Comet Phase 3: Plan and Build (Build)

Prerequisites

• Design Doc has been created (Phase 2 complete)
• Active change exists

Steps

0. Entry State Verification (Entry Check)

Execute entry verification:

COMET_ENV="${COMET_ENV:-$(find . "$HOME"/.*/skills "$HOME/.config" "$HOME/.gemini" -path '*/comet/scripts/comet-env.sh' -type f -print -quit 2>/dev/null)}"
if [ -z "$COMET_ENV" ]; then
  echo "ERROR: comet-env.sh not found. Ensure the comet skill is installed." >&2
  return 1
fi
. "$COMET_ENV"
"$COMET_BASH" "$COMET_STATE" check <name> build

Proceed to Step 1 after verification passes. The script outputs specific failure reasons when verification fails.

Idempotency: All build phase operations can be safely re-executed. Read .comet.yaml phase field to confirm still in build, read plan header base-ref, then use grep -n '\- \[ \]' tasks.md | head -1 to find the first unchecked task. Already-committed tasks must not be re-committed.

1. Create Plan (Subagent Offload)

Create the implementation plan through a subagent, avoiding planning skill occupying main session context. Plan files and execution feedback must use the language of the user request that triggered this workflow.

Subagent instructions:

You are an implementation planning expert. Create an implementation plan based on the following inputs:

1. Immediately execute: Use the Skill tool to load the Superpowers writing-plans skill. Skipping this step is prohibited. After the skill loads, ARGUMENTS must include: Language: Use the language of the user request that triggered this workflow
2. Read the Design Doc (technical design document under docs/superpowers/specs/)
3. Read openspec/changes/<name>/tasks.md (task boundaries)
4. Follow the skill's guidance to create the plan