Custom Tools

A Custom Tool is a user-defined HTTP call that an AI agent (or a dedicated node) can invoke. Use custom tools to give agents access to your own APIs and services without writing runtime code.

Defining a custom tool

A custom tool stores a name, description, HTTP method, URL, headers, and an optional body template, plus an enabled flag. Create and manage them in the Custom Tools view or through the custom-tools API.

Templating. Interpolate the agent's input into the URL, headers, and body with placeholders:

• {{input}} — the whole input
• {{input.path.to.field}} — a nested field

Secrets. Reference stored workspace credentials with {{credential.NAME}} (also {{secret.NAME}} / {{secrets.NAME}}). Confluye resolves required secrets before the call and fails fast if an input or secret is missing, so credentials never appear inline in the tool definition.

Testing a tool

Test a tool before using it in production with POST /api/custom-tools/{id}/test (and the v1 equivalent). The test resolves workspace secrets, performs the request with a default 15-second timeout, and returns a structured result with the status, latency, and response body. GET/HEAD requests send no body; other methods send JSON or the rendered body template.

Using tools in agents

Google Workspace REST tools used by agents require HTTPS and a verified agent grant and production approval for its granted scopes, or an exact administrator-configured verification audience. Credential access and execution authority are checked at transport initiation. These requests do not follow redirects or use A2A status polling. Google multipart batch endpoints are unavailable for agent tools because individual subrequests can override authentication. Use separate REST requests instead. JSON API methods such as Docs batchUpdate remain available as a single authenticated request.

The same agent checks apply to ordinary Google Workspace routes, uploads and media downloads on service-specific hosts, including the content-gmail, content-drive, content-docs, content-sheets, content-slides and content-calendar aliases under googleapis.com, and the shared googleapis.com, www.googleapis.com and content.googleapis.com origins. Shared origins use the API route to identify the Workspace service.

Official Google Workspace MCP endpoints must use the registered Google Workspace MCP connection. A custom HTTP tool cannot call those endpoints directly.

There are two ways a custom tool runs:

1. 1

   From an AI agent block

   Add the tool to the agent's customToolIds. The agent can then call it as a tool during its reasoning, with the model deciding when to invoke it.

2. 2

   As a dedicated node

   Use the Custom Tool node and set its customToolId to call the tool directly as a workflow step.

Next steps