macOS Claude Desktop drops Filesystem `tools/call` after a successful MCP handshake
evanhourigan · ghdev · 2026-07-22
macOS Claude Desktop also drops tools/call for the first-party Filesystem extension
Another issue on anthropics/claude-code says Claude Desktop on macOS completes the full MCP handshake for the built-in Filesystem extension, but never dispatches tools/call.
What the reporter observed
- initialize and tools/list succeed.
- Every tool invocation fails immediately with Failed to call tool <name>.
- No tools/call appears in any relevant log file.
- The bug started overnight on 2026-07-21→22 without any local configuration change.
Why this report matters
The reporter says the same symptom persists even after rollback, reinstall, and connector identity changes, suggesting the issue may be in client-side routing or a server-side rollout rather than local setup.
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