majorlinux
1524ca66d5
New articles: - Python smtplib: Missing Date/Message-ID Headers Break Mail Clients - Fantastical MCP: Permission Denied (macOS Quarantine) - Ubuntu dist-upgrade Repo Quarantine Updated: troubleshooting index, SUMMARY.md nav, WOL article edits. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
98 lines
3.5 KiB
Markdown
98 lines
3.5 KiB
Markdown
---
|
|
title: "Fantastical MCP Server: Permission Denied on Launch (macOS Quarantine)"
|
|
domain: troubleshooting
|
|
category: productivity
|
|
tags: [fantastical, mcp, claude, macos, gatekeeper, quarantine, cowork]
|
|
status: published
|
|
created: 2026-04-26
|
|
updated: 2026-04-26
|
|
---
|
|
|
|
# Fantastical MCP Server: Permission Denied on Launch (macOS Quarantine)
|
|
|
|
Fantastical's MCP server fails to connect in Claude/Cowork with a `Server disconnected` error and no dialog or prompt to explain why. The binary is installed but macOS Gatekeeper silently blocks it from executing.
|
|
|
|
## The Short Answer
|
|
|
|
```bash
|
|
xattr -d com.apple.quarantine "/Users/majorlinux/Library/Application Support/Claude/Claude Extensions/ant.dir.gh.flexibits.fantastical-mcp/server/FantasticalMCP.app"
|
|
```
|
|
|
|
Fully quit and reopen Cowork. Fantastical MCP reconnects cleanly.
|
|
|
|
If the quarantine attribute isn't present, also try setting the executable bit:
|
|
|
|
```bash
|
|
chmod +x "/Users/majorlinux/Library/Application Support/Claude/Claude Extensions/ant.dir.gh.flexibits.fantastical-mcp/server/FantasticalMCP.app/Contents/MacOS/FantasticalMCP"
|
|
```
|
|
|
|
## Why This Happens
|
|
|
|
macOS automatically tags downloaded files with a `com.apple.quarantine` extended attribute. When you launch an app yourself, macOS shows a Gatekeeper dialog — click Open, and the quarantine flag is cleared. But the FantasticalMCP binary is never launched by the user directly; Claude/Cowork spawns it as a subprocess. There's no dialog, and Gatekeeper just returns `Permission denied`. Claude sees the process die immediately and logs `Server disconnected`.
|
|
|
|
This recurs after any Fantastical update that replaces the MCP binary — the new binary comes in quarantined again.
|
|
|
|
## Diagnosis
|
|
|
|
The log tells the whole story. Check:
|
|
|
|
```bash
|
|
tail -n 50 ~/Library/Logs/Claude/mcp-server-Fantastical.log
|
|
```
|
|
|
|
If you see this sequence, it's the quarantine issue:
|
|
|
|
```
|
|
Server started and connected successfully
|
|
Failed to spawn process: Permission denied
|
|
Server transport closed
|
|
Server disconnected.
|
|
```
|
|
|
|
## Full Fix
|
|
|
|
**Step 1 — Remove the quarantine flag:**
|
|
|
|
```bash
|
|
xattr -d com.apple.quarantine \
|
|
"/Users/majorlinux/Library/Application Support/Claude/Claude Extensions/ant.dir.gh.flexibits.fantastical-mcp/server/FantasticalMCP.app"
|
|
```
|
|
|
|
**Step 2 — Verify the attribute is gone:**
|
|
|
|
```bash
|
|
xattr "/Users/majorlinux/Library/Application Support/Claude/Claude Extensions/ant.dir.gh.flexibits.fantastical-mcp/server/FantasticalMCP.app"
|
|
```
|
|
|
|
Should return empty or only non-quarantine attributes. If `com.apple.quarantine` is still listed, re-run step 1.
|
|
|
|
**Step 3 — Fully quit and reopen Cowork:**
|
|
|
|
Cmd+Q (not just close the window). Closing the window leaves the MCP host process running — it won't retry the failed server until the app fully relaunches.
|
|
|
|
**Step 4 — Verify connection:**
|
|
|
|
Check the log again:
|
|
|
|
```bash
|
|
tail -n 10 ~/Library/Logs/Claude/mcp-server-Fantastical.log
|
|
```
|
|
|
|
You should see `Server started and connected successfully` with no `Permission denied` line following it.
|
|
|
|
## After a Fantastical Update
|
|
|
|
If this breaks again after Fantastical auto-updates, re-run the `xattr -d` command from Step 1. The update replaces the binary and macOS re-quarantines the new one.
|
|
|
|
## MCP Log Locations
|
|
|
|
| Log | Path |
|
|
|-----|------|
|
|
| Fantastical MCP | `~/Library/Logs/Claude/mcp-server-Fantastical.log` |
|
|
| All MCP servers | `~/Library/Logs/Claude/mcp*.log` |
|
|
| Combined MCP log | `~/Library/Logs/Claude/mcp.log` |
|
|
|
|
## Related
|
|
|
|
- [[Fantastical Google Sync Error Flood — Phantom Calendars Fixed via syncselect]]
|
|
- MCP debugging docs: https://modelcontextprotocol.io/docs/tools/debugging
|