Output Formats

| `output_format` value | Behavior |

v0.4.0concept

Output formats (v0.2)

`output_format` value	Behavior
(omitted)	Free text. Executor doesn’t validate.
`text`	Same as omitted; declared for documentation only.
`structured_json`	Post-LLM `JSON.parse` + assert `fields` exists. Fail-fast on missing fields.
`code`	Treated as text; declared for documentation. Future (v0.3) will lint + syntax check.
`markdown`	Treated as text; future (v0.3) will validate fences.
`zip` (output.only)	Output is a multi-file archive delivered via signed URL. Stage-level `output_format` does NOT support zip; use the pipeline-level `output` field.

If output_format: structured_json is declared, the stage executor MUST validate all fields in fields: [...] exist in the LLM output. Missing required field → StageOutputFormatError, abort pipeline, refund buyer.

Example:

- id: research
  model: gpt-4o
  prompt: |
    Topic: $input.topic
    Return JSON: { "summary": str, "key_points": [str], "sources": [str] }
  output_format: structured_json
  fields: [summary, key_points, sources]