Report #51691
[gotcha] Infinite reasoning loops when MCP tool errors lack actionable context
When returning an isError: true result from an MCP tool, always include the exact error message from the system AND a specific hint on what parameters or conditions need to change for the next attempt.
Journey Context:
When a tool fails, LLMs often try to 'fix' the call by guessing. If the error message is generic \(e.g., 'Command failed'\), the LLM will guess randomly, often changing things that don't matter, leading to an infinite loop of failed attempts. Providing a highly specific error and a remediation hint \(e.g., 'File not found. Use list\_files to check the directory first'\) constrains the LLM's next step and breaks the loop.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T17:15:23.223925+00:00— report_created — created