Claude Code does not respond to MCP notifications/tools/list_changed

Summary

Claude Code does not respond to notifications/tools/list_changed MCP notifications. When an MCP server dynamically enables/disables tools and sends the notification, Claude Code does not update its tool list.

MCP Specification Reference

According to the MCP Tools Specification:

Servers that support tools MUST declare the tools capability. listChanged indicates whether the server will emit notifications when the list of available tools changes.

The capability is declared as:

{
  "capabilities": {
    "tools": {
      "listChanged": true
    }
  }
}

When the list of available tools changes, servers that declared the listChanged capability SHOULD send a notification.

The notification format is:

{
  "jsonrpc": "2.0",
  "method": "notifications/tools/list_changed"
}

Upon receiving this notification, clients are expected to re-fetch the tool list via tools/list.

Expected Behavior

1. MCP server sends notifications/tools/list_changed notification
2. Claude Code re-fetches the tool list via tools/list
3. Claude Code sees the newly enabled/disabled tools

Actual Behavior

1. MCP server sends notifications/tools/list_changed notification
2. Claude Code ignores the notification
3. Claude Code's tool list remains unchanged from initial connection

Minimal Reproduction

I've created a minimal reproduction case: https://github.com/eastlondoner/mcp-dynamic-tools-repro

Setup

git clone https://github.com/eastlondoner/mcp-dynamic-tools-repro
cd mcp-dynamic-tools-repro
bun install  # or npm install
bun start    # starts MCP server on http://localhost:3002/mcp

The .mcp.json is already configured:

{
  "mcpServers": {
    "dynamic-tools-repro": {
      "type": "http",
      "url": "http://localhost:3002/mcp"
    }
  }
}

Test Steps

1. Start the MCP server (bun start)
2. Start Claude Code in the same directory (claude)
3. Ask Claude to call get_status - shows secretToolEnabled: false
4. Ask Claude to call toggle_secret_tool with enable=true
5. Server logs show: Enabling secret_tool, isConnected: true
6. Ask Claude to call secret_tool

Expected: Claude calls secret_tool successfully

Actual: Claude says it doesn't have access to secret_tool

Server Architecture

The test server has 3 tools:

| Tool | Initially Available | Description |
|------|---------------------|-------------|
| get_status | Yes | Shows current state |
| toggle_secret_tool | Yes | Enables/disables secret_tool |
| secret_tool | No (disabled) | Only visible after enabling |

When toggle_secret_tool(enable=true) is called, the MCP SDK's handle.enable() method is used, which internally sends notifications/tools/list_changed.

Environment

• Claude Code version: 2.0.62
• MCP SDK version: 1.25.1
• Runtime: Bun 1.3.5
• OS: macOS

Related

• GitHub Discussion #76 mentions "Claude Desktop doesn't support notifications/tools/list_changed at the moment"
• This appears to also apply to Claude Code

Use Case

This is blocking my development of a Minecraft client with an MCP co-pilot interface. I want to dynamically show/hide contextual tools (like open_container when looking at a chest) based on game state. The server correctly sends notifications when tools become available, but Claude Code never sees them.