Failed to connect MCP server

Error message

Failed to connect MCP server '{server_name}': server is disabled

What it means

An explicit connect request targeted a named MCP server whose configuration has `enabled = false`. The pool looks the server up in configured or dynamic servers, finds it, then refuses to start a connection because the server is disabled in config.

Solutions

Enable the server in the MCP config (`enabled = true`) or via the UI/CLI toggle, then retry.
Remove the `enabled = false` / disabled flag from the server's config block.
If the server should not be used, stop calling connect for it and handle it as intentionally unavailable.

Example fix

// before (mcp config)
[server.myserver]
enabled = false
// after
[server.myserver]
enabled = true

Defensive patterns

Strategy: validation

Validate before calling

if let Some(cfg) = pool.server_config(name) {
    if !cfg.is_enabled() {
        return Err(format!("server '{name}' is disabled; enable it before connecting"));
    }
}

Try / catch

match pool.connect(name).await {
    Err(e) if e.to_string().ends_with("server is disabled") => {
        // surface 'server disabled' to the user; do not retry
    }
    r => r?,
}

Prevention

Check `is_enabled()` from the server listing before issuing connects.
Keep disabled servers out of auto-connect/startup lists.
When toggling a server off, also drop pending/retry connect attempts for it.

When it happens

Trigger: Calling the pool's connect method for `server_name` when `server_config.is_enabled()` returns false.

Common situations: Server disabled in mcp config file (`enabled = false` or disabled via UI/CLI), stale dynamic server entry disabled earlier, user forgot they disabled a server after an auth failure.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/bd020ca3328f77d1. Report an issue: GitHub.

Appendix: source

Thrown at crates/tui/src/mcp.rs:3199

            tracing::debug!(
                target: "mcp",
                server = %server_name,
                reason = "reconnect",
                "detached MCP connection for reconnect"
            );
        }

        // Check static config first, then dynamic servers
        let server_config = self
            .config
            .servers
            .get(server_name)
            .cloned()
            .or_else(|| self.dynamic_servers.read().get(server_name).cloned())
            .ok_or_else(|| anyhow::anyhow!("Failed to find MCP server: {server_name}"))?;

        if !server_config.is_enabled() {
            anyhow::bail!("Failed to connect MCP server '{server_name}': server is disabled");
        }

        let mut connection = match McpConnection::connect_with_policy(
            server_name.to_string(),
            server_config,
            &self.config.timeouts,
            self.network_policy.as_ref(),
        )
        .await
        {
            Ok(connection) => connection,
            Err(error) => {
                self.note_connect_failure(server_name, &error);
                if let Some(previous) = previous_connection {
                    tracing::debug!(
                        target: "mcp",
                        server = %server_name,
                        "reconnect failed; restored the previous MCP connection and its last-good catalog"

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