---
title: MCP servers
description: Give your agents extra tools, such as your issue tracker or error monitoring, with MCP servers.
---

MCP servers give agents tools beyond your code: search and update issues, read
your team's docs, look up errors while debugging. Add a server once in
Settings, and every Codex and Claude Code Session it reaches can use it.

![The MCP servers list showing remote and command servers, who each is available to, and their status, including one that needs Reconnect and one not yet connected.](/docs/screenshots/mcp-servers.webp)

## Add a popular server

1. Open **Settings → MCP servers** and select **Discover**.
2. Under **Popular**, select **Linear**, **Notion** or **Sentry**.
3. Choose who gets it in **Available to**, then select **Continue** and sign
   in.

## Add any other server

![The Add custom server dialog with the name notion, the server URL https://mcp.notion.com/mcp, Available to Everyone in the Organization, and Continue.](/docs/screenshots/mcp-servers-add.webp)

1. Select **Add**, then one of:
   - **Add custom server (URL)** for a server on the web. Enter its **MCP server
     URL**.
   - **Add command server** for one that runs on the Machine in each Session.
     Enter its command.
2. Give it a **Name**, choose **Available to**, then select **Continue** or
   **Add server**.

A command server gets the Project's [environment variables](/docs/environment-variables),
so put its keys there, never in the command.

## Sign in

When you add a server on the web, Polaris checks how it signs in:

- **No sign-in needed:** select **Done**.
- **API key:** paste it. Polaris sends it only to that server, and it never
  reaches the Machine.
- **OAuth:** select **Connect my account** to sign in as yourself. On a server
  others get too, **Connect shared account** signs in once for everyone who
  hasn't connected their own.

Once an OAuth server is signed in, the **Status** column shows **as you** or
**shared**. Your own account always wins for your Sessions.

## Choose who gets it

| Available to | Reaches | Who can add it |
| --- | --- | --- |
| **Everyone in the Organization** | Every Session in the organization | Owners and Admins |
| **A Project** | Sessions in that Project | Owners and Admins |
| **Only me, in every Project** | Only your Sessions | Anyone |

Everyone can see the organization's and Projects' servers, except one that an
admin limited to selected people or groups. If a server your team uses is
missing for you, ask an admin to add you to it. If two lists have a
server with the same name, your own wins over a Project's, and a Project's over
the organization's.

To see what agents did with a server on the web, open it: **Recent use** lists
its recent calls and the Sessions that made them.

## When changes apply

New Sessions get the change. A Session that's already running keeps the
servers it started with, except that removing a server on the web, or taking
it away from someone, stops its tools right away. A command server keeps
running in Sessions that already started it, so start a new Session when it
must be gone. After you connect or reconnect a sign-in, open the
server and choose **…** → **Retry in my open Sessions**. Polaris reconnects it
right away in Sessions whose agent supports that, and tells you which Sessions
get it when they next start.

## If it doesn't work

- **Connect** or **Reconnect** in the **Status** column: the sign-in is
  missing or expired. Select it and sign in. If your own sign-in expired,
  **Use shared instead** switches you back to the shared one.
- **This server signs in at** another address: select **Use this address**.
  If it says **This server's sign-in belongs to another website**, Polaris
  won't send your sign-in there; check the server's address with whoever runs
  it.
- **Replaced by** in the **Status** column: another list has a server with the
  same name, and Sessions use that one. Rename one of them.
- **A server's tools are missing in a Session:** start a new Session, or use
  **Retry in my open Sessions**.
- **Only lets approved apps connect:** that service accepts only apps it has
  approved, and Polaris isn't one of them. Ask whoever runs it to approve
  Polaris.
- **Rejected Polaris's request to set up sign-in:** that service didn't accept
  the setup Polaris asked for, so Polaris can't connect to that server.
  [Report a problem](/docs/feedback) and include the server's address.
- **A sign-in message that names the server's administrator:** Polaris can't
  sign in to that server as it's set up. Ask its administrator, as the message
  says.