Claude Desktop app caches MCP tool descriptions — web version doesn't

Description

MCP tool descriptions are cached in the Claude Desktop app (Mac/Windows), causing AI to use outdated parameter schemas when calling MCP tools. The web version (claude.ai) correctly fetches the latest tool descriptions on each session.

Steps to reproduce

1. Set up a remote MCP server (Streamable HTTP transport)
2. Connect it in both Claude Desktop app and claude.ai web
3. Update the MCP tool's inputSchema or description on the server side
4. Use the tool in claude.ai web — AI sees the updated schema and fills parameters correctly
5. Use the tool in Claude Desktop app — AI still uses the old cached schema, leading to incorrect parameter formatting

Expected behavior

Both the Desktop app and web version should fetch the latest tool descriptions from the MCP server, or at minimum respect tools/list_changed notifications to invalidate the cache.

Actual behavior

The Desktop app continues using stale tool descriptions even after the server has updated them. This causes the AI to fill in parameters incorrectly based on outdated schemas.

Impact

For MCP servers that iterate on their tool schemas (adding/renaming parameters, changing descriptions), Desktop app users get stuck with outdated schemas until the cache is somehow cleared. This is particularly problematic during active development.

Environment

• Claude Desktop app (Mac)
• Remote MCP server using Streamable HTTP transport
• Server sends tools/list_changed notification on schema updates