Scheduler Correctness Power

A reusable Kiro Power for reviewing deterministic schedulers against correctness properties: purity, conservation, capacity, deadline compliance, task exclusion, determinism, and ordering.

Version: 1.0.0
Author: Hemanth

What It Does

This power provides a structured skill (review-scheduler) and reference scenarios to systematically review any deterministic scheduler—academic projects, production systems, or implementations in any language. It distinguishes between:

• Code inspection (reading source to verify properties)
• Test evidence (examining test assertions and property tests)
• Never inventing results

Use it to:

• Audit a scheduler before deployment
• Verify correctness properties are tested
• Review a new scheduler implementation against a spec
• Compare two scheduler implementations for correctness
• Teach scheduler design and verification practices

Installation

This power is installed through the Kiro IDE Powers panel:

1. Powers panel → Add Custom Power
2. Choose Import power from a folder
3. Navigate to powers/scheduler-correctness in your workspace
4. Click Import

The power is now installed and ready to activate.

Usage

To use the power:

1. Activate it — Open a chat session with the default agent and request to activate the installed scheduler-correctness Power
2. Apply the skill — The agent activates and uses the review-scheduler skill to audit a scheduler
3. Review findings — The skill provides 8 structured steps to verify correctness properties and reference scenarios for validation

The power guides you to:

• Locate the scheduling function and types
• Verify purity (no global state, explicit date input)
• Check conservation invariant (allocated + unschedulable = estimated)
• Verify capacity, deadline, and ordering constraints
• Distinguish code inspection from test evidence

What's Inside

scheduler-correctness/
├── plugin.json                          # Power manifest
├── README.md                            # This file
└── skills/
    └── review-scheduler/
        ├── SKILL.md                     # Main review skill (8 properties)
        └── references/
            └── scenarios.md             # 8 concrete test scenarios with inputs/outputs

Files

• plugin.json — Metadata: name, version, description, keywords
• SKILL.md — Step-by-step review process for each correctness property:
  1. Locate scheduler and types
  2. Check purity and explicit date inputs
  3. Verify minute/resource conservation
  4. Check daily capacity compliance
  5. Verify deadline enforcement
  6. Check completed-task exclusion
  7. Verify determinism
  8. Check sort order
  • Reporting guidelines: distinguish code inspection from tests
• scenarios.md — 8 concrete scenarios with fixed dates, inputs, and expected outputs:
  • Overloaded capacity
  • Overdue tasks
  • Completed tasks
  • Split across multiple days
  • Equal deadline with priority tie-breaking
  • Equal deadline/priority with ID tie-breaking
  • Zero-capacity days
  • Determinism verification

Key Principles

1. No MCP server needed — This power contains only documentation and structured guidance. It's a skill and reference, not an automated tool.

2. Inspect, don't execute — The skill teaches code review; tests are examined, not run. (Tests can be run separately in the scheduler project.)

3. Concrete scenarios — All reference scenarios use explicit dates (YYYY-MM-DD), fixed task IDs, and precise expected outputs. No hand-waving.

4. Never invent results — Report only what code and tests show. Use clear language:

   • ✅ "The function does not call new Date()" (code inspection)
   • ✅ "Test testConservation verifies allocated + unschedulable === estimatedMinutes" (test evidence)
   • ❌ "The scheduler is probably deterministic" (speculation)

5. File references throughout — Always cite file.ts:lineNumber when reporting findings.

Use Cases

1. Academic Project Review

Student implements a class scheduler. Use the skill to audit the code against the 8 properties. Consult scenarios to manually trace behavior. Report findings with file references.

2. Production Deployment Checklist

Before deploying a new scheduler, review using this power to verify:

• Conservation invariant (tested)
• Capacity constraints (tested)
• Deadline compliance (tested)
• Determinism (property tests exist)

3. Comparative Analysis

Two team members implement schedulers. Use the skill and scenarios to compare both for correctness, using the same criteria.

4. Learning Tool

Learn scheduler correctness properties by reading the skill, then applying each step to an example scheduler (e.g., StudySprint).

StudySprint Example

The StudySprint application includes a pure scheduler (src/scheduler/scheduler.ts) that can be reviewed using this power:

Activate the scheduler-correctness power.

Review StudySprint's scheduler:

1. Location: src/scheduler/scheduler.ts, function schedule()
2. Types: src/types.ts (Task, Availability, ScheduleEntry, ScheduleResult)
3. Tests: src/tests/scheduler*.ts (unit, property, and regression tests)

Check each property from the skill:
- ✅ Pure: no new Date(), explicit today parameter
- ✅ Conservation: verified by property tests with fc.assert
- ✅ Capacity: tests verify per-day totals ≤ available
- ✅ Deadline: tests verify no entries past deadline
- ✅ Exclusion: completed tasks filtered before scheduling
- ✅ Determinism: property tests run scheduler twice, compare outputs
- ✅ Ordering: deadline ASC → priority ASC → ID ASC

Report your findings with file and line references.

Extensibility

To extend this power for other scheduler types:

1. Add a new scenario to references/scenarios.md (e.g., "Network task scheduling", "Resource allocation")
2. Add a new property to SKILL.md (e.g., "Resource conflict detection", "Fairness across users")
3. Create a variant skill (e.g., review-scheduler-parallel.md for concurrent schedulers)

All follow the same structure: explicit steps, file references, and concrete scenarios.

License

This power is provided as-is for review and educational purposes.