modelcontextprotocol/typescript-sdk
Watch
1
0
Fork
You've already forked typescript-sdk
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 1

fix: handle cancellation for request ID 0 (#2654)

Browse source 
Co-authored-by: Konstantin Konstantinov <konstantin@mach5technology.com>
Co-authored-by: Konstantin Konstantinov <KKonstantinov@users.noreply.github.com>
This commit is contained in:
pshah19 2026-08-16 02:17:04 -07:00 • committed by GitHub
commit 03842cd9ca
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 85 additions and 41 deletions
Download patch file Download diff file Expand all files Collapse all files

12
.changeset/cancelled-request-id-zero.md Normal file
View file

@ -0,0 +1,12 @@
---
'@modelcontextprotocol/core-internal': patch
'@modelcontextprotocol/client': patch
'@modelcontextprotocol/server': patch
---
Treat request id `0` as a real id. Two guards tested a `RequestId` for truthiness, so the legal JSON-RPC ids `0` and `''` were read as absent. Id `0` is not a corner case: the outbound request counter is zero-based, so it is the first id every peer assigns, which on the server→client leg is the first `sampling/createMessage`, `elicitation/create`, or `roots/list` a server sends.
- `notifications/cancelled` carrying id `0` was ignored, and the in-flight handler ran to completion with its `AbortSignal` never fired.
- A notification sent with `relatedRequestId: 0` wrongly passed the debounce gate (for methods opted into `debouncedNotificationMethods`). Because the pending set is keyed by method alone, a second such notification in the same tick was silently dropped rather than sent.
Absent is now the only value that means "no id".