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MCPX_QUARANTINE_TOOL_CHANGED

Severity: warn Domain: Quarantine

What happened​

mcpproxy hashes the description and JSON schema of every tool at approval time. On every reconnect / poll, it re-hashes and compares. A tool whose hash changed is rug-pull-protected: it will not run until you re-approve it.

This catches the case where a previously-trusted MCP server silently swaps a tool's instructions to inject malicious behaviour into AI agents.

How to fix​

Review the diff​

mcpproxy upstream inspect <server-name>             # marks tools as "changed"
curl -H "X-API-Key: $KEY" \
  "http://127.0.0.1:8080/api/v1/servers/<id>/tools/<tool>/diff"

The web UI's Quarantine panel renders the diff side-by-side.

Re-approve​

If the change is legitimate (vendor updated the docstring, added a new parameter, etc.):

mcpproxy upstream approve <server-name> --tool <tool-name>
mcpproxy upstream approve <server-name>             # approves all changed/pending

If the change is not legitimate​

Disable or quarantine the server entirely until you understand what changed:

mcpproxy upstream disable <server-name>
mcpproxy upstream quarantine <server-name>

Then file an issue with the upstream maintainer.