The Tools Host API retrieves and runs the tools that apps installed on a Wix site expose to AI agents, such as Aria. An app declares its tools in its App Tools extension, each with a description and a JSON Schema for its input, and serves them through the Tools Provider service plugin.
With the Tools Host API, an agent can:
- Retrieve the tools of every installed app on a site, grouped by app, with List Tools Providers.
- Run one of those tools with Invoke Tool. Wix forwards the payload to the app and returns the app's response.
Site owners can switch tools off for their site, per app with Set Tools Providers Toggle or per tool with Set Tools Toggle. A disabled app or tool stays in the list with its settings.enabled set to false, and Invoke Tool rejects it.
A tool is one action. An app can also declare skills, the know-how around its tools: when a job applies, which tools to call in which order, and how to report. Agents retrieve skills with the App Skills API and run the tools a skill names with Invoke Tool.
Wix checks that the app is installed on the site, that it declares an activated tool with the requested methodName, and that the site owner hasn't disabled the app or the tool. Wix doesn't validate the payload against the tool's requestSchema, and doesn't validate the app's response against its responseSchema. Build the payload from the schema returned by List Tools Providers, and treat the response schema as the app's own declaration.
It’s important to note the following points before starting to code:
- The site is determined by the call's identity, not by a parameter. Call the API with an identity that is bound to the site: an app instance token of an app installed on the site, or an API key together with the
wix-site-id header. For details, see About Identities.
- An app appears in List Tools Providers only when it's installed on the site, has a Tools Provider extension, and declares at least one activated tool. Up to 30 apps are returned.
- The two toggle methods are for site owners. Call them with the site owner's identity, for example from the site's dashboard or through the Wix MCP; calls made with an app's identity or an API key are rejected with a permission error.
- A tool's effects are the app's. A tool whose description says it sends, creates, updates or deletes something does exactly that when invoked; confirm such actions with the user before running them.
- Tools provider: an app installed on the site that exposes tools. Identified by its app ID, which is the
providerAppId in the other methods.
- Tool: one action or lookup an app exposes, identified by its
methodName within the app.
- Request schema: the JSON Schema of the tool's payload, declared by the app.
- Response schema: the JSON Schema of the tool's response, declared by the app and not enforced by Wix.
- Settings: the site's enable or disable state for an app's tools as a whole, and for each tool. Enabled until the site owner changes it.
- Skill: an app's instructions for a job that uses its tools, served by the App Skills API.