Bug: MCP closes connection after one request

[Gyurmatag]

In the commented out code, we make a request for the MCP and it finishes we are calling:
await this.mcp.closeConnection(mcpConnection.id);
So the connection is closed and the second request for an MCP tool fails with this:

error: ToolExecutionError [AI_ToolExecutionError]: Error executing tool XIWj-FhT_browser_navigate: Not connected

What about calling it in the destroy() function on the agent? The agent will live in the durable object so I don't think we need to close the connection until the agent is destroyes. I will make a PR about it and we can discuss this in that, @threepointone !

[threepointone]

we can't keep it open, because that will keep the durable object open. .destroy() is not called automatically, it has to be called manually to clean up an agent.

the thing to do is to fix the initialisation properly. I'll look into it.

[Gyurmatag]

@threepointone I see. Maybe we can add a method to the AIChatAgent class that is called something like a "cleanup", which will close mcp connections and other stuff if necessary. Something like this:
cleanUp(): Promise<void>;

and we can implement it in the individual agents that extend the AIChatAgent class like this:

  async cleanup() {
    for (const [serverUrl, connection] of this.mcpConnections.entries()) {
      try {
        await this.mcp.closeConnection(connection.id);
        this.mcpConnections.delete(serverUrl);
      } catch (error) {
        console.error(`Error closing connection to ${serverUrl}:`, error);
      }
    }

And we can call it for example when the component unmounts in the React client side.

[threepointone]

that doesn't solve this problem, if they go back to the page and try to make a call, by your report it'll still fail right?

[Gyurmatag]

@threepointone It just solves the cleanup problem. We should make the opposite when the component mounts, we should make and call something like a "connectToMCPServers" function, which will connect to the MCP servers. We can even make a nice UI for connected MCP servers' status somewhere in the chat like in Cursor or Claude Desktop. What do you think about this?
Btw we should make a reference MCP server to use in the starter. Just the one you made for the MCP Demo day.

[Gyurmatag]

@threepointone I correct myself a little. So right now on every seperate chat message we are making a new MCP connection. Which is not ideal imo. I've looked intoTHIS PR from the agents-sdk, and this will solve most part of the problem, so we can wait for it to get merged.