Skill

Execution since 1.0 aow:Skill

A reusable capability that an Actor can invoke.

Describes a capability's inputs, outputs, cost, and side effects, so it can be discovered, governed, and replaced.

Attributes

Attribute	Type	Description
`input_schema`	json	JSON Schema (or equivalent) for the Skill's inputs.
`output_schema`	json	JSON Schema (or equivalent) for the Skill's outputs.
`binding`	string	How to invoke it, for example an MCP tool name, an API endpoint, or a UI automation.
`side_effects`	one of `none`, `reversible`, `irreversible`	Whether invoking the Skill changes external state, and whether that can be undone.
`latency`	string	Typical or maximum latency, for example "< 1s".
`cost_profile`	one of `low`, `medium`, `high`	Relative cost per invocation.

Every entity also has an id and a type, and may carry label, description, and the provenance facet: version, created_at, created_by, revision_of.

Relationships

Relationship	Points to	How many	Required	Meaning
`constrained_by`	Policy	many		Policies that apply.
`requires_assurance`	Assurance Level	one		The highest Assurance Level at which this work may be done. The effective level is the lowest of the Intent's, the Task's, the Skill's, and the performing Agent's autonomy_level.

Pointed to by

From	Relationship	Read backward as
Actor	`has_skill`	available to
Action	`invokes`	invoked by
Feedback	`updates`	updated by
Guardian	`oversees`	overseen by

Notes

side_effects is new in 2.0. It records whether a Skill changes external state and whether the change can be reversed. Assurance Levels AL3 and AL4 do not permit irreversible Skills without approval.

Alignments

Standard or protocol	Term	Correspondence
Model Context Protocol	`tool`	closeMatch
Agent2Agent (A2A)	`AgentSkill`	closeMatch
SOA-to-Agentic mapping	`Agentic Tools (from Operation / Common Services)`	relatedMatch

Example

Source: examples/claims-processing.jsonld. The example passes all validation checks.

{
  "id": "skill-extract-claim-fields",
  "type": "Skill",
  "label": "extract_claim_fields",
  "binding": "mcp://claims-tools/extract_claim_fields",
  "side_effects": "none",
  "input_schema": {
    "type": "object",
    "properties": {
      "document_uri": {
        "type": "string"
      }
    }
  },
  "output_schema": {
    "type": "object",
    "properties": {
      "claim_amount": {
        "type": "number"
      },
      "claimant_age": {
        "type": "integer"
      }
    }
  },
  "latency": "< 5s",
  "cost_profile": "medium"
}

Term reference · JSON Schema · SHACL shape aowsh:SkillShape