fetch MCP: ImportError cannot import name 'McpError' from 'mcp.shared.exceptions'

Fix fetch MCP ImportError: cannot import name 'McpError' from 'mcp.shared.exceptions'

TL;DR

Pin the SDK below 2.0: run uvx --with "mcp<2" mcp-server-fetch. The mcp 2.0.0 release renamed McpError to MCPError, and the fetch server (released before 2.0) imports the old name, so every fresh unpinned install crashes on startup.

The exact error:

ImportError: cannot import name 'McpError' from 'mcp.shared.exceptions'. Did you mean: 'MCPError'?

Steps

1. Confirm the SDK version mismatch

Run the server by hand:

uvx mcp-server-fetch

Success check: the traceback mentions mcp_server_fetch/server.py importing McpError and suggests MCPError. That confirms this exact problem.

2. Pin mcp below 2.0

Change your MCP config to inject the pinned dependency:

{
  "mcpServers": {
    "fetch": {
      "command": "uvx",
      "args": ["--with", "mcp<2", "mcp-server-fetch"]
    }
  }
}

Success check: restarting the client, the fetch server connects and fetch appears in the tool list.

3. Verify the handshake manually (optional)

uvx --with "mcp<2" mcp-server-fetch

then send an initialize frame over stdin. Success check: the server answers instead of exiting with code 1.

When this applies

• uvx mcp-server-fetch exits immediately with the McpError ImportError.
• Fresh installs broke around or after the mcp 2.0.0 release; older cached environments still work.
• Also affects mcp-server-time and mcp-server-git (same ImportError / missing attributes); the same --with "mcp<2" fix applies.

When it does not apply

• 404 Not Found from the npm registry for @modelcontextprotocol/server-fetch. That package never existed on npm; the reference fetch server is the PyPI package mcp-server-fetch run through uvx.
• The server starts but a specific URL fails to fetch. That is a per-URL problem (robots, auth, JS rendering), not the startup crash.

Tool compatibility

• mcp-server-fetch (PyPI), releases before the mcp<2 cap (e.g. 2026.7.10)
• mcp Python SDK 2.0.0+
• uv / uvx launcher
• Claude Desktop, Claude Code, Cursor

Why it happens

The fetch server's pyproject.toml declared mcp>=1.1.3 with no upper bound. When mcp 2.0.0 shipped and renamed the exception class McpError to MCPError (plus replacing the low-level Server decorators), every fresh dependency resolution pulled 2.0.0 and the old import broke. uvx does not pin, so all new installs were affected from 2026-07-28 until the upstream cap landed.

Edge cases

• If you already have a working cached environment, do not "fix" it; the pin only matters for fresh resolves.
• Long term, the servers are being ported to the 2.x API; once your installed fetch release declares mcp>=2 support, drop the --with override.
• On Windows the same crash appears; the fix is identical.