feat: add schedule creation and update functionality

[dmcclure-pdt]

Description

This PR adds schedule creation and update support to the PagerDuty MCP server, enabling users to create and manage complex on-call schedules directly through the MCP interface. The implementation follows the PagerDuty API specification for schedule operations, allowing for configuration of:

• Basic schedule properties (name, description, timezone)
• Schedule layers with rotation turn lengths
• Multiple users in each rotation layer
• Time-based restrictions for schedule layers (daily and weekly)
• Starting dates and rotation virtual start settings
• Schedule updates with special handling for layer management

Issue number: #XXX (replace with actual issue number if applicable)

Type of change

• New feature (non-breaking change which adds functionality)
• Fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation only

Checklist

• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• Changes generate no new warnings
• PR title follows conventional commit semantics

Additional Notes

Feature Overview

• Added create_schedule tool for schedule creation operations
• Added update_schedule tool for schedule updates
• Implemented ScheduleCreateRequest, ScheduleUpdateRequest, and related models
• Added helper functions for working with schedule layers
• Included proper validation for schedule parameters and restrictions
• Updated tool registration in __init__.py
• Added comprehensive tests for the new functionality

Testing

• Tested with various complex schedule scenarios:
  • 24x7x365 rotations
  • Weekly rotations with multiple users
  • Follow-the-Sun global support schedules
  • Business hours vs after-hours schedules
  • Holiday and PTO coverage with overrides
  • Schedules with daily and weekly restrictions

Test Prompts

The following test prompts were used to verify the functionality:

# Test Case 1: Create Schedule
using the pagerduty-mcp, Create a new on-call schedule with the following details:
  - Name: "Engineering Team Rotation"
  - Description: "Weekly rotation for engineering team"
  - Time Zone: "America/New_York"
  - Layer Name: "Primary On-Call"
  - Rotation start date: January 1, 2026, at 9:00 AM ET
  - Rotation length: 7 days (604800 seconds)
  - Add four team members to the schedule
  - Add a daily restriction that only runs from 9 AM to 5 PM (8 hours)

# Test Case 2: Update Schedule Properties
using the pagerduty-mcp, update the schedule with these changes:
  - Rename to "Engineering Team Primary Rotation"
  - Update description to "Weekly rotation schedule for primary engineering contacts"
  - Add a new user to the rotation after user 2
  - Change the rotation length to 3 days (259200 seconds)
  - Add a weekend restriction (no on-call assignments on weekends)
  - Keep the 9 AM to 5 PM weekday restriction

# Test Case 3: Basic Property Update
using the pagerduty-mcp, Update the schedule with these changes:
  - Rename to "Engineering Team Primary Rotation (Updated)"
  - Update description to "Weekly rotation for engineering team with weekend coverage"
  - Keep all existing layers intact

Schedule Update Patterns

The implementation includes special handling for schedule updates, which have unique behavior in the PagerDuty API:

1. Basic property updates (name, description, timezone) can be done without affecting schedule layers by using an empty schedule_layers=[] parameter
2. Layer updates require providing all layers that should be present in the final schedule
3. Helper functions are available to analyze differences between existing and desired layers

[kyub]

👍 for this. This functionality is a requirement for us to make use of the PagerDuty MCP.

[kyub]

@imjaroiswebdev Can this PR be merged please?

[imjaroiswebdev]

Hi @kyub, thank you for sharing how interested you are in leveraging this feature. This PR will get merged hopefully before the end of this same week.

[kyub]

Great, thanks!