Question 1

What is MCP tool drift?

Accepted Answer

MCP tool drift is any change to an MCP server's tool manifest - a tool's name, description, or input schema - after you first approved the server. Because an agent reads tool descriptions as instructions, a description that changes after approval can silently alter what your agent does. Drift is detected by baselining the tools/list response and diffing it on later checks.

Question 2

How do I check if an MCP server changed its tools?

Accepted Answer

Baseline the server's tool manifest once, then compare on each later check. Dominion Observatory's free drift check does this: fetch https://dominionobservatory.com/api/drift?server=<your-mcp-url> to get the current manifest, a signed baseline hash, and whether it drifted since the last check. No signup or key is required.

Question 3

What is MCP tool poisoning?

Accepted Answer

Tool poisoning is when an MCP server ships a tool description or schema - after you approved it - that steers the agent into harmful actions such as leaking data or calling the wrong tool. It is a rug-pull class attack: a one-time code scan or install review cannot see it because the malicious change arrives later over the wire. Baseline-and-diff drift detection catches it.

Question 4

Is the MCP drift check free?

Accepted Answer

Yes. The one-time drift check and the /api/drift API are free with no signup. Continuous monitoring - re-checked about every 20 minutes with webhook and email alerts on any change plus a signed attestation trail - is a paid plan at $29/month per server.

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