planner-elaborate-phase

name	planner-elaborate-phase
categories	["planner"]
description	Elaborate a single phase into a full result, parallel-safe — receives plan snapshot + target phase ID
hooks	{"PreToolUse":[{"matcher":"*","hooks":[{"type":"command","command":"echo '[SKILL: planner-elaborate-phase] Elaborating phase...'","once":true}]}]}

planner-elaborate-phase

Standalone parallel worker for Phase Pass 1. Each instance receives the full plan snapshot (each phase in condensed form) and a target phase ID. It explores the codebase independently and writes a single elaborated phase result. No dependency on check_remaining or any shared state machine.

When to Use

• Launched in parallel by the L2 orchestrator (planner recipe, Issue 08)
• One instance per phase ID, all running simultaneously
• Also usable standalone for manual single-phase elaboration

Arguments

• $1 — Absolute path to plan_snapshot.json (every phase as a PhaseShort entry)
• $2 — Phase ID to elaborate (e.g., "P3")
• $3 — Absolute path to output directory (result written here)

Critical Constraints

NEVER:

• Write output outside $3/
• Read any *_result.json file from other phases (you have only the snapshot)
• Require or read a context file from check_remaining
• Communicate with other parallel worker instances
• Read {{AUTOSKILLIT_TEMP}} artifacts outside your designated input files and output directory
• Explore parent directories of your input paths (e.g., ls $(dirname $1)/..)
• Run subagents in the background (run_in_background: true is prohibited)

ALWAYS:

• Derive relationship_notes from snapshot context + codebase analysis, NOT from prior result files
• Write result to $3/{phase_id}_result.json (keep _result.json suffix — downstream consumers glob *_result.json)
• Emit: elab_result_path = <absolute path to {phase_id}_result.json>
• Include all PhaseElaborated fields in the result

Workflow

Step 1: Parse arguments and read snapshot

Read the plan snapshot at $1. It is a PlanDocument with a phases list of PhaseShort objects:

{
  "schema_version": 1,
  "task": "...",
  "source_dir": "...",
  "phases": [
    {"id": "P1", "name": "...", "goal": "...", "scope": [...], "ordering": 1},
    {"id": "P2", "name": "...", "goal": "...", "scope": [...], "ordering": 2},
    ...
  ]
}

Find the entry in phases where id == "$2" (the target phase). Note its ordering to understand which phases come before and after it.

After reading plan_snapshot.json, extract the task field. Every aspect of the elaborated phase — its technical_approach, scope, and assignments[] — must serve the stated task. Do not elaborate into work not requested by the task. Flag if the phase goal appears unrelated to the task.

Step 2: Launch parallel codebase exploration subagents

Spawn up to 5 simultaneous Explore subagents against the codebase in source_dir:

1. Affected files — Which files/modules fall within this phase's scope? Current state, imports, deviations from conventions.
2. Dependency analysis — What imports and consumes the affected modules? Full import graph.
3. Test coverage — Which tests cover the affected scope? Gaps in coverage?
4. Pattern discovery — What conventions and reusable utilities exist in this scope?
5. Cross-phase boundaries — Based on snapshot context (other phases' names/goals/scopes), where do likely dependencies or handoff points exist?

Step 3: Write phase result

Write to $3/{target_phase_id}_result.json matching PhaseElaborated:

{
  "id": "P3",
  "name": "...",
  "goal": "...",
  "scope": [...],
  "ordering": 3,
  "technical_approach": "...",
  "relationship_notes": "Depends on P1 (...name...) for ...; P5 (...name...) will consume ...",
  "assignments_preview": ["Assignment title 1", "Assignment title 2", ...]
}

For relationship_notes: use other phases' name, goal, and scope from the snapshot (not their result files) combined with codebase evidence to identify real dependencies.

Do NOT write phase_number or name_slug — the backend derives these at load time from ordering and name respectively.

Step 4: Emit output token

elab_result_path = <absolute path to $3/{id}_result.json>