Why Every MCP Agent Needs an Independent Observer

There is a sentence I keep coming back to. I first saw it from @aginaut on X: "If the agent controls the logs, the logs are fiction." That line stuck because it names a problem I had been circling for months while building agent infrastructure. The problem is not that agents are malicious. The problem is that self-reported behavior is structurally untrustworthy, and most agent deployments treat it as ground truth anyway. The Self-Reporting Problem When an agent logs its own behavior, the logging is downstream of the agent's own reasoning. The agent decides what to record, when to record it, and what to omit. This is true even when the agent is "trying" to be accurate. LLMs summarize. They compress. They confabulate. These are features of the architecture, not bugs in a particular model. Consider a concrete scenario. You have a support agent that retrieves docs, synthesizes an answer, and logs its execution. The agent reports: retrieved 3 documents, generated a response, latency 1.2 sec