fix(validators): cache compiled schemas to prevent memory leak (#2605) - #2626
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elang2 wants to merge 2 commits into
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fix(validators): cache compiled schemas to prevent memory leak (#2605)#2626elang2 wants to merge 2 commits into
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… leak (modelcontextprotocol#2605) Add content-keyed caches to AjvJsonSchemaValidator and CfWorkerJsonSchemaValidator so that schemas without $id are not recompiled on every getValidator() call. This prevents Ajv's internal scope from growing without bound in long-running MCP clients that periodically refresh their tool catalogue. The cache key is the JSON-serialised schema content. Schemas with $id continue to use Ajv's built-in identity cache. Non-serialisable schemas (cyclic, BigInt) fall back to uncached compilation.
🦋 Changeset detectedLatest commit: f5a482f The changes in this PR will be included in the next version bump. This PR includes changesets to release 6 packages
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@modelcontextprotocol/client
@modelcontextprotocol/codemod
@modelcontextprotocol/core
@modelcontextprotocol/server
@modelcontextprotocol/server-legacy
@modelcontextprotocol/express
@modelcontextprotocol/fastify
@modelcontextprotocol/hono
@modelcontextprotocol/node
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Summary
Schemas without a
$idfield were being recompiled on everygetValidator()call, leaking Ajv instances over the lifetime of a long-running server. This adds a content-keyed compilation cache to bothAjvSchemaValidatorProviderandCfWorkerSchemaValidatorProvider.Cache key uses
JSON.stringify(schema)so mutated schemas get a fresh compilation rather than a stale cache hit. Non-serializable schemas (cyclic refs, BigInt) fall back gracefully to uncached compilation.Test plan
validatorCaching.test.tscovering cache hits, content changes,$idpreservation, mutation safety, and error isolationFixes #2605