# io.github.polygraphso/litmus

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

- name: io.github.polygraphso/litmus
- version: 0.36.0
- connection class: R0 (autonomous)
- trust: 90/100
- quality: 84/100 (good)
- owner: not claimed
- descriptor: https://api.protogrid.dev/v1/servers/io.github.polygraphso%2Flitmus
- tools: https://api.protogrid.dev/v1/servers/io.github.polygraphso%2Flitmus/tools

**An agent can connect right now, no human step.** Remote endpoint, no authentication, reachable on the last probe.

## Connection (mcpServers)

```json
{
  "mcpServers": {
    "litmus": {
      "type": "http",
      "url": "https://polygraph.so/api/mcp"
    }
  }
}
```


## Trust

- hygiene: 100
- liveness: 100
- freshness: 65
- provenance: 90
- drivers: +repository +namespace-matches-repo +website +reachable +uptime-100% ~updated-92d-ago
- Derived from observable signals (official registry feed and our own credential-free probes); no code audit performed.

## Quality 84/100 (good)

### protocol: 75 (weight 25)

- warn `protocol.modern`: newest supported version is 2025-11-25; 2026-07-28 not supported, older versions are deprecated until 2027-07-28
- n/a `protocol.stateless`: only applies to 2026-07-28 servers
- pass `protocol.transport`: streamable HTTP
- n/a `protocol.list_ttl`: only applies to 2026-07-28 servers

### authorization: n/a (weight 15)

- n/a `auth.prm`, `auth.as_metadata`, `auth.cimd`: no remote uses OAuth
- n/a `auth.secret_in_url`: no templated URL

### tool hygiene: 93 (weight 30)

- pass `tools.descriptions`: every tool has a description
- pass `tools.description_length`: descriptions are concise
- pass `tools.schemas`: every tool has an object input schema
- pass `tools.annotations`: 3 of 3 tools declare readOnlyHint or destructiveHint
- warn `tools.directory_hints`: 1 of 3 tools declare all four hints; missing: check_server (destructiveHint, idempotentHint); list_servers (destructiveHint, idempotentHint)
- pass `tools.token_cost`: about 574 tokens to load every tool
- pass `tools.api_dump`: tools are not a one-to-one API dump

### stability: 100 (weight 15)

- pass `stability.changes`: no tool changes in 30 days
- pass `stability.rug_pull`: no tool changed its meaning under the same name

### dependencies: 67 (weight 15)

- pass `deps.known_vulns`: no known advisory in 136 resolved packages
- fail `deps.mcp_sdk_version`: @modelcontextprotocol/sdk 1.30.1 has 1 known advisory (GHSA-6qxp-vccf-f47h); update @modelcontextprotocol/sdk to 1.31.0 or later
- pass `deps.resolvable`: @polygraphso/litmus@0.36.0 resolved: 136 packages

- tools: 3, about 574 tokens to load them all
- tool set hash: 90df4c2b465391828533ff029cac15ef
- badge: [![protogrid quality](https://protogrid.dev/badge/io.github.polygraphso/litmus.svg)](https://protogrid.dev/servers/io.github.polygraphso/litmus)
- Checks run on what our credential-free, read-only probes observe; tools are never called and no code audit is performed.

### Tool changes

_No tool definition changes recorded._

## Dependencies

- npm @polygraphso/litmus@0.36.0: resolved, 135 dependencies, MCP SDK @modelcontextprotocol/sdk 1.30.1
  - GHSA-6qxp-vccf-f47h (high) in `` @modelcontextprotocol/sdk@1.30.1 ``, direct, fixed in `` 1.31.0 ``, advisory summary: "MCP TypeScript SDK: OAuth client could send credentials to an authorization server chosen by the MCP server" https://osv.dev/vulnerability/GHSA-6qxp-vccf-f47h

Dependency graphs from deps.dev; advisories from OSV.dev, including the GitHub Advisory Database and the PyPI Advisory Database; all CC BY 4.0.

## Remotes

- https://polygraph.so/api/mcp (streamable-http, auth none, reachable true, uptime30d 1)

## Packages

- npm @polygraphso/litmus@0.36.0

## Tools (3)

- `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.
- `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`.
- `request_grade`: Hosted grading is discontinued. This tool returns gone. Existing published grades remain available via check_server / list_servers. To grade a server yourself, run the open harness: npx -y -p @polygraphso/litmus polygraphso-litmus litmus <server_ref>.