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Structured Output

Force the agent to respond with JSON matching a specific schema.

Overview

Structured output constrains the agent's responses to match a predefined JSON schema. This is useful for building agents that need to produce machine-readable output for downstream processing, API responses, or integration with other systems.

When to Use

Building API endpoints that need consistent JSON responses
Data extraction and transformation pipelines
Agents that feed into other automated systems
Ensuring predictable output format for parsing

Configuration

agents:
  analyzer:
    model: openai/gpt-4o
    description: Code analyzer that outputs structured results
    instruction: |
      Analyze the provided code and identify issues.
      Return your findings in the structured format.
    structured_output:
      name: analysis_result
      description: Code analysis findings
      strict: true
      schema:
        type: object
        properties:
          issues:
            type: array
            items:
              type: object
              properties:
                severity:
                  type: string
                  enum: ["error", "warning", "info"]
                line:
                  type: integer
                message:
                  type: string
              required: ["severity", "line", "message"]
          summary:
            type: string
        required: ["issues", "summary"]

Properties

Property	Type	Required	Description
`name`	string	✓	Name identifier for the output schema
`description`	string	✗	Description of what the output represents
`strict`	boolean	✗	Enforce strict schema validation (default: `false`)
`schema`	object	✓	JSON Schema defining the output structure

Schema Format

The schema follows JSON Schema specification. Common schema types:

Simple Object

schema:
  type: object
  properties:
    name:
      type: string
    count:
      type: integer
    active:
      type: boolean
  required: ["name", "count"]

Array of Objects

schema:
  type: object
  properties:
    items:
      type: array
      items:
        type: object
        properties:
          id:
            type: string
          value:
            type: number
        required: ["id", "value"]
  required: ["items"]

Enum Values

schema:
  type: object
  properties:
    status:
      type: string
      enum: ["pending", "approved", "rejected"]
    priority:
      type: string
      enum: ["low", "medium", "high", "critical"]
  required: ["status"]

Strict Mode

When strict: true, the model is constrained to only produce output that exactly matches the schema. This provides stronger guarantees but may limit the model's flexibility.

strict: false (default) — model aims to match the schema but may include additional fields or slight variations.
strict: true — model output is constrained to exactly match the schema. Stronger guarantees.

Provider Support

Structured output support varies by provider:

Provider	Support	Notes
OpenAI	✓ Full	Native JSON mode with schema validation
Anthropic	✓ Full	Tool-based structured output
Google Gemini	✓ Full	Native JSON mode
AWS Bedrock	✓ Partial	Depends on underlying model
DMR	⚠️ Limited	Depends on model capabilities

Example: Data Extraction Agent

agents:
  extractor:
    model: openai/gpt-4o
    description: Extract structured data from text
    instruction: |
      Extract contact information from the provided text.
      Return all found contacts in the structured format.
    structured_output:
      name: contacts
      description: Extracted contact information
      strict: true
      schema:
        type: object
        properties:
          contacts:
            type: array
            items:
              type: object
              properties:
                name:
                  type: string
                  description: Full name of the contact
                email:
                  type: string
                  description: Email address
                phone:
                  type: string
                  description: Phone number
                company:
                  type: string
                  description: Company or organization
              required: ["name"]
          total_found:
            type: integer
            description: Total number of contacts found
        required: ["contacts", "total_found"]

Example: Classification Agent

agents:
  classifier:
    model: anthropic/claude-sonnet-4-5
    description: Classify support tickets
    instruction: |
      Classify the support ticket into the appropriate category
      and priority level based on its content.
    structured_output:
      name: ticket_classification
      strict: true
      schema:
        type: object
        properties:
          category:
            type: string
            enum:
              ["billing", "technical", "account", "feature_request", "other"]
          priority:
            type: string
            enum: ["low", "medium", "high", "urgent"]
          confidence:
            type: number
            minimum: 0
            maximum: 1
            description: Confidence score between 0 and 1
          reasoning:
            type: string
            description: Brief explanation for the classification
        required: ["category", "priority", "confidence"]

Tool Limitations

When using structured output, the agent typically cannot use tools since its response format is constrained to the schema. Design your agent workflow accordingly — structured output agents work best for single-turn analysis or extraction tasks.

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