed

[v2] No supported way to emit Mcp-Param-* headers on a legacy-era connection, but GitHub's hosted server requires them there Open

needs repro question spec-2026-07-28 v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 52/100

modelcontextprotocol/typescript-sdk#2639 · Opened Aug 11, 2026
[v2] Tasks extension: tools/call rejects CreateTaskResult but accepts an omitted discriminator as complete Open

enhancement spec-2026-07-28 v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2637 · 1 reaction · Opened Aug 10, 2026
zod v4: "additionalProperties: false" missing Open

question v1 v2

Difficulty 3/5 1-2 days Newbie friendliness 58/100

modelcontextprotocol/typescript-sdk#2636 · 2 comments · Opened Aug 10, 2026
Low-level Server API publishes inputSchema in tools/list but does not enforce it on tools/call Open

enhancement needs design v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2628 · 1 comment · Opened Aug 9, 2026
Docs: passing z.object() as inputSchema on v1 fails silently (empty schema) or cryptically (tools/list crash) — not covered in troubleshooting or migration guide Open

documentation enhancement good first issue P3 v1 v2

Difficulty 2/5 1-3 hours Newbie friendliness 85/100

modelcontextprotocol/typescript-sdk#2627 · 4 comments · Opened Aug 9, 2026
oauthMetadataResponse requires a full AS metadata document to read one field from it Open

auth enhancement P2 ready for work v1 v2

modelcontextprotocol/typescript-sdk#2623 · 1 assignee · Opened Aug 7, 2026
McpServer constructor capabilities.tools.listChanged is silently overridden by setToolRequestHandlers() Open

bug P3 ready for work v1

Difficulty 3/5 1-2 days Newbie friendliness 72/100

modelcontextprotocol/typescript-sdk#2622 · 1 comment · Opened Aug 7, 2026
[v2] versionNegotiation: 2xx server/discover response with an empty or unparseable body fails connect() instead of falling back to legacy initialize Open

spec-2026-07-28 v2

Difficulty 3/5 1-2 days Newbie friendliness 68/100

modelcontextprotocol/typescript-sdk#2619 · Opened Aug 6, 2026
[v2] Legacy Streamable HTTP reconnects continue after the client request times out Open

v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2615 · Opened Aug 5, 2026
Client.listTools() corrupts its cached tool metadata when an output schema fails to compile Open

bug P3 ready for work v1

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

modelcontextprotocol/typescript-sdk#2614 · 1 comment · Opened Aug 4, 2026
Client.callTool() throws -32602 after tools/list_changed replaces an in-flight call's output schema Open

bug P2 ready for work v1

Difficulty 2/5 1-3 hours Newbie friendliness 84/100

modelcontextprotocol/typescript-sdk#2612 · 1 comment · Opened Aug 4, 2026
createMcpHandler: reused McpServer instance grows an unbounded onclose chain — memory leak, then uncatchable RangeError after ~20k requests Open

bug P2 ready for work spec-2026-07-28 v2

Difficulty 4/5 3-5 days Newbie friendliness 55/100

modelcontextprotocol/typescript-sdk#2607 · 1 comment · 3 reactions · Opened Aug 2, 2026
Memory leak: `AjvJsonSchemaValidator.getValidator()` recompiles schemas without `$id` on every call Open

bug P2 ready for work v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 52/100

modelcontextprotocol/typescript-sdk#2605 · 1 comment · Opened Aug 2, 2026
CODEOWNERS auth paths do not resolve on main, so the auth team is never auto-requested Open

auth bug P3 ready for work v2

modelcontextprotocol/typescript-sdk#2604 · 1 comment · 1 assignee · Opened Aug 2, 2026
v2: extension methods shadowed by legacy spec-method registry — custom tasks/get & tasks/cancel handlers unreachable (-32601 before handler lookup) Open

bug needs design spec-2026-07-28 v2

Difficulty 4/5 3-5 days Newbie friendliness 55/100

modelcontextprotocol/typescript-sdk#2598 · 3 comments · Opened Aug 1, 2026
OAuth: isLoopbackHost rejects *.localhost subdomains, breaking host-based local dev (InsecureTokenEndpointError) Open

spec-2026-07-28 v2

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

modelcontextprotocol/typescript-sdk#2591 · 4 comments · 4 reactions · Opened Jul 31, 2026
`_onprogress` raises a protocol error for a race servers cannot avoid (progress notification arriving with the response) Open

bug P2 ready for work v1 v2

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

modelcontextprotocol/typescript-sdk#2580 · 4 comments · Opened Jul 30, 2026
Implement SEP-1933: Workload Identity Federation (Extension) Open

auth enhancement P2 ready for work v1 v2

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/typescript-sdk#2576 · Opened Jul 29, 2026
codemod v1-to-v2 hoists rewritten imports above the file's license header Open

bug P2 ready for work v2

Difficulty 3/5 1-2 days Newbie friendliness 67/100

modelcontextprotocol/typescript-sdk#2575 · 2 comments · Opened Jul 29, 2026
subscriptions/listen cannot carry extension notifications (blocks notifications/tasks) Open

enhancement needs design spec-2026-07-28 v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2569 · 1 comment · Opened Jul 28, 2026
normalizeHeaders references the bare global `HeadersInit`, breaking Node-only consumers with skipLibCheck: false Open

bug P2 ready for work v1

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

modelcontextprotocol/typescript-sdk#2568 · 1 comment · Opened Jul 28, 2026
Streamable HTTP: pre-existing hardening items from the #2547 review Open

bug P2 ready for work v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2562 · 2 comments · Opened Jul 27, 2026
InMemoryEventStore: standalone-stream resume broken by getStreamIdFromEventId split Open

bug P2 ready for work v1 v2

Difficulty 2/5 1-3 hours Newbie friendliness 74/100

modelcontextprotocol/typescript-sdk#2560 · 1 comment · Opened Jul 27, 2026
Streamable HTTP: JSON-response-mode stream mappings never complete their lifecycle Open

bug P2 ready for work v1 v2

Difficulty 3/5 1-2 days Newbie friendliness 68/100

modelcontextprotocol/typescript-sdk#2559 · 5 comments · Opened Jul 27, 2026
Streamable HTTP: close replayed request streams once no in-flight requests remain Open

bug P2 ready for work v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 52/100

modelcontextprotocol/typescript-sdk#2558 · 4 comments · Opened Jul 27, 2026
Web-standard SSE responses override the HTTP server keep-alive lifetime Open

bug P3 ready for work v1 v2

Difficulty 3/5 1-2 days Newbie friendliness 68/100

modelcontextprotocol/typescript-sdk#2553 · 2 comments · Opened Jul 27, 2026
Widen @hono/node-server range to ^1.19.9 || ^2 so GHSA-frvp-7c67-39w9 is reachable (npm suggests a breaking downgrade) Open

bug P2 ready for work v2

Difficulty 2/5 1-3 hours Newbie friendliness 74/100

modelcontextprotocol/typescript-sdk#2548 · 3 comments · Opened Jul 24, 2026
[v2] Server: print warning if `sendResourceUpdated` is used but `subscribe` is not set Open

spec-2026-07-28 v1 v2

Difficulty 3/5 1-2 days Newbie friendliness 55/100

modelcontextprotocol/typescript-sdk#2545 · 1 comment · Opened Jul 24, 2026
[v2] MRTR wipe-cache example reads unvalidated elicitation content and defaults malformed scope to all Open

spec-2026-07-28 v2

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

modelcontextprotocol/typescript-sdk#2542 · 3 comments · Opened Jul 24, 2026
stdio.ts/ReadBuffer retains consumed input and copies the next stdio chunk Open

bug P3 ready for work v1 v2

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

modelcontextprotocol/typescript-sdk#2536 · 1 comment · Opened Jul 23, 2026
Widen `@hono/node-server` range: `^1.19.9` cannot resolve past GHSA-frvp-7c67-39w9 (no patched 1.x) Open

bug fix proposed P2 ready for work v2

Difficulty 3/5 1-2 days Newbie friendliness 68/100

modelcontextprotocol/typescript-sdk#2531 · 2 comments · 12 reactions · Opened Jul 21, 2026
Bug/Feature Request: Node 26 fetch HTTP/2 SSE stream buffering hangs MCP connections Open

bug v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/typescript-sdk#2526 · Opened Jul 21, 2026
Bug/Feature Request: Node 26 fetch HTTP/2 SSE stream buffering hangs MCP connections Open

bug needs repro v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2525 · Opened Jul 21, 2026
[v2] Multiple connect per server Open

v1 v2

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/typescript-sdk#2515 · Opened Jul 18, 2026
Mid-session re-auth after refresh-token expiry dead-ends: send() gets "REDIRECT" and throws UnauthorizedError without ever exchanging the new code Open

auth bug needs design v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 58/100

modelcontextprotocol/typescript-sdk#2510 · 2 comments · Opened Jul 17, 2026
Add a high-level MCP operation interceptor seam Open

enhancement v1 v2

Difficulty 5/5 Over a week Newbie friendliness 42/100

modelcontextprotocol/typescript-sdk#2507 · Opened Jul 16, 2026
v2: setRequestHandler/setNotificationHandler require a method-string literal — re-accept the schema object (or export typed method tokens) Open

enhancement needs design v2

Difficulty 5/5 Over a week Newbie friendliness 38/100

modelcontextprotocol/typescript-sdk#2505 · Opened Jul 15, 2026
Bug: Resumption token dropped when a resumed SSE stream disconnects before any id-bearing event Open

bug P2 ready for work v1 v2

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

modelcontextprotocol/typescript-sdk#2499 · 1 comment · Opened Jul 14, 2026
[v2] Declaration source maps (.d.cts.map/.d.mts.map) reference unshipped src/ with empty sourcesContent — dangling for consumers Open

v1 v2

Difficulty 5/5 Over a week Newbie friendliness 35/100

modelcontextprotocol/typescript-sdk#2491 · 1 comment · Opened Jul 14, 2026
[v2] Origin and Host validators accept userinfo before allowlisted hostnames Open

v1 v2

Difficulty 2/5 1-3 hours Newbie friendliness 65/100

modelcontextprotocol/typescript-sdk#2489 · 1 comment · Opened Jul 14, 2026
Streamable HTTP server accepts invalid media types by Accept-header substring Open

v1 v2

Difficulty 3/5 1-2 days Newbie friendliness 78/100

modelcontextprotocol/typescript-sdk#2480 · Opened Jul 13, 2026
zod v4: toJSONSchema options are hardcoded — z.date() breaks tools/list; output schemas advertise required/closed shapes the raw structuredContent can't satisfy Open

bug fix proposed P2 ready for work v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 55/100

modelcontextprotocol/typescript-sdk#2464 · 1 comment · Opened Jul 8, 2026
streamable HTTP server: no duplicate-in-flight request-id guard — concurrent POSTs with the same JSON-RPC id cross-wire responses Open

bug fix proposed P2 ready for work v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2433 · 3 comments · Opened Jul 3, 2026
[v2] feedback: Client sends legacy `initialize` to non-conforming "MCP" endpoint — no dual-era probe Open

bug documentation P3 ready for work spec-2026-07-28 v1 v2

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/typescript-sdk#2410 · 7 comments · Opened Jul 1, 2026
OAuth token exchange crashes on gzip-compressed token response (JSON.parse on undecompressed bytes) Open

auth bug needs repro v1 v2

Difficulty 3/5 1-2 days Newbie friendliness 68/100

modelcontextprotocol/typescript-sdk#2408 · 2 comments · Opened Jul 1, 2026
`McpServer` does not implement server-side pagination for list operations Open

enhancement needs decision P2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

modelcontextprotocol/typescript-sdk#2352 · 2 comments · Opened Jun 23, 2026
creation of a tool without any server instance knowledge Open

enhancement needs decision P3

Difficulty 4/5 3-5 days Newbie friendliness 45/100

modelcontextprotocol/typescript-sdk#2298 · 2 comments · 2 reactions · Opened Jun 15, 2026
Spec-method requests with invalid params answer -32603 instead of -32602 Open

bug fix proposed P2 ready for work v2 v2-fixes

Difficulty 3/5 1-2 days Newbie friendliness 76/100

modelcontextprotocol/typescript-sdk#2284 · 6 comments · Opened Jun 12, 2026
Root package export points to missing dist index files Open

bug fix proposed P1 ready for work

Difficulty 3/5 1-2 days Newbie friendliness 70/100

modelcontextprotocol/typescript-sdk#2273 · 3 comments · 1 reaction · Opened Jun 9, 2026
KIMI mcp integration fix Open

potentially close

Difficulty 3/5 1-2 days Newbie friendliness 45/100

modelcontextprotocol/typescript-sdk#2257 · 1 comment · Opened Jun 6, 2026

modelcontextprotocol/typescript-sdk

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