"Sanity" matching MCP servers:

• json-sanity

  peak-agent

  A

  license

  -

  quality

  C

  maintenance

  Deterministic JSON validation and repair for AI agents. Validates, repairs, schema-checks, and diffs JSON so long-running agents don't corrupt their session state with malformed writes.

  Last updated 2026-06-12

  MIT

• Salyut

  XenaRathon

  A

  license

  -

  quality

  B

  maintenance

  Fans out queries to multiple independent free LLMs from different providers and returns their answers side by side, enabling sanity-checking of decisions or getting multiple perspectives during coding sessions.

  Last updated 2026-07-13

  GPL 3.0

• arXiv Discovery MCP

  loganrooks

  A

  license

  -

  quality

  B

  maintenance

  MCP server for discovering, triaging, and monitoring arXiv papers with transparent interest modeling and inspectable ranking.

  Last updated 2026-06-20

  MIT