Skip to main content
If the Gumloop MCP server connects successfully but tool calls fail, the issue is usually related to your setup, permissions, or server configuration. This guide covers the most common causes and fixes across Claude, Claude Code, Cursor, ChatGPT, and other MCP clients. It focuses on the Gumloop MCP server at https://mcp.gumloop.com/gumloop/mcp, which provides access to your agents, sessions, and skills. For initial setup, see MCP server.

​
Which error do you have?

​
Generate a Gumloop API Key

The Gumloop server needs a Gumloop API Key connector on your account. Signing in from your client links the connection to that key, so without one every account tool fails, even though the sign-in itself succeeded.
1

Open Connectors

Go to Connectors.
2

Add the Gumloop API Key connector

Click Add Connector and search for Gumloop API Key.
3

Generate the key

Click Generate API Key. You do not need to copy it into your client. The client’s sign-in finds it for you.
4

Sign in again from your client

Remove the Gumloop server from your client, add it again, and complete the sign-in. Pick Personal on the authorize screen.
To generate or rotate the key later, see Find your Gumloop API key.

​
Pick the right team when you sign in

The Team dropdown on the authorize screen chooses which Gumloop API Key the connection uses, not which agents you can see. Pick the space where your Gumloop API Key lives. For most people that is Personal.
  • Personal works with your personal key. It still reaches agents in every team you belong to. Name the team in your prompt, for example: “List the agents in my Marketing team.”
  • A team works only if someone generated a Gumloop API Key on that team’s Connectors page. A team key sees that team’s agents only, not your personal agents or other teams. Use a team when the connection should act as the team rather than as you, such as a shared service connection.
Gumloop authorize screen with the Team dropdown set to Personal

Pick Personal unless your team has its own Gumloop API Key.

For a team that uses Claude, have each person connect with their own personal Gumloop API Key. One connection covers their personal and team agents, and every action stays attributed to the person who ran it.
Some tools do not accept a team Gumloop API Key. create_session, for example, does not work with a team key. If you signed in with a team key and a tool returns 403, sign in again with Personal and your personal key.

​
If every call returns 403, ask an admin to unblock the server

A 403 on every tool, including the documentation tools, means your custom role has the Gumloop server turned off. This is a permission setting, so removing and re-adding the server in your client does not change it. An organization admin fixes it:
1

Open the custom role

Go to Organization → Roles and open the custom role the user belongs to. Custom roles add up, so check every role the user is in.
2

Re-enable the Gumloop server

On the role’s Connectors tab, find the Gumloop server and allow it for the role.
The user can retry right after the admin saves. They do not need to sign in again. For how roles work, see Custom roles.

​
Use the right server URL

The Gumloop server URL is https://mcp.gumloop.com/gumloop/mcp. The Gumloop connectors directory has a ready-made URL or command for Claude, Claude Code, Cursor, Codex, and ChatGPT.
These URLs do not work as MCP servers: https://mcp.gumloop.com/mcp (no service name) and https://www.gumloop.com/mcp/... (that is a web page). If you added either one, Gumloop or your client loads a web page instead of MCP tools, so it shows zero tools or an auth error. Remove it and add the server again with the URL above.

​
Reset a stuck connection

If the client says “Could not attach to MCP server” or “Authentication successful, but server reconnection failed,” it is usually holding an old sign-in. Clear it and connect again.
Use the server name you gave it if it was not gumloop. Restart Claude Code, run /mcp, select the server, and sign in.
If the reset does not help, check whether a company firewall or VPN blocks mcp.gumloop.com.

​
FAQ

No. It works on all accounts with an active subscription, trial included. You just need a Gumloop API Key, which you generate from the Connectors page.
Reconnecting only redoes the sign-in. It does not change what the connection is allowed to do. A 403 that survives a reconnect is almost always a custom role that blocks the Gumloop server, or a sign-in that used a team with no Gumloop API Key. Ask an admin to check the role’s connector access, and sign in with Personal.
Gumloop MCP shows personal agents unless you name a team. Ask your client to list your teams first, then ask for the agents in a specific team. You can reach any team you are a member of.
Yes, with a team Gumloop API Key on the team’s Connectors page, then pick that team when you sign in. The tradeoff: the connection sees only that team’s agents, and actions are not attributed to individual people.
Check the server URL. It must be https://mcp.gumloop.com/gumloop/mcp. The web page address https://www.gumloop.com/mcp/gumloop returns a page, not MCP tools. Remove the connector from the agent, delete the server, and add it again with the right URL.

MCP server

Set up Gumloop MCP in your client

Find your Gumloop API key

Generate or rotate the key