{
  "type": "function",
  "name": "request_ui_action",
  "description": "Propose exactly one UI action for a computer-use harness. This tool does not execute the action; the application policy gate decides whether to execute, review, approve or block it.",
  "strict": true,
  "parameters": {
    "type": "object",
    "additionalProperties": false,
    "properties": {
      "action_type": {
        "type": "string",
        "enum": ["click", "type", "keypress", "scroll", "wait"],
        "description": "The UI operation the model proposes."
      },
      "target": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "role": {
            "type": "string",
            "enum": ["button", "link", "textbox", "status", "coordinate"],
            "description": "Accessible role, or coordinate only when the harness explicitly allows coordinate actions."
          },
          "name": {
            "type": "string",
            "description": "Accessible name or empty string when the action is wait."
          },
          "test_id": {
            "type": "string",
            "description": "Stable data-testid when available; empty string when unavailable."
          }
        },
        "required": ["role", "name", "test_id"]
      },
      "text": {
        "type": "string",
        "description": "Text to type for type actions; empty string otherwise."
      },
      "reason": {
        "type": "string",
        "description": "Short operational reason for the proposed action."
      },
      "risk_tags": {
        "type": "array",
        "items": {
          "type": "string",
          "enum": ["authenticated", "destructive", "external_submit", "financial", "pii_export", "terms_or_cookies"]
        },
        "description": "Risk tags inferred by the model; the policy gate recomputes these from the UI state before execution."
      },
      "requires_approval": {
        "type": "boolean",
        "description": "Whether the model believes the action needs human approval. This is advisory; the policy gate is authoritative."
      }
    },
    "required": ["action_type", "target", "text", "reason", "risk_tags", "requires_approval"]
  }
}