Navigator Role — Adversarial Pair for Driver Agents

Use a navigator (adversarial second agent) when the driver is doing work where mistakes compound silently: commit restaging, behavioral extraction, multi-file refactors, or any task where a subtle regression won't cause a test failure but will ship broken semantics.

When to Spawn a Navigator

• Restaging commits (fixup+rebase changes behavioral identity)
• Extracting shared utilities from duplicated code (lazy vs eager evaluation)
• Multi-file type signature changes (widening can silently drop constraints)
• Staging selective hunks into bisectable commits (import ordering, dependency graphs)

Navigator's Job

The navigator does NOT confirm the driver's work is correct. The navigator finds where it ISN'T:

1. Behavioral identity — Does the refactored code do exactly what the original did? Watch for eager-to-lazy, null-at-creation, and import-ordering regressions.
2. Staging completeness — After fixup+autosquash, are all dependent changes in the right commit? A fix applied after initial staging can be missed.
3. Spec AC gaps — Does the implementation satisfy the acceptance criteria literally, not just in spirit? (e.g., "use the proper type" means the named type, not an inline structural equivalent)
4. Cross-file consistency — When a signature widens in file A, do all callers in files B, C, D pass the right shape?

How to Use

Spawn as crew-challenger with adversarial instructions:

Your job is to find where the work DOESN'T match the plan — not to confirm it does.
Check: behavioral identity after extraction, staging completeness after rebase,
AC satisfaction (literal, not spirit), cross-file type consistency.

Evidence

• spec-002: GoldHawk navigator caught pre-claim timing regression
• spec-003: QuickRaven caught FileReservation not staged after fixup-rebase (import was applied after initial staging, so fixup missed it)
• spec-003: QuickRaven caught stuck-timer eager taskId capture (lobby.assignedTaskId is null at creation — must use lazy getter)
• spec-003: QuickRaven caught skip comment missing "why" rationale (R8 AC said "and why", comment only had "what")