Windmill is an open-source platform for building internal tools, scripts, flows, and workflows that run on a managed worker infrastructure.
Agen.co connects to Windmill through Windmill's own hosted MCP gateway as an Official connector. Each user signs in with their own Windmill account and chooses which of their workspace's scripts and flows agents can call, so there is no app to register and no credentials to copy.
Prerequisites
Prerequisites
- A Windmill account on Windmill Cloud (
app.windmill.dev). The connector points at the Windmill Cloud gateway,https://app.windmill.dev/api/mcp/gateway; it has no field for a self-hosted Windmill instance URL. - Access to the Windmill workspace whose scripts and flows you want agents to use.
Windmill registers Agen.co automatically, so there is no client ID or secret to copy and no callback URL to register.
In the Agen.co portal, go to Connectors → My connectors and click Add connector.
In the Select connector drawer, search for
Windmilland select it. The Add Windmill panel opens.Fill in the field:
Field Required Description Instance Slug Yes Namespaces this instance — it prefixes each imported tool as slug__tool, so several instances of the same MCP can coexist. Prefilled withwindmill. Use lowercase kebab-case. You can change it later from the connector's settings.Click Connect. Windmill opens in a new tab, and the panel shows Waiting for authorization — complete it in the opened tab…
Sign in to Windmill. Windmill then asks you to select your workspace and choose which tools to expose, and to approve access.
Back in Agen.co, the panel switches to Select the tools to import from Windmill. Every tool is toggled on; turn off any you don't want to import, then click Add.
The connector is created and its tools imported only when you click Add. If you close the panel before that, nothing is saved, even if the Windmill tab reported success.
Each connector instance is authorized for the workspace you choose during the Windmill sign-in. To give agents a second workspace, add the Windmill connector again with a different Instance Slug and choose the other workspace.
Windmill exposes your workspace's scripts and flows as individual tools, plus built-in tools for managing the workspace:
| Area | What it covers |
|---|---|
| Scripts and flows | Each script and flow you expose becomes a tool that agents can run |
| Jobs | Monitor jobs, logs, and status |
| Resources and variables | Manage resources, variables, and secrets |
| Schedules | Create and update schedules |
| Workers | Check worker status |
| Apps and data | Work with apps and data operations |
At sign-in you can limit what is exposed to all tools, favorites only, or selected folders. Agen.co asks for Windmill's mcp:all, mcp:favorites, mcp:scripts:*, mcp:flows:*, and mcp:endpoints:* scopes. The list follows Windmill's MCP documentation (checked 2026-10-06) and can change with your workspace's contents.
Enabling the Windmill connector isn't enough on its own. Tool calls remain denied until you create a policy that grants access to the specific tools you want to expose.