What belongs in a real failure taxonomy for coding-agent runs?

[Keesan12]

Most agent runs do not fail in one generic way. The useful split we keep seeing is more like:

• budget exhaustion versus budget stop with a useful receipt
• verifier stalled versus verifier improved but blocked on approval
• tool success versus task success
• unsafe side effect blocked versus harmless retryable error
• context drift versus adapter or secret boundary mismatch

If you are building or operating coding agents, what buckets actually matter in practice?

I am trying to make MartinLoop more useful as an open-source control layer here, so I care more about the taxonomy being operationally honest than theoretically neat. If you have a better split, edge case, or field you would want captured in the stop receipt, I would really like to see it.