1. The "No Any" Policy

Rule: Explicit any is forbidden. Detection: grep -r ": any" src/ Fixes:

Known Shape: Define an interface or type.
Unknown Shape: Use unknown + Type Guards (Zod parsing or typeof checks).
Generic: Use generics <T>.

2. Strict Null Checks

Rule: All nullable fields must be explicit.

Bad: function(u: User) { ... } // what if u is null?
Good: function(u: User | undefined) { ... }

3. Exhaustiveness Checking

Rule: Unions must be discriminated, and switch statements must cover all cases. Pattern:

type Action = { type: 'A' } | { type: 'B' };
switch (action.type) {
  case 'A': ...
  case 'B': ...
  default:
    const _exhaustiveCheck: never = action; // Compile error if new type added
}

Workflow

Audit Mode

Command: /ts-check

Run project type checker: npm run typecheck or tsc --noEmit.
Parse output errors.
Group by file.

Repair Mode

Command: /ts-fix <file>

Read file.
Identify any or casting (as).
Refactor:
- Infer: Look at usage to derive the type definition.
- Define: Create interface at top of file (or types.ts).
- Apply: Replace any with new Type.

Constraints

Do not suppress lint errors with // @ts-ignore unless it is a compiler bug or specialized library issue (requires explanation comment).
Do not change runtime logic; only type definitions.

Outputs

Type safety report and remediation checklist.

Related Skills

/api-contracts-and-validation - Define safe contracts

ts-strict-guardian

Typescript Strict Guardian Skill

Overview

Usage

Identity

Policies