/plan

name: plan
description: "Plan features spanning multiple domains: billing (Stripe), auth (RBAC), real-time (Presence), webhooks, jobs (Oban). Use when designing interconnected systems or converting review findings into tasks."
effort: high
argument-hint: <feature description OR path to review/plan file>

Plan Elixir/Phoenix Feature

Plan a feature by spawning Elixir specialist agents, then output structured plan with checkboxes.

What Makes /phx:plan Different from /plan

1. Spawns Elixir specialist agents for research 2. Plans with `[ecto]`, `[liveview]`, `[oban]` task routing 3. Checks for Iron Law compliance in the plan 4. Includes `mix compile/format/credo/test` verification 5. Understands Phoenix context boundaries

Usage

/phx:plan Add user avatars with S3 upload
/phx:plan .claude/plans/notifications/reviews/notifications-review.md
/phx:plan Implement notifications --depth deep
/phx:plan .claude/plans/auth/plan.md --existing

Arguments

• `$ARGUMENTS` = Feature description, review file, or existing plan
• `--depth quick|standard|deep` = Planning depth (auto-detected)
• `--existing` = Enhance an existing plan with deeper research

Workflow

1. **Gather context** — File path (skip to agents), brainstorm interview.md (skip clarification), clear description, or vague 2. **Clarify if vague** — Ask questions ONE at a time (skip if brainstorm interview.md exists with Status: COMPLETE) 3. **Detect depth** — Auto-detect quick/standard/deep 4. **Runtime context** (Tidewave) — Gather live schemas, routes, and warnings before spawning agents (direct path only — the research orchestrator gathers its own) 5. **Spawn research** — Selective, based on need. **0–2 agents**: spawn directly in parallel. **3+ agents** (broad multi-context feature): determine the effective maximum nesting depth. Use an explicit positive-integer `CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH` value first; when it is unset, inspect `claude --version` (the default is 1 in 2.1.217–2.1.218 and 3 in 2.1.219+). If the version is unavailable, conservatively use 1. At depth 3+, spawn ONE `planning-orchestrator` to run and compress the fan-out. At depth 1 or 2, keep orchestration in this main session: spawn the selected specialist agents directly, wait for them, then spawn `phx:context-supervisor` directly if compression is needed. Never spawn an orchestrator that cannot delegate. Read only the resulting digest and `summaries/consolidated.md`. If `TaskCreate` is in your tool list (never ToolSearch for it), create a task per spawn: `TaskCreate({subject: "{Agent} research", activeForm: "Researching..."})`, mark `in_progress` on spawn, `completed` when done 6. **Wait for ALL agents** — Do NOT proceed until all return "completed". NEVER write plan while any agent is still running 7. **Breadboard** (LiveView) — System map for multi-page features 8. **Completeness check** — required when planning from review 9. **Split decision** — One plan or multiple, concrete options 10. **Generate plan** — Checkboxes, phased tasks, code patterns. Also create `plans/{slug}/scratchpad.md` for decisions and dead-ends 11. **Self-check** (deep only) — Three questions in Risks section 12. **Present and ask** — STOP, show summary, let user decide

**When planning from review**: Every finding must appear in the plan — either as a task OR explicitly deferred by the user.

See `${CLAUDE_SKILL_DIR}/references/planning-workflow.md` for detailed step-by-step.

--existing Mode (Deepening)

Enhances an existing plan instead of creating a new one:

1. Load plan, search `.claude/solutions/` for known risks 2. Spawn SPECIALIST agents (not Explore) for thin sections. Each agent writes to `.claude/plans/{slug}/research/` and returns only a 500-word summary. Same agent selection rules 3. Wait for ALL agents (mark tasks `completed` as each finishes) 4. Add implementation detail, resolve spikes, add verification 5. Present diff summary — **NEVER delete existing tasks**

Iron Laws

1. **NEVER auto-start /phx:work** — Always present plan and ask 2. **Research before assuming** — Web-search unfamiliar tech 3. **Spawn agents selectively** — Only relevant, not all 4. **NEVER write plan while agents still running** 5. **NEVER skip input findings** — Every finding MUST have a task 6. **Do NOT spawn hex-library-researcher for existing deps** 7. **Skip research when planning from review/investigation** — When input is a review file or `/phx:investigate` output, the findings ARE the research. Do NOT spawn agents to re-discover what the review already found. Convert findings directly to plan tasks. (Confirmed: 56-session analysis showed same findings discovered 3-4x across review→investigate→plan phases, wasting ~96K tokens)

Integration with Workflow

/phx:plan {feature}  <-- YOU ARE HERE
       |
   /phx:plan --existing (optional enhancement)
       |
   ASK USER -> /phx:work .claude/plans/{feature}/plan.md
       |
/phx:review → /phx:compound

Notes

• Plans saved to `.claude/plans/{slug}/plan.md`
• Research reports in `.claude/plans/{slug}/research/` can be deleted after

CRITICAL: After Writing the Plan

**STOP. Do NOT proceed to implementation.**

After writing `.claude/plans/{slug}/plan.md`:

1. Summarize: task count, phases, key decisions 2. Use `AskUserQuestion` with options:

• "Start in fresh session" (recommended for 5+ tasks)
• "Get a briefing" (`/phx:brief` — interactive walkthrough)
• "Start here"
• "Review or adjust the plan"

3. Wait for user response. Never auto-start work.

**When user selects "Start in fresh session"**, print:

1. Run `/new` to start a fresh session
2. Then run one of:
   /phx:work .claude/plans/{slug}/plan.md
   /phx:full .claude/plans/{slug}/plan.md  (includes review + compound)

This is Iron Law #1. Violating it wastes user context.

References (DO NOT read — for human reference only)

• `${CL