Litmus MCP

Litmus is an open behavioral harness for MCP servers that grades them from A to F. It provides tools for agents to look up published grades, list graded servers, request new grades, and run the full grading harness locally to evaluate server behavior and tool surfaces.

Package and access

Local package with source-attributed installation metadata. Koskamo does not execute packages during review.

Community listingLocal stdioSource reviewed; not executedPublished by polygraphso

Vendor documentation

What you can do with it

Look up a server's published grade instantly
List servers with published grades filtered by score
Run the full behavioral grading harness on a server
Request a new grade for a server via payment

Source and maintenance

Community listingRegistry 0.36.0

mcp-registry: io.github.polygraphso/litmus@0.36.0 Source repository Project website

Maintenance checked: Oct 31, 2026, 10:59 PM UTC

Packages and installation

Source-provided package data. Koskamo has not executed or live-probed this package.

@polygraphso/litmus 0.36.0

npm

@polygraphso/litmus package definition

{
  "version": "0.36.0",
  "transport": "stdio",
  "identifier": "@polygraphso/litmus",
  "registryType": "npm",
  "registryBaseUrl": "https://registry.npmjs.org",
  "packageArguments": [
    {
      "type": "positional",
      "value": "polygraphso-litmus-mcp"
    }
  ],
  "environmentVariables": [
    {
      "name": "POLYGRAPH_API_URL",
      "default": "https://polygraph.so",
      "description": "Base URL for published-grade lookups (check_server, list_servers, request_grade) and attestation resolution."
    },
    {
      "name": "NEXT_PUBLIC_POLYGRAPH_NETWORK",
      "default": "base",
      "description": "Which network to read attestations from: 'base' (mainnet, default) or 'base-sepolia' (testnet)."
    }
  ]
}

Tools

Reported by the attributed source; not independently observed by Koskamo.

No tool definitions available.

Connect from your client

Each snippet configures the same source-provided package; replace placeholders before use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Cursor

Merge this local stdio configuration, replace every placeholder environment value, and restart Cursor. Koskamo has not executed this package.

Cursor configuration

{
  "mcpServers": {
    "litmus-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@polygraphso/litmus@0.36.0",
        "polygraphso-litmus-mcp"
      ],
      "env": {
        "POLYGRAPH_API_URL": "<YOUR_POLYGRAPH_API_URL>",
        "NEXT_PUBLIC_POLYGRAPH_NETWORK": "<YOUR_NEXT_PUBLIC_POLYGRAPH_NETWORK>"
      }
    }
  }
}

Cline

Merge this local stdio configuration, replace every placeholder environment value, and restart Cline. Koskamo has not executed this package.

Cline configuration

{
  "mcpServers": {
    "litmus-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@polygraphso/litmus@0.36.0",
        "polygraphso-litmus-mcp"
      ],
      "env": {
        "POLYGRAPH_API_URL": "<YOUR_POLYGRAPH_API_URL>",
        "NEXT_PUBLIC_POLYGRAPH_NETWORK": "<YOUR_NEXT_PUBLIC_POLYGRAPH_NETWORK>"
      }
    }
  }
}

VS Code

Merge this local stdio configuration, replace every placeholder environment value, and restart VS Code. Koskamo has not executed this package.

VS Code configuration

{
  "servers": {
    "litmus-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@polygraphso/litmus@0.36.0",
        "polygraphso-litmus-mcp"
      ],
      "env": {
        "POLYGRAPH_API_URL": "<YOUR_POLYGRAPH_API_URL>",
        "NEXT_PUBLIC_POLYGRAPH_NETWORK": "<YOUR_NEXT_PUBLIC_POLYGRAPH_NETWORK>"
      }
    }
  }
}

Claude Desktop

Merge this local stdio configuration, replace every placeholder environment value, and restart Claude Desktop. Koskamo has not executed this package.

Claude Desktop configuration

{
  "mcpServers": {
    "litmus-mcp": {
      "command": "npx",
      "args": [
        "-y",
        "@polygraphso/litmus@0.36.0",
        "polygraphso-litmus-mcp"
      ],
      "env": {
        "POLYGRAPH_API_URL": "<YOUR_POLYGRAPH_API_URL>",
        "NEXT_PUBLIC_POLYGRAPH_NETWORK": "<YOUR_NEXT_PUBLIC_POLYGRAPH_NETWORK>"
      }
    }
  }
}

Let your agent find its tools

Find servers like Litmus MCP from your agent. Add Koskamo once to search the index for endpoints, access requirements, and client setup. Public discovery needs no key.

Connect Koskamo Explore workflows

See all 7,560