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AnthropicStructuredOutput

Adapts Effect Schema codecs to the JSON Schema subset accepted by Anthropic structured output.

The main entry point returns the JSON Schema to send to Anthropic and a codec for decoding the model response back into the original application type. Unsupported constraints can be omitted from the provider schema and remain enforced by the returned codec.

1 exports Added in v4.0.0 Source

Transforming

toCodecAnthropic

Added in v4.0.0 Source

Converts a Schema.Codec to Anthropic structured-output JSON Schema and a matching codec for model output.

When to use

Use when you send Effect Schema-backed structured output requests to Anthropic and need provider-compatible JSON Schema without losing the decoded application type.

Details

Returns the JSON Schema to include in the request and the codec to use when decoding the model response. The codec remains authoritative: the provider JSON Schema can be a lossy, less restrictive representation when Anthropic cannot express an Effect Schema constraint.

Gotchas

- Some schemas use a provider-safe encoded shape: tuples become objects with numeric string keys, objects with index signatures become arrays of [key, value] pairs, and optional properties become required nullable properties. - oneOf unions are emitted as anyOf unions. - Unsupported constraints are removed from the provider schema and are still checked while decoding with the returned codec. - Recursive schemas throw during conversion because Anthropic structured output does not support recursive references.

See

Signature

declare function toCodecAnthropic<T, E, RD, RE>(
  schema: ConstraintCodec<T, E, RD, RE>,
): {
  readonly codec: ConstraintCodec<T, unknown, RD, RE>;
  readonly jsonSchema: JsonSchema;
};