You are building a structured data extraction system using Claude.

The most reliable architecture separates semantic interpretation from deterministic normalization. Claude is well suited to identifying that “$12” and “12.00” represent prices, or that a leaf icon represents a dietary classification. However, canonical conversion—removing currency symbols, converting values to decimal types, mapping icons to controlled labels, and enforcing locale-specific rules—is more predictably performed in application code.

Structured Outputs guarantee that Claude returns valid JSON matching the supplied schema, but that guarantee concerns structural conformance. It does not by itself guarantee that every semantically equivalent source representation will be normalized identically. Anthropic’s evaluation guidance identifies code-based checks as the fastest, most reliable, and most scalable mechanism for rule-based validation. ( https://platform.claude.com/docs/en/build-with-claude/structured-outputs )

Option D therefore minimizes model responsibility: Claude extracts the evidence as represented, and deterministic post-processing converts it into the canonical downstream format. This also makes normalization rules independently testable, version-controlled, and auditable.

Option A increases latency and cost without solving normalization. Option B improves output structure, but prompt-based normalization can still vary across ambiguous formats. Option C introduces unnecessary stochasticity and majority-vote logic where explicit parsing rules are available. The downstream contract should remain stable, but format conversion should be implemented using deterministic transformations rather than repeated probabilistic inference.

Official references/topics: Structured Outputs—schema compliance; Evaluation Design—code-based validation; Reliable extraction pipelines.