Browser MCP tools disappear mid-session (mcp__browsermcp__* become unavailable)

Problem

Browser MCP server tools (mcp__browsermcp__browser_navigate, mcp__browsermcp__browser_click, etc.) become unavailable mid-session even though the MCP server process is still configured and the browser extension shows "Connected".

Steps to Reproduce

1. Start Claude Code session with Browser MCP configured in ~/.claude/config.json:

``json
"browser": {
"command": "/home/user/.npm-global/bin/mcp-server-browsermcp"
}
``

1. Tools are available at session start (listed as deferred tools in system-reminder)
2. Use the browser tools successfully (navigate, click, type, etc.)
3. After some time or after heavy tool usage, the tools disappear
4. ToolSearch returns "No matching deferred tools found" for any browsermcp query
5. Direct invocation returns Error: No such tool available: mcp__browsermcp__browser_snapshot
6. The browser extension still shows "Connected" status

Expected Behavior

Browser MCP tools should remain available for the entire session as long as the MCP server is running.

Actual Behavior

• Tools work initially, then silently disconnect
• No error message or notification when tools become unavailable
• ToolSearch stops finding them
• Direct calls fail with "No such tool available"
• No way to reconnect the MCP server from within the session

Additional Context

• The MCP server name in config.json is browser but tools are registered as mcp__browsermcp__* (the server self-reports as "browsermcp")
• ListMcpResourcesTool returns empty even when other MCP servers (computer-use, excel-mcp) still work
• The ps aux | grep browsermcp shows no process running after disconnect, suggesting the server process died silently
• Claude Code version: 2.1.76
• OS: Ubuntu Linux 5.15.0-170-generic

Workaround

None found within the session. User must restart Claude Code or run /mcp to reconnect.

Impact

This blocks any workflow that requires sustained browser interaction (e.g., creating GitHub Apps, filling web forms, multi-step browser automation). The disconnect often happens at critical moments during multi-step browser tasks.