Every tool your servers expose is sent to the model on each request, and the model reads the whole list before picking one. Add a few servers and that list gets long. It costs tokens on every turn, and a page of near-identical names makes the model’s choice less reliable.
MCP Nest lets you hide individual tools from your workspace. Your servers keep running exactly as before and nothing is redeployed. The tool just stops appearing in the list your client asks for.
Disable a tool
- Open your workspace once your servers have been discovered.
- In the Servers & tools panel, pick a server from the list on the left. Its tools appear alongside it.
- Click the toggle next to a tool to turn it off. Disabled tools stay in the list, dimmed, with the toggle switched off.
The change saves immediately.
Clients cache the tool list
MCP Nest filters every tools/list response against your current settings, so a client that asks again gets the updated list straight away. What it does not get is a reason to ask: MCP Nest sends no notifications/tools/list_changed, so nothing tells your client the list it is holding is out of date.
Most clients fetch the list when they connect and keep it for the session, so turn a tool off, switch back to Claude or ChatGPT, and it will usually still offer the tool. If it does, reconnect the MCP server in your client, or restart the client, and the new list arrives.
What the setting covers
Toggles are stored against your MCP Nest account and the tool’s canonical name, not against a config.
Your toggle applies to every config of yours that exposes a tool of that name. Disabling github__create_issue hides it from all of them, not just the config you set it in.
It also applies to every connection authenticated as your account, not just the client you were using. A pre-authenticated URL carries your token, so anyone you hand that URL to gets your toggles along with it. Treat the setting as belonging to the account rather than to one person at one client.
Only the tools you turn off are recorded. Anything you have never touched stays enabled, including tools that show up later when you add a server.
Tool names come from the upstream server and are namespaced as <server>__<tool>, so a github server in your config produces github__create_issue, github__list_pull_requests, and so on. Renaming a server changes those names, and so does an upstream release that renames a tool, which leaves toggles set against the old names matching nothing.
Hiding a tool is not blocking it
Disabling changes what MCP Nest advertises. It does not reject calls.
A client that already knows the name can still call the tool, and MCP Nest will forward that call to your server and hand back the result. In practice this happens with a client holding a tool list from before you made the change, or one configured to call a tool by name directly.
If a tool must never run, take it out of the server’s configuration or remove the credentials it depends on.
Seeing how long the list is
Each server in the left-hand list carries a badge with the number of tools it reported, which is the quickest way to find the server responsible for the bulk of your tool list.
After changing your servers
Refresh tools in the Servers & tools panel re-reads the list from the deployment that is currently running. The button appears once a deployment exists.
Adding or renaming a server edits your configuration without deploying it, so deploy those edits first and refresh afterwards. Refreshing before you deploy just re-reads the old deployment and will not show the change.
Refreshing does not clear your toggles. A tool does come back enabled if its canonical name changed, either because you renamed its server or because the upstream package renamed the tool itself. Turn it off again under the new name.
Troubleshooting
The tool is still offered in my client. The client is holding a cached tool list. Check that the tool still shows as dimmed with its toggle off, then reconnect the MCP server in the client, or restart it.
The workspace shows tools my servers no longer have. Click Refresh tools. If they are still there afterwards, the deployment is probably still serving the old version, so check its status.
A tool I disabled came back on its own. Toggles are keyed on <server>__<tool>, so anything that changes that name leaves the old toggle matching nothing. Renaming the server does it, and so does an upstream release that renames the tool. Turn it off again under the new name.