artifacts/<name>.yaml

An artifact is a typed structured value passed between phases. Each artifact has a YAML schema in the skill's artifacts/ directory.

Minimal example

# artifacts/topic_input.yaml
type: object
required: [topic]
properties:
  topic:
    type: string
    description: Subject the skill should write about.

Schema

reyn artifact files are JSON Schema (Draft-7) fragments expressed in YAML.

Field	Required	Notes
type	yes	Almost always object.
required	optional	List of required property names.
properties	yes (for objects)	Map of name → JSON Schema.
description	optional	Free-form description; surfaces in the LLM context.
additionalProperties	optional	Default: true. Set false for strict shapes.

Strict vs lenient validation

By default, reyn validates only the top level — nested required fields are not enforced. Pass --strict to enforce required fields at every nesting depth.

Cross-skill artifacts (stdlib)

Artifacts under src/reyn/stdlib/artifacts/*.yaml are available to every skill. The most common is user_message:

# src/reyn/stdlib/artifacts/user_message.yaml
type: object
required: [text]
properties:
  text:
    type: string
    description: Free-text user input.

Skills that accept natural-language input declare input: user_message | <other_artifact> in their entry phase.

Naming conventions

• Files: lowercase_snake_case.yaml.
• Type: filename without .yaml is the artifact's type name.
• Properties: lowercase_snake_case.
• Avoid kitchen-sink artifacts; if a property is needed only for one phase, put it in that phase's input artifact.

Validation in the runtime

• On transition: the LLM's artifact.data is validated against the next phase's input schema.
• On finish: validated against the skill's final_output_schema.
• Failures emit validation_error events and re-prompt (subject to retry limits).

See also

• skill-md.md — final_output references an artifact name
• phase-md.md — phase input references one or more artifact names
• graph.md — graph + artifact resolution