Action (OpenAI Agents): Definition
An Action is a custom, OpenAPI-defined tool that extends a Workspace Agent's reach to systems without native connectors, including any REST API your team exposes.
Longer definition
Where connectors are the native integrations OpenAI maintains, Actions are the extensibility layer. If a tool isn't in the connector catalog (a niche SaaS, an internal API, a legacy ERP), you can define it as an Action by providing an OpenAPI 3.0+ specification. The agent then calls the Action like any other tool. Actions can also bridge to Zapier, giving agents indirect access to 6,000+ tools without building each individually.
In practice
Actions add setup time (1–3 hours for a simple OpenAPI spec, more for complex ones) but extend Workspace Agents to essentially any system with an API. Most teams start with native connectors and add Actions for the 2–3 tools that aren't covered.
Common mistakes
- Building Actions for tools that already have native connectors, which adds unnecessary complexity
- Under-specifying the OpenAPI spec, since the agent will call the Action wrong if the spec is ambiguous
- Skipping authentication on Actions, when exposing internal APIs to agents requires tokens scoped correctly
See also
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