modelcontextprotocol / modelcontextprotocol/servers
Please cut a new release of @modelcontextprotocol/server-sequential-thinking — coercion fix from #3533 not on npm
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Description
The latest npm release @modelcontextprotocol/server-sequential-thinking@2025.12.18 rejects valid tool calls from clients (e.g. Claude Code) that send nextThoughtNeeded, thoughtNumber, and totalThoughts as strings:
MCP error -32602: Input validation error
nextThoughtNeeded: expected boolean, received string
thoughtNumber: expected number, received string
totalThoughts: expected number, received string
This was reported in #3428 and fixed by #3533 (merged 2026-03-15) which switches the schema to z.coerce.number() and a coercedBoolean helper. The fix is on main but has not been published — 2025.12.18 is still the latest tag on npm, so npx -y @modelcontextprotocol/server-sequential-thinking continues to pull the broken build.
Request: cut a new release (e.g. 2025.12.19 or 2026.3.x) so downstream users get the fix without having to pin to 2025.11.25 or build from source.
Repro: Call the sequentialthinking tool from Claude Code with nextThoughtNeeded: false, thoughtNumber: 1, totalThoughts: 1.
Workaround: Pin to @2025.11.25 in MCP client config.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the @modelcontextprotocol/server-sequential-thinking package, its current 2025.12.18 npm release, and the fix from #3533 on main. Check the repository's release path and verify the sequentialthinking repro accepts string values after a new release is published to npm.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript
- Domain
- release
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Active
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100