Code in Desktop App significantly slower than VS Code extension — MCP tool definitions a likely contributor

Preflight Checklist

• [x] I have searched existing issues for similar behavior reports
• [x] This report does NOT contain sensitive information (API keys, passwords, etc.)

Type of Behavior Issue

Other unexpected behavior

What You Asked Claude to Do

Description:

Claude Code in the Windows desktop app is noticeably slower than the VS Code extension, with frequent "compacting conversation" events even in relatively short sessions. The same tasks on the same project run much faster in VS Code.

Environment:

Windows 11 Home
Claude Desktop App (latest version)
Multiple MCP servers configured (Home Assistant, Canva, Make, Notion, Chrome DevTools)

What Claude Actually Did

Frequent compacting, even on short conversations
Noticeably slower response times compared to VS Code extension
Same project, same settings, same model — desktop app is consistently slower

Expected Behavior

None of the above
Possible contributor — MCP tool overhead:
All MCP tool definitions are sent with every request, regardless of whether they're needed. With multiple MCP servers active, this adds hundreds of tool definitions to every single message, eating into the context window quickly.

Feature request:
It would be great if MCP servers could be lazy-loaded — only injecting their tool definitions when explicitly invoked (e.g., via a slash command or keyword). This would significantly reduce context bloat for users with multiple MCP servers configured.

Alternatively, allowing per-project MCP server profiles that can be toggled easily would help users manage context overhead.

Workaround:
Disabling most MCP servers globally and only enabling them per-project helps, but it's manual and easy to forget.

Files Affected

Permission Mode

Accept Edits was ON (auto-accepting changes)

Can You Reproduce This?

Yes, every time with the same prompt

Steps to Reproduce

_No response_

Claude Model

Sonnet

Relevant Conversation

Impact

Critical - Data loss or corrupted project

Claude Code Version

Claude for Windows : Version 1.1.6041 (62e193)

Platform

Anthropic API

Additional Context

_No response_