discuss-phase

<objective>
Extract implementation decisions that downstream agents need — researcher and planner will use CONTEXT.md to know what to investigate and what choices are locked.

**How it works:**
1. Analyze the phase to identify gray areas (UI, UX, behavior, etc.)
2. Present gray areas — user selects which to discuss
3. Deep-dive each selected area until satisfied
4. Create CONTEXT.md with decisions that guide research and planning

**Output:** `{phase}-CONTEXT.md` — decisions clear enough that downstream agents can act without asking the user again
</objective>

<execution_context>
@./references/phase-discuss.md
@./references/context-template.md
</execution_context>

<context>
Phase number: $ARGUMENTS (required)

**Load project state:**
@.planning/STATE.md

**Load roadmap:**
@.planning/ROADMAP.md
</context>

<process>
1. Validate phase number (error if missing or not in roadmap)
2. Check if CONTEXT.md exists (offer update/view/skip if yes)
3. **Analyze phase** — Identify domain and generate phase-specific gray areas
4. **Present gray areas** — Multi-select: which to discuss? (NO skip option)
5. **Deep-dive each area** — 4 questions per area, then offer more/next
6. **Write CONTEXT.md** — Sections match areas discussed
7. Offer next steps (research or plan)

**CRITICAL: Scope guardrail**
- Phase boundary from ROADMAP.md is FIXED
- Discussion clarifies HOW to implement, not WHETHER to add more
- If user suggests new capabilities: "That's its own phase. I'll note it for later."
- Capture deferred ideas — don't lose them, don't act on them

**Domain-aware gray areas:**
Gray areas depend on what's being built. Analyze the phase goal:
- Something users SEE → layout, density, interactions, states
- Something users CALL → responses, errors, auth, versioning
- Something users RUN → output format, flags, modes, error handling
- Something users READ → structure, tone, depth, flow
- Something being ORGANIZED → criteria, grouping, naming, exceptions

Generate 3-4 **phase-specific