fix(client): pin output schema for in-flight tool calls (v1.x)

[OllieinCanada]

Summary

• capture a tool's cached output validator before dispatching tools/call
• keep an in-flight response tied to the schema generation that was active when the call began
• add a deterministic regression that refreshes the tool catalog while the first call is parked, then verifies the first call uses the old schema and the next call uses the new one
• add a patch changeset for @modelcontextprotocol/sdk

Why this ordering matters

Client.callTool() currently checks required-task metadata before sending the request, but reads the output validator only after the response arrives. A concurrent listTools() refresh can replace that cache in between, so a valid response may be rejected against a schema that did not exist when the call was dispatched.

The validator is immutable for the lifetime of a call now: it is captured alongside the other dispatch-time metadata, without preventing later calls from using a refreshed catalog.

Fixes #2612.

Validation

• regression on unmodified v1.30.0: fails with McpError -32602 against the newer schema
• focused regression after the change: passes
• client suite: 69/69 passed
• npm run typecheck
• npx eslint src/
• npx prettier --check .
• npx tsc -p tsconfig.prod.json
• npx tsc -p tsconfig.cjs.json

Local full-suite note

On this Windows host (Node 20.9.0), the resource-safe full run completed with 1,612 passing tests and four unrelated integration timeouts in processCleanup.test.ts and the Zod v3 half of taskResumability.test.ts; Windows stdio teardown also emitted two pipe errors. The installed Vite/Undici dev dependencies warn that this local Node version is below their current supported 20.x patch level. The changed client suite is green, and the upstream Linux CI matrix is the authoritative full-suite result.

[changeset-bot]

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Latest commit: a992ad4

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commit: a992ad4