You are building a structured data extraction system using Claude.

An unchanged retry repeats the same task specification and therefore commonly reproduces the same invalid interpretation. The validator has generated precise corrective information— quantity requires a float, but the model returned the range string 2 to 3 . Supplying that error in a follow-up turn converts a generic retry into an iterative repair operation.

Anthropic identifies iterative refinement as a method for detecting and correcting inconsistencies by feeding an earlier output back into a subsequent request with targeted instructions. ( https://docs.anthropic.com/en/docs/test-and-evaluate/strengthen-guardrails/reduce-hallucinations ) Option A applies that pattern directly. Claude receives the invalid output, the exact Pydantic error, and an instruction to return a schema-compliant correction. The application should cap retries, retain the original source, and escalate cases that cannot be represented without information loss.

Option B does not guarantee correct formatting; lower temperature may make the same wrong output more repeatable. Option C can be valuable for systematic OCR or source-format problems, but it is unnecessarily broad when the immediate failure is already described by the validator. Option D increases cost and complexity without first using the actionable feedback available from the existing validation layer.

For supported models, native Structured Outputs should also be considered because they guarantee schema-conformant JSON and can prevent many Pydantic shape failures before they occur. ( https://platform.claude.com/docs/en/build-with-claude/structured-outputs )

Official references/topics: Iterative Refinement; Validation-Error Feedback; Bounded Retry Loops; Structured Outputs.