Returns full metadata for each available worker action. Use this to discover the dynamic payload and result shapes: each action's samplePayload (example request JSON), typesDefinitions (TypeScript interfaces for request/response), and filterType (which filter criteria shape applies). Refer to this endpoint when building or validating execution payloads and when interpreting execution results.

Security: Requires Platform Admin or Project Admin privileges. For Project Admin, the projectKey query parameter is required.