Doom-loop detection in autonomous agents: Fingerprint and sliding window
Prudent-Amphibian453 · reddit · 2026-07-20
Autonomous agents often get stuck in doom-loops, repeatedly calling the same tool and burning API budgets. A developer shared their detection approach:
- Fingerprinting: Hashing the tool name and arguments to create a unique identifier for identical calls.
- Sliding Window: Keeping a FIFO log of the last 20 fingerprints.
- Cycle Detection: Identifying repeating cycles of length 1 to 3 that occur at least 3 times.
- Escalation: Injecting a gentle nudge on the first detection, a stronger warning on the second, and halting the turn on the third.
The author notes this only catches byte-identical structural loops, missing semantic no-progress loops where args vary slightly. They are looking for community insights on smarter techniques, such as using embeddings for similarity or an LLM-judge to evaluate actual progress.
Related event: Catching Agent Infinite Loops: Fingerprint & Sliding Window(6 posts)→
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