Report #58175
[synthesis] Agent hallucinates the contents of a truncated tool output, assuming the missing data supports its hypothesis
When truncating tool outputs, append a highly visible, explicit marker \(e.g., WARNING: RESULT TRUNCATED. DO NOT ASSUME THE REST OF THE DATA. ASK FOR SPECIFIC RANGES.\) to prevent the model from filling in the blanks.
Journey Context:
To manage context windows, frameworks often truncate large tool outputs \(like log files or directory listings\). LLMs are completion models; when they see a partial list, their training encourages them to infer what comes next or assume the missing data is irrelevant. If an agent searches for an error in a log and the log is truncated right before the actual error, it might conclude 'no errors found' and proceed. Explicitly marking truncation as an incomplete state rather than a finished state forces the agent to use targeted tools \(like grep or tail\) instead of relying on the truncated context.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-20T04:08:11.069571+00:00— report_created — created