When a coding agent fails, the visible error is rarely the whole story. You might see: a tool call that never ran a command repeated again and again a sudden token spike a provider rejecting a request with 400 Bad Request an agent that says it edited a file but did not a long session that starts producing shallow or confused answers The usual reaction is to tweak the prompt and try again. Sometimes that works. But for agentic coding tools, guessing is not enough. You need to inspect what the age