model-first-reasoning_skill

Overview

This skill applies Model-First Reasoning (MFR) to code generation tasks by enforcing a strict two-phase workflow: produce an explicit model first, then implement only from that frozen model. It is designed to reduce hallucinations and drift by turning the model into a contract that governs planning, coding, and testing.

How this skill works

Phase 1 produces an inspectable model (entities, state, actions, constraints, goals, unknowns) with no code or implementation steps. A mandatory model audit (coverage, operability, consistency, testability) must pass before moving on. Phase 2 implements only items defined in the audited model, writes tests for every constraint, and uses MODEL PATCH if any model change is required.

When to use it

• When the task requests “model-first”, “MFR”, or “formal modeling before coding”
• Complex state machines with nontrivial transitions and invariants
• Business logic that must enforce invariants and strict constraints
• Multi-step workflows or protocols where operations depend on state
• Safety-critical or high-assurance features where correctness matters

Best practices

• Produce a complete, explicit model before any implementation or planning
• List unknowns in the model; stop and resolve them before Phase 2
• Run the model audit and fix coverage, operability, consistency, and testability issues
• Map each requirement to exactly one model element (constraint, goal, or action)
• Implement tests that directly validate each constraint (test oracle per constraint)
• If new info is needed during implementation, emit a minimal MODEL PATCH and restart Phase 2

Example use cases

• Designing a shopping cart with limits, uniqueness, and total-cost invariants
• Specifying and implementing a protocol or state machine (e.g., payment workflow)
• Creating data transformation pipelines where input/output contracts must hold
• Implementing authorization rules with invariants that must never be violated
• Building multi-step onboarding flows where steps depend on prior state