All Lessons
A developer implements a validate_address tool that checks shipping addresses against a postal database. Sometimes the postal database is temporarily unavailable, and the tool returns an error. The developer wants Claude to retry the tool call when this happens instead of giving up. They include an isError field in the tool_result. What does the isError field in a tool response mean to Claude?
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intermediate 20 min
Error Handling
Based on Anthropic Claude documentation and the CCA-F exam blueprint. Updated June 2026.
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A tool always returns isError=true for a specific input that should be valid. What's the likely issue?
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A critical workflow tool fails intermittently with 'service unavailable'. The model gives up on the first failure. What's the best pattern?
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