io.github.polygraphso/litmus

pkg:npm:@polygraphso/litmus

Grade MCP servers A to F with the open behavioral litmus. npm: full toolset; hosted: lookups only.

transport:: remote + stdio
credential class:: self-provisionable
repo:: https://github.com/polygraphso/litmus

Owner verification

Not yet verified. Verifying proves you control this server and is free, permanently — it never changes a published score.

Start verification →

Tools

check_server
Read a server's published behavioral grade (A-F) from polygraph.so in under a second; no execution. The pre-flight check before recommending or installing an MCP server. On a miss it returns not_available (unevaluated: neither safe nor unsafe) with next steps.
shallow
list_servers
Servers with a published polygraph grade, sorted A-first then by ref. Returns up to `limit` rows starting at `offset` (default limit 25, capped at 100 per call); `grade` restricts to one letter. `summary` always covers the full graded corpus (a total plus a count per grade), regardless of `grade`, `limit`, or `offset`.
shallow
request_grade
Record a grade request with polygraph.so. Recording is free; only real, plausibly-MCP targets are accepted. Grading starts once the request's one-time $1 USD fee is paid: payment.payUrl is the human/browser checkout (paid in $POLYGRAPH), and payment.x402Url is the agent rail, POST the same request body there with an x402-capable client. A bare POST to x402Url returns a 402 with the exact payment requirements; retry with an X-PAYMENT header. Asset is USDC on Base mainnet (eip155:8453). On the x402 rail settlement is deferred: the authorization is charged only once a grade lands, and a run the harness cannot complete voids it, so nothing is charged. Paying starts a 48h grading clock. The fee buys the run, never the grade. After paying, poll check_server with the same server_ref for the published result, or poll statusUrl for progress.
shallow

Embed this server’s score

Tool count and median score across every tool in this server’s corpus — honest in a way a single cherry-picked tool’s badge wouldn’t be.

[![Vouch score](https://vouch.tools/api/servers/f67b0f4c-d4f8-470e-8b38-2ca5c25312eb/badge.svg)](https://vouch.tools/servers/f67b0f4c-d4f8-470e-8b38-2ca5c25312eb)