Bug Description

When creating or updating a calendar event with a url field, the server crashes with:

NSInvalidArgumentException - [OC_BuiltinPythonUnicode absoluteString]: unrecognized selector sent to instance

Root Cause

EKEvent.setURL_() expects an NSURL object (from Apple's Foundation framework), but the current code passes a raw Python string directly via PyObjC.

In src/mcp_ical/ical.py:

# Line 99 (create_event)
ekevent.setURL_(new_event.url)  # new_event.url is a Python str

# Line 168 (update_event)
existing_ek_event.setURL_(request.url)  # request.url is a Python str

When macOS tries to call absoluteString on the Python string (expecting it to be an NSURL), it fails because Python strings don't have that Objective-C method.

Steps to Reproduce

1. Start the MCP server
2. Create or update an event with a URL field, e.g.:
   • "Create an event tomorrow with URL https://example.com"
3. Observe the NSInvalidArgumentException crash

Expected Behavior

The URL should be set on the calendar event without errors.

Fix

Convert the Python string to NSURL before passing to setURL_():

from Foundation import NSURL

# create_event
ekevent.setURL_(NSURL.URLWithString_(new_event.url))

# update_event
existing_ek_event.setURL_(NSURL.URLWithString_(request.url))

Environment

• macOS 15 (Sequoia)
• Python 3.12
• PyObjC (latest)