Connect Claude Code to tools via MCP changedmcp
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#### Stdio servers that exit or fail to start
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362362
363363### Automatic reconnection
364364
365Claude Code reconnects a remote server that drops mid-session and retries an HTTP or SSE server's first connection after a transient error. Stdio servers are local processes, and Claude Code doesn't reconnect them automatically.
365Claude Code reconnects a remote server that drops mid-session and retries an HTTP or SSE server's first connection after a transient error. For a stdio server, see [Stdio servers that exit or fail to start](#stdio-servers-that-exit-or-fail-to-start).
366366
367367#### Mid-session drops of a remote server
368368
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377377
378378When an HTTP or SSE server's first connection fails with a transient error, such as a 5xx response, a connection refused, or a timeout, Claude Code retries up to three times. If the connection still fails, Claude Code marks the server as failed.
379379
380Claude Code doesn't retry in these cases:
380Those retries don't apply in these cases:
381381
382* A stdio server's first connection. To try it again, see [Stdio servers that exit or fail to start](#stdio-servers-that-exit-or-fail-to-start)
382383* A WebSocket server's first connection
383384* An authentication or not-found error, because it requires a configuration change to resolve. When a [`headersHelper`](#use-dynamic-headers-for-custom-authentication) is the server's only source of the `Authorization` header, Claude Code retries an authentication error anyway, because it re-runs the helper on each attempt and can pick up a fresh credential
384385
386#### Stdio servers that exit or fail to start
387
388To start a stdio server again, read the column that matches what happened to it. Find your row by how you run Claude Code: an interactive session, a `claude -p` run, or an Agent SDK session.
389
390| How you run Claude Code | The server's process exits mid-session | The server's first connection fails |
391| - | - | - |
392| Interactive session | Claude Code marks the server as failed. To start it again, select **Reconnect** from the server's menu in `/mcp` | Claude Code marks the server as failed. To start it again, select **Reconnect** from the server's menu in `/mcp` |
393| `claude -p` run | Claude Code starts the server again the next time Claude calls one of the server's tools, and the call runs once the server connects | The run continues without the server's tools. To have Claude Code try the connection again, start the run again. When a plugin provides the server, new runs skip the connection for 15 minutes after a failure, so wait that long first or [retry sooner](/docs/en/errors.md#skipping-connection-recent-failure-cached) |
394| Agent SDK session | Claude Code starts the server again the next time Claude calls one of the server's tools, and the call runs once the server connects | The session continues without the server's tools. Your code can [reconnect the server](/docs/en/agent-sdk/mcp.md#error-handling) |
395
385396#### Failed discovery requests
386397
387398After a server connects, Claude Code sends it capability discovery requests such as `tools/list`, `prompts/list`, and `resources/list`. Claude Code retries those requests up to three times with short backoff after a transient network or server error. It doesn't retry authentication errors, 4xx responses, or request timeouts.
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494505**Plugin MCP features**:
495506
496507* **Automatic lifecycle**: servers connect and disconnect at these points:
497 * At session startup, Claude Code connects the servers for enabled plugins automatically. In `/mcp`, a remote (HTTP or SSE) plugin server you've used before can show the [`cached` status](#server-status-detail) instead; Claude Code connects it when Claude first calls one of its tools
508 * At session startup, Claude Code connects the servers for enabled plugins automatically. In `/mcp`, a remote (HTTP or SSE) plugin server you've used before can show the [`cached` status](#server-status-detail) instead; Claude Code connects it when Claude first calls one of its tools. When a stdio plugin server's connection failed less than 15 minutes earlier, Claude Code [skips the connection](/docs/en/errors.md#skipping-connection-recent-failure-cached)
498509 * If you enable or disable a plugin during a session, Claude Code connects or disconnects its MCP servers when the change applies. [Apply plugin changes without restarting](/docs/en/plugins/cli-reference.md#reload-plugins) describes when that is. In a session without an interactive terminal, `/reload-plugins` doesn't connect or disconnect plugin MCP servers; those changes take effect in your next session
499510 * When you reload, Claude Code keeps the live connections of plugin servers whose configuration is unchanged, and does the same when you [replace the session's MCP server list](/docs/en/agent-sdk/typescript.md#mcpsetserversresult) from the Agent SDK without naming them
500511 * When you [move the session with `/cd`](/docs/en/permissions#move-the-session-to-another-directory) on v2.1.246 or later, Claude Code connects the servers of plugins the new directory's settings enable and disconnects the servers of plugins that are no longer enabled, so you don't need to run `/reload-plugins` after the move
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