Audit Log Integrity (Claude Managed Agent)

Overview

The Audit Log Integrity (Claude Managed Agent) evaluation verifies that the Anthropic Managed Agents platform provides the logging properties required for forensic traceability of agent actions: that logs are complete, that they cannot be tampered with, and that each event can be attributed to the agent that produced it.

Metrics

Log Completeness

Checks whether every category of agent activity is captured in the session event history, including model responses, tool invocations and their results, policy decisions, and inter-agent messages.

Log Immutability

Checks whether individual session events can be modified or selectively deleted after they are written.

Log Attribution

Checks whether each event in a multiagent session can be traced back to the specific agent that produced it.

Motivation

Audit logs are only useful if they are complete, tamper-proof, and attributable. A log missing categories of events leaves gaps an attacker or a malfunctioning agent could exploit without leaving a trace. A log that can be selectively edited or deleted provides no assurance that the record matches what actually happened. And in a multiagent system, a log that does not identify which agent performed each action makes it impossible to investigate failures or policy violations after the fact.

Methodology

All three metrics are static checks derived from the Claude Managed Agents API documentation. They require no account access and return the same result for every deployment.

1. Log completeness - verified from the documented event type catalogue, which covers model responses (agent.message), tool calls and results (agent.tool_use, agent.tool_result, agent.mcp_tool_use, agent.mcp_tool_result), inter-agent messages (agent.thread_message_sent, agent.thread_message_received), and confirmation decisions (session.status_idle with requires_action, user.tool_confirmation).

2. Log immutability - verified from the API reference, which exposes no per-event modification or deletion endpoint. The only deletion operation available is DELETE /v1/sessions/{session_id}, which removes an entire session. Note that this means a session's complete history can be erased; operators who need long-term audit retention must export events before deletion or use archiving instead.

3. Log attribution - verified from the documented event schemas, which carry session_thread_id and agent_name on thread lifecycle events, from_agent_name and from_session_thread_id on inter-agent message events, and session_thread_id on cross-posted tool use events.

Scoring

Log Completeness

Log Immutability

Log Attribution