All terms
Agent Security

Drift Detection (MCP)

Monitoring for changes in MCP server tool signatures after approval — new tools added, tool schemas modified, endpoints changed. Alerts fire so teams can re-evaluate before the agent uses new tools.


Drift detection for MCP servers continuously monitors approved tool signatures for changes. When a server adds new tools, modifies existing tool schemas, or changes endpoints after initial approval, drift detection fires an alert — so teams can re-evaluate before the agent calls the new tool.

The rug-pull vector

An MCP server that was approved with 3 benign tools (read docs, search, summarize) might silently add a 4th tool: "delete_all_documents." Without drift detection, the agent will discover and use the new tool immediately — and the admin who approved the server may never know.

Detection strategy

WardenAuth fingerprints every MCP server at registration time — recording the full tool catalog, each tool's input/output schema, and available endpoints. Continuous monitoring compares the live server state against the approved fingerprint and alerts on any diff.