Credence

Check MCP servers and AI tools against the Credence trust registry before you install them.

When to use this skill

• Before installing any MCP server
• When a user asks you to add an MCP server or AI tool
• When you want to verify whether a tool is safe
• When the user asks /credence

How it works

Credence scans MCP servers and AI tools for security issues, verifies their provenance, and checks behavioral risk. Every scanned tool gets a trust score from 0 to 100 and a verdict:

Instructions

Check a server by name or URL

Fetch the Credence registry and look up the server:

curl -s "https://raw.githubusercontent.com/pestafford/credence-registry/main/registry/index.json"

Search the servers array for a match on server_id, server_name, canonical_name, or repo_url. The match does not need to be exact — partial matches on the repo URL or server name are fine.

If found, report:

Credence: <server_name>
  Score: <trust_score>/100
  Verdict: <thinktank_verdict>
  Scanned: <attested_at>
  Registry: https://credence.securingthesingularity.com/registry.html

Then give your recommendation:

• APPROVED (90+): Safe to install. Proceed.
• CONDITIONAL (70-89): Mention the score and suggest the user review the registry page for details before installing.
• FLAGGED (40-69): Warn the user. Do not install without explicit confirmation.
• REJECTED (0-39): Do not install. Explain that Credence found serious issues.

This tool has not been scanned by Credence yet.
Submit it for scanning at: https://credence.securingthesingularity.com/#submit

Then let the user decide whether to proceed.

Check before installing

Whenever you are about to install or connect to an MCP server (via claude mcp add, editing claude_desktop_config.json, or any other method), check it against Credence first. If the server is not in the registry, tell the user it hasn't been scanned and ask if they want to proceed anyway.

Get full details

For more detail on a specific server, fetch its attestation file. The attestation_file path from the index entry is relative to:

https://raw.githubusercontent.com/pestafford/credence-registry/main/registry/

The attestation includes the full score breakdown (security, provenance, behavioral), scan metadata, and the deliberation verdict.

Examples

User says: "Add the filesystem MCP server"

• Fetch the registry index
• Find modelcontextprotocol/servers/filesystem — score 88, APPROVED
• Report: "Credence score: 88/100 (APPROVED). Safe to install."
• Proceed with the install

• Fetch the registry index
• Not found
• Report: "This server hasn't been scanned by Credence yet. You can submit it at https://credence.securingthesingularity.com/#submit — want to install anyway?"

• Fetch the registry index
• Find it — score 98, APPROVED
• Report the full status

Notes

• The registry is public and requires no authentication
• Scores are based on automated scanning plus adversarial AI deliberation
• A missing entry does not mean a tool is dangerous — it just hasn't been scanned yet
• For the full methodology, see https://credence.securingthesingularity.com/faq.html