Output contract

Successful command data is JSON on stdout and can be piped to tools such as jq. Its schema is command-specific: direct resource reads preserve provider fields, while list, search, analysis, and version commands may normalize, project, or enrich the result. Command-owned success responses add "ok": true.

vac retell agents list --fields agent_id,agent_name | jq '.items'

Failures write one structured JSON object to stderr and set a nonzero exit status. src/core/cli-response.ts defines the outer shape and the Retell formatter maps provider failures into safe codes.

{
  "ok": false,
  "error": {
    "code": "AUTH_ERROR",
    "message": "Retell authentication failed.",
    "retryable": false,
    "next_steps": [
      "Set RETELL_API_KEY for this process or run `vac retell login`.",
      "Run `vac retell agents list --limit 1` to verify authentication."
    ]
  }
}

Automation should branch on error.code, retry only when retryable is true, and follow next_steps in order. Error messages are redacted and truncated by src/providers/retell/services/output-formatter.ts.

--help and --version intentionally remain human-readable. Treat them as discovery output, not JSON command data.