[BUG] Persistent MCP error: tools.77.FrontendRemoteMcpToolDefinition.name - Account-level corruption

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Issue Title:
Persistent MCP error: tools.77.FrontendRemoteMcpToolDefinition.name - Account-level corruption
Description:

Error: tools.77.FrontendRemoteMcpToolDefinition.name
Product: Claude Desktop and Claude.ai (web)
Impact: Blocking access to paid account

Steps to Reproduce:

Attempted to configure ElevenLabs MCP server
Error appeared and persists across all platforms
Full local cleanup performed (config, cache, logs deleted)
Reinstalled Claude Desktop
Error still appears on both desktop and web

What I've Tried:

Deleted all local Claude data (~/Library/Application Support/Claude, caches, logs, preferences)
Reinstalled Claude Desktop
Tested on claude.ai web interface
Deleted conversations
Disconnected MCP servers via UI

Expected Behavior:
MCP error should clear after local cleanup
Actual Behavior:
Error persists across platforms, indicating server-side MCP registry corruption
Request:
Clear all MCP/remote tool state associated with account: [darkhorse309@gmail.com](mailto:darkhorse309@gmail.com)
You can file this at https://github.com/anthropics/claude-code/issues

What Should Happen?

Expected Behavior:
MCP error should clear after local cleanup
Actual Behavior:
Error persists across platforms, indicating server-side MCP registry corruption
Request:
Clear all MCP/remote tool state associated with account: [darkhorse309@gmail.com](mailto:darkhorse309@gmail.com)
You can file this at https://github.com/anthropics/claude-code/issues

Error Messages/Logs

Error: tools.77.FrontendRemoteMcpToolDefinition.name
    Product: Claude Desktop and Claude.ai (web)
    Impact: Blocking access to paid account

Steps to Reproduce

<img width="1792" height="1120" alt="Image" src="https://github.com/user-attachments/assets/848c6a55-e0e5-45bf-8d25-b800daf8e772" />

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Sonnet 4.6

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

<img width="1486" height="307" alt="Image" src="https://github.com/user-attachments/assets/27155ffd-7100-4a10-bc76-b496bab30fc0" />

<img width="533" height="516" alt="Image" src="https://github.com/user-attachments/assets/23b41121-6dc2-4677-bffd-b3534fd3abf1" />