Structured Output

Structured output ensures model responses conform to a JSON schema before returning to your application. Eridian validates output at the gateway so downstream systems receive typed, parse-safe payloads without custom post-processing in every service.

Configuration

Add structured_output to any inference request:

{
  "model": "auto",
  "project_id": "prj_legal_001",
  "messages": [
    { "role": "user", "content": "Extract risks from this contract clause." }
  ],
  "structured_output": {
    "schema": {
      "type": "object",
      "properties": {
        "risks": {
          "type": "array",
          "items": { "type": "string" }
        },
        "severity": { "type": "string", "enum": ["low", "medium", "high"] }
      },
      "required": ["risks", "severity"],
      "additionalProperties": false
    },
    "retry_on_failure": true,
    "max_retries": 2
  }
}

Fields

Retry on Parse Failure

When retry_on_failure is enabled, Eridian re-invokes the model with parse error feedback if the response fails schema validation. Each retry is logged as a separate span in OpenTelemetry traces. Responses include:

• eridian.structured_output_valid - true when final payload passed validation
• eridian.structured_output_retries - count of retry attempts

Response Shape

Validated structured output appears in choices[0].message.content as a JSON string and in choices[0].message.parsed as a native object when using official SDKs:

{
  "choices": [{
    "message": {
      "role": "assistant",
      "content": "{\"risks\":[\"Indemnification cap missing\"],\"severity\":\"high\"}",
      "parsed": {
        "risks": ["Indemnification cap missing"],
        "severity": "high"
      }
    }
  }],
  "eridian": {
    "structured_output_valid": true,
    "structured_output_retries": 0
  }
}

Custom Parsers

Enterprise customers can register custom parsers for domain-specific output formats (FIX messages, SWIFT MT fields, internal JSON dialects). Custom parsers run after default JSON schema validation:

POST /v1/parsers
Authorization: Bearer eridian_sk_...

Parser registration requires governance:manage scope. Parser IDs attach to templates for repeatable workflows.

Caching Interaction

Structured output requests are excluded from semantic cache by default because near-identical prompts may require different schema shapes. Opt in with cache_config.allow_structured_output: true only when schemas are stable and false-positive cache hits are acceptable.

Error Codes

See Inference for the core request envelope and Semantic Caching for cache exclusion rules.