> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-5e9cc07a-preview-export-1767976498-81c8aa9.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Updating MCP servers

<Warning>
  Changing the URL of a custom MCP server will break any agents that use tools from that server.
</Warning>

Agent Builder stores tool references by MCP server URL. If you update the URL of a custom MCP server, existing agents will fail when attempting to call those tools because the stored URL no longer matches.

## How to update an MCP server URL

1. Update your MCP server URL in the workspace settings
2. For each agent using tools from that server:
   * Remove the affected tools from the agent configuration
   * Re-add the tools (they will now reference the new URL)
3. Test the agent to confirm tools work correctly

***

<Callout icon="pen-to-square" iconType="regular">
  [Edit this page on GitHub](https://github.com/langchain-ai/docs/edit/main/src/langsmith/agent-builder-update-mcp-servers.mdx) or [file an issue](https://github.com/langchain-ai/docs/issues/new/choose).
</Callout>

<Tip icon="terminal" iconType="regular">
  [Connect these docs](/use-these-docs) to Claude, VSCode, and more via MCP for real-time answers.
</Tip>