Single Source Helpers

When code review finds duplicated logic or repeated formatting/constants, treat it as a “single source of truth” violation. Factor shared logic into a helper/module and reuse it everywhere; avoid hardcoded literals where an existing helper/constant exists; and keep established idioms consistent.

Guidelines:

• Duplicate logic across code paths (e.g., launch vs resume, attach vs subscribe) should be extracted into a shared helper function placed near related constants/contracts.
• Duplicate protocol/type definitions should be aliased to one canonical type (e.g., type New = Old;) or imported from a shared module.
• Hardcoded strings/format separators used for assertions or UI formatting should become shared constants (or reuse an existing formatter helper) so updates don’t require hunting multiple sites.
• Maintain consistent style/idioms for readability (e.g., prefer the existing timer.unref?.() pattern over verbose type guards when they’re equivalent).
• Don’t keep misleading no-op steps (e.g., assigning undefined immediately overwritten on the next line); remove dead assignments when refactoring.

Example (helper extraction):

// helpers.ts
export function extractParentToolNames(generationConfig: unknown): string[] {
  // ... shared extraction logic ...
  return names;
}

// call sites
const names = extractParentToolNames(generationConfig);

Example (constant for repeated literals in tests):

const INITIAL_CONTENT = 'original content';
expect(input.content).not.toBe(INITIAL_CONTENT);