What are custom tools (MCP servers) in codus?
MCP servers are how you give your agents extra tools, on top of the ones codus already builds in. You find them under the gear (⚙), click See all settings →, then click MCP servers in the list on the left, where the description reads "Add tools your agents can use." The section opens with the line "Give your agents extra tools." Each server you add brings a set of tools your agents can then use while they work for you. Most people never need this, and codus never spells the three letters out, so you do not have to know what they stand for.
Where to find it
- Click the gear (⚙) in codus, then See all settings →.
- In the list on the left, click MCP servers (its description reads "Add tools your agents can use").
- The section opens with this line:
Give your agents extra tools. Each enabled server's tools reach the matching agents live, within seconds of saving, including agents mid-conversation. No restart needed.
What "extra tools" means
Your agents already come with a large set of built-in tools, so for most work you never add anything here. An MCP server is a small tool provider you can plug in when there is a specific capability you want your agents to have that codus does not already include. Once you add one and turn it on, its tools join the ones your agents can already reach, and they can call those tools when you ask.
codus ships two Quick add templates as ready-made starting points, so you can see the kind of thing an MCP server provides:
- Chrome bridge points an agent at your own real Google Chrome.
- Playwright is an automated browser for testing web pages.
These are examples, not a limit. If you have another tool that is published as an MCP server, you can add it the same way.
MCP servers are not the same as Integrations
It is easy to mix these two up, because both extend what your agents can do:
- Integrations (a separate settings section) connect codus to services you already use, such as GitHub, Vercel, or Stripe, each with a Connect button. Start there for a named service. See How do integrations work in codus?.
- MCP servers plug in a separate tool provider that codus does not include out of the box. Reach for this only when there is a specific MCP tool you want to add.
The built-in "codus" server
At the top of the MCP servers section is a row named codus, marked built-in and always on, scoped to All quadrants. This is where your agents' standard codus tools come from. You cannot edit, disable, or remove it, and everything listed below it is yours to manage. The name codus is reserved, so you cannot name one of your own servers that.
How do I know a server is doing anything?
Once a server you added is turned on and reachable, its row shows a live status line. When it is working you see "connected", the number of tools it provides, and "live in all agents", for example "connected, 5 tools, live in all agents". While it is still connecting you see "connecting", and if it cannot connect you see "not connected" with a short reason. That line is your proof the tools actually reached your agents, not only that the row was saved.
Do I need this at all?
Probably not, and that is fine. If you do not have a specific MCP tool in mind, you can leave this section alone. Nothing here is required to use codus. When you are ready to add one, see How do I add a custom tool server (MCP) to codus?.