Question

You are building a weather assistant. Claude calls your get_forecast tool, but the underlying weather API returns successfully with an empty result set because the requested city was not found in its database. The API itself did not throw an error — it simply returned no matching data. How should you handle this in the tool_result you send back to Claude?

Accepted Answer

Return a tool_result with is_error set to true and a message explaining that no forecast data was found for the given city, so Claude can inform the user or ask for clarification.

Answer

Omit the tool_result entirely and let Claude retry the tool call automatically until data is returned.

Answer

Return a successful tool_result containing an empty string, since the API technically succeeded and did not raise an exception.

Answer

Stop the conversation loop and return a generic error message directly to the end user without sending anything back to Claude.