MCPGuard: conformance gaps in Python and TypeScript MCP SDKs

Evidence record

Preprint header dates 12 August; reports 13 Python SDK and 19 TypeScript SDK conformance gaps, researcher reproduction and maintainer confirmation.

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Claim-level citations (3)

• supportsMCPGuard finds protocol-rule omissions beneath apparently passing SDK conformance suites: MCPGuard authors report 13 specification-conformance findings in Python SDK 1.26.0 and 19 in TypeScript SDK 1.29.0, with structural PoCs and targeted review of behavioral constraints.

  Abstract; Section V-B Conformance gap findings, Table II

• supportsMCPGuard finds protocol-rule omissions beneath apparently passing SDK conformance suites: In the paper evaluation, two endpoint-oriented conformance baselines found none of the 32 SDK-level gaps even though the official suite passed its applicable checks.

  Section V-C Comparison with Baselines; Table IV

• supportsMCPGuard finds protocol-rule omissions beneath apparently passing SDK conformance suites: MCPGuard authors classify 27 findings as structural constraint gaps and five as behavioral rule gaps across the Python and TypeScript SDKs; their analysis covered 349 of 485 behavioral specification units in Python and 339 of 485 in TypeScript, leaving unexamined rules outside the reported findings.

  Evaluation Section V-B, Table II Aggregate distribution; Table I Specification-to-SDK analysis coverage