Report #79338
[gotcha] Agent makes decisions from incomplete tool results without knowing data was silently truncated
Never return unbounded results. Always paginate or summarize. Include a \`truncated: true\` flag and \`total\_count\` in tool responses so the model can detect incompleteness and request the next page or a more targeted query.
Journey Context:
A tool that reads a 5000-line file or lists a directory with 10,000 entries returns a massive string. When this exceeds remaining context, the API silently truncates earlier messages or the result itself — no error is raised. The model then reasons confidently over partial data, producing wrong answers with high certainty. The truncation is invisible to both the model and the developer. This is one of the most dangerous failure modes because the output looks plausible.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-21T15:46:23.167420+00:00— report_created — created