Distinct from define-language and deepen-architecture: Use this skill to stress-test a plan through a grilling interview that resolves domain model decisions and captures invariants. Use define-language to produce a canonical glossary of terms. Use deepen-architecture to find module-level refactoring opportunities in code.

Interview me relentlessly about every aspect of this plan until we reach a shared understanding. Walk down each branch of the design tree, resolving dependencies between decisions one-by-one. For each question, provide your recommended answer.

HARD GATE — Capture invariants (what MUST always be true) and state machines (what transitions are legal) for core entities. If these are fuzzy, design will fail.

Ask the questions one at a time, waiting for feedback on each question before continuing.

If a question can be answered by exploring the codebase, explore the codebase instead.

During codebase exploration, also look for existing documentation:

Most repos have a single context:

/
├── specs/
│   ├── CONTEXT.md
│   └── adr/
│       ├── 0001-event-sourced-orders.md
│       └── 0002-postgres-for-write-model.md
└── src/

If a specs/tech-architecture/tech-stack.md exists, the repo has multiple contexts. The map points to where each one lives:

/
├── specs/
│   ├── CONTEXT-MAP.md
│   └── adr/                          ← system-wide decisions
└── src/
    ├── ordering/
    │   └── specs/
    │       ├── CONTEXT.md
    │       └── adr/                  ← context-specific decisions
    └── billing/
        └── specs/
            ├── CONTEXT.md
            └── adr/

Create files lazily — only when you have something to write. If no specs/tech-architecture/tech-stack.md exists, create it when the first term is resolved. If no specs/adr/ exists, create it when the first ADR is needed.

When the user uses a term that conflicts with the existing language in specs/tech-architecture/tech-stack.md, call it out immediately. “Your glossary defines ‘cancellation’ as X, but you seem to mean Y — which is it?”

When the user uses vague or overloaded terms, propose a precise canonical term. “You’re saying ‘account’ — do you mean the Customer or the User? Those are different things.”

When domain relationships are being discussed, stress-test them with specific scenarios. Invent scenarios that probe edge cases and force the user to be precise about the boundaries between concepts.

When the user states how something works, check whether the code agrees. If you find a contradiction, surface it: “Your code cancels entire Orders, but you just said partial cancellation is possible — which is right?”

When a term is resolved, update specs/tech-architecture/tech-stack.md right there. Don’t batch these up — capture them as they happen. Use the format in CONTEXT-FORMAT.md.

Don’t couple specs/tech-architecture/tech-stack.md to implementation details. Only include terms that are meaningful to domain experts.

Only offer to create an ADR when all three are true:

1. Hard to reverse — the cost of changing your mind later is meaningful
2. Surprising without context — a future reader will wonder “why did they do it this way?”
3. The result of a real trade-off — there were genuine alternatives and you picked one for specific reasons

If any of the three is missing, skip the ADR. Use the format in ADR-FORMAT.md.

When the plan touches shared state, async, or multi-threaded code:

• List every shared mutable location (globals, singletons, module-level caches).
• For each: who reads, who writes, synchronization mechanism (lock, actor, immutable copy).
• Flag race risks (check-then-act, non-atomic read-modify-write) with severity.
• Record findings in specs/tech-architecture/tech-stack.md under ## Concurrency or in an ADR if architectural.

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