AI Agent Crash at 261K Tokens Reveals Critical Context Management Gaps

An AI agent research task ballooned to 261,834 tokens, causing it to fail against a 128,000-token model limit. The context grew gradually as replayed tool results accumulated across multiple checkpoints rather than in a single prompt. A post-incident review, logged as INC-002, identified three missing safeguards: no hard token budget, no message cap, and no pruning policy for outdated tool observations. Large search and file outputs were also fed into the model without any compression. Engineers now recommend setting strict token budgets per graph node, capping replayable tool results, compressing observations before model re-entry, and stress-testing with 50 or more simulated tool calls.