What is Agent Observability?
Understanding an agent's behaviour through external outputs — logs, metrics, traces, and audit trails. For MCP-based agents, observability means tracking every tool call, its arguments, the policy decision (allow/deny), and the outcome.
WHY IT MATTERS
You cannot secure what you cannot see. Observability provides visibility to understand agent behaviour, detect anomalies, debug issues, and prove compliance.
For agents using MCP tools, the critical observability data is: which tool was called, with what arguments, whether the policy allowed or denied it, what the server returned, and when all of this happened. This trail connects the agent's intent to the actual outcome.
Observability enables iterative policy refinement. By reviewing which tools an agent actually uses, which calls are being denied, and which argument patterns emerge, operators can tune YAML policies to be as permissive as needed and as restrictive as possible.
HOW POLICYLAYER USES THIS
PolicyLayer provides comprehensive audit trails for every MCP tool call. Each call is logged with: tool name, arguments, policy decision (allow/deny), the specific policy rule that matched, timestamp, and latency. These logs provide complete visibility into what agents are doing and what policies are governing them. Export to standard observability platforms for dashboards and alerting.