fix: widen requestedSchema type to accept additional JSON Schema fields #1511
+24
−7
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
The `requestedSchema` object in `ElicitRequestFormParamsSchema` was too narrow, rejecting valid JSON Schema fields like `additionalProperties` that Zod v4's `.toJSONSchema()` and other JSON Schema generators produce. Add `.passthrough()` to the `requestedSchema` Zod object and include the `$schema` field (already present in the spec types) so that standard JSON Schema output is accepted without type errors. Fixes modelcontextprotocol#1362 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
🦋 Changeset detectedLatest commit: 9b4547d The changes in this PR will be included in the next version bump. This PR includes changesets to release 1 package
Not sure what this means? Click here to learn what changesets are. Click here if you're a maintainer who wants to add another changeset to this PR |
@modelcontextprotocol/client
@modelcontextprotocol/server
@modelcontextprotocol/express
@modelcontextprotocol/hono
@modelcontextprotocol/node
commit: |
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary
Fixes #1362
The
requestedSchematype inElicitRequestFormParamsSchemawas too narrow — it rejected valid JSON Schema fields likeadditionalPropertiesand$schemathat Zod v4's.toJSONSchema()(and other JSON Schema generators) produce. This worked fine at runtime but caused TypeScript errors when users passed generated schemas directly.Changes:
.passthrough()to therequestedSchemaZod object so additional JSON Schema fields are accepted at both the type and runtime level$schemafield to the Zod schema (already present inspec.types.tsbut was missing from the Zod schema)spec.types.test.tswith aFixSpecRequestedSchemahelper type to account for the passthrough index signature (follows existing pattern used forServerCapabilities)Before:
requestedSchema: { type: 'object', properties: {...}, additionalProperties: false }causes a TypeScript errorAfter: Extra JSON Schema fields are accepted without type errors
Test plan
pnpm --filter @modelcontextprotocol/core test)pnpm typecheck:all)pnpm lint:all)🤖 Generated with Claude Code