Comet Build

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

Plan requirements:

• Save to docs/superpowers/plans/YYYY-MM-DD-<feature>.md
• Reference design document, break down into executable tasks
• Plan file header must contain associated metadata:

---
change: <openspec-change-name>
design-doc: docs/superpowers/specs/YYYY-MM-DD-<topic>-design.md
base-ref: <git rev-parse HEAD before implementation>
---

base-ref is used during verification to measure committed changes across the full implementation range. Record the current commit when creating the plan:

git rev-parse HEAD

Write the plan to file, then return the file path.

Execute subagent: Use the current platform's subagent dispatch mechanism to send the above task.

After the subagent completes:

• If a valid file path is returned and the file exists, record it as the plan
• If the subagent fails or returns an invalid path, fall back to loading the Superpowers writing-plans skill inline in the main session (degraded fallback)

2. Update Plan Status and Provide Plan-Ready Pause Point

Record plan path:

"$COMET_BASH" "$COMET_STATE" set <name> plan docs/superpowers/plans/YYYY-MM-DD-feature.md

No manual phase update needed — guard auto-transitions when exit conditions are met.

After the plan is recorded, immediately provide a new user decision point:

This is a user decision point. Must follow the comet/reference/decision-point.md protocol to pause and wait for the user to explicitly choose. Must not auto-continue and must not write the pause into build_mode.

When the user chooses to continue:

"$COMET_BASH" "$COMET_STATE" set <name> build_pause null

When the user chooses to pause:

"$COMET_BASH" "$COMET_STATE" set <name> build_pause plan-ready

After setting build_pause: plan-ready, stop the current invocation. Do not choose isolation or build_mode, and do not load an execution skill.

3. Select Workflow Configuration

If resuming with build_pause: plan-ready and the plan file exists, do not rerun writing-plans. First tell the user the workflow is stopped at the plan-ready pause point; after the user confirms continuing, set:

"$COMET_BASH" "$COMET_STATE" set <name> build_pause null

Then continue this step to choose workspace isolation and execution method.

Plan has been written to the current branch. Before starting execution, ask the user to choose both workspace isolation and execution method in a single interaction:

Workspace Isolation:

Recommendation rules:

• Change involves ≤ 3 files → Recommend A
• Need parallel development, current branch has uncommitted work → Recommend B

Execution Method:

Execution method recommendation rules:

• Task count ≥ 3 → Recommend A
• Task count ≤ 2 and no cross-module dependencies → Recommend B
• From hotfix path → Recommend B

This is a user decision point. Must follow the comet/reference/decision-point.md protocol to pause and wait for the user to explicitly choose isolation method, execution method, and TDD mode. Must not choose branch or worktree based on recommendation rules, and must not choose the execution method or TDD mode based on recommendation rules. Recommendation rules are for suggestion only, not a substitute for user confirmation.

After user selection, update isolation, execution method, and TDD mode fields:

"$COMET_BASH" "$COMET_STATE" set <name> isolation <branch|worktree>

• If the user chooses executing-plans: run "$COMET_BASH" "$COMET_STATE" set <name> subagent_dispatch null, then run "$COMET_BASH" "$COMET_STATE" set <name> build_mode executing-plans
• If the user chooses subagent-driven-development: first confirm the current platform has real background subagent / Task / multi-agent dispatch capability; after confirming, run "$COMET_BASH" "$COMET_STATE" set <name> subagent_dispatch confirmed, then run "$COMET_BASH" "$COMET_STATE" set <name> build_mode subagent-driven-development
• If real background dispatch capability cannot be confirmed, must not write build_mode: subagent-driven-development; must pause and wait for the user to choose executing-plans instead

TDD Mode:

Run "$COMET_BASH" "$COMET_STATE" set <name> tdd_mode <tdd|direct>

isolation is a script-enforced hard constraint. Full workflow init may temporarily leave it as null, but only before this step. If it remains null, both the build → verify guard and comet-state transition build-complete will fail.

subagent_dispatch is a script-enforced hard constraint. build_mode: subagent-driven-development requires subagent_dispatch: confirmed before leaving the build phase, otherwise both comet-guard.sh build --apply and comet-state transition build-complete will fail.

tdd_mode is a script-enforced hard constraint. Full workflow must have tdd_mode selected as tdd or direct before leaving the build phase, otherwise both comet-guard.sh build --apply and comet-state transition build-complete will fail.

build_mode defaults to direct only for hotfix/tweak presets. Full workflow must not default to direct. Use it only when the user explicitly asks to bypass the plan execution skills and you record an explicit override:

"$COMET_BASH" "$COMET_STATE" set <name> direct_override true
"$COMET_BASH" "$COMET_STATE" set <name> build_mode direct

Without direct_override: true, build_mode=direct in full workflow is blocked by both guard and state transition.

Execute isolation:

• branch: Recommend a branch name based on the workflow type and current date, then let the user confirm or input a custom name. This is a user decision point — must use the current platform's available user input/confirmation mechanism to pause and wait for the user to explicitly confirm or override the branch name. Must not skip this step and create the branch directly.

  Branch naming convention:

  • Read the workflow field from .comet.yaml to determine the prefix
  • workflow: full → recommend feature/YYYYMMDD/<change-name>
  • workflow: hotfix → recommend hotfix/YYYYMMDD/<change-name>
  • workflow: tweak → recommend tweak/YYYYMMDD/<change-name>
  • Date is derived from date +%Y%m%d at runtime

  Example: if change name is fix-login-bug and today is 2026-06-09, recommend feature/20260609/fix-login-bug

  After the user confirms or provides a custom branch name, run git checkout -b <branch-name>, subsequent work on the new branch.

• worktree: Must use the Skill tool to load the Superpowers using-git-worktrees skill to create isolated workspace. Do not bypass this skill with plain shell commands or native tools; if the skill is unavailable, stop the process and prompt to install or enable Superpowers skills.

After creating isolation, confirm plan file is accessible (naturally accessible with branch method; for worktree method, confirm plan has been committed). If the plan file has not been committed under worktree mode, commit it first before creating the worktree:

git add docs/superpowers/plans/YYYY-MM-DD-feature.md
git commit -m "chore: add implementation plan"

Execute plan: Must handle execution according to the actual runtime of build_mode.

• build_mode: executing-plans: Immediately execute: Use the Skill tool to load the Superpowers executing-plans skill. Skipping this step is prohibited. If the skill is unavailable, stop the process and prompt to install or enable the corresponding skill; do not substitute with normal conversation. After the skill loads, ARGUMENTS must include the same Language constraint as Step 1: Language: Use the language of the user request that triggered this workflow. Execute according to plan.
• build_mode: subagent-driven-development: The main session only coordinates and must not write implementation code directly. Immediately execute: Use the Skill tool to load the Superpowers subagent-driven-development skill. After the skill loads, read comet/reference/subagent-dispatch.md for Comet-specific extensions (real background dispatch, task isolation, checkoff verification, TDD constraints, continuous execution, context recovery) and apply them alongside the skill's workflow. If they conflict, the more specific Comet extensions take precedence.
• If the current platform has no real background agent dispatch capability, must pause and wait for the user to choose main window execution instead. After the user chooses, must run "$COMET_BASH" "$COMET_STATE" set <name> build_mode executing-plans, then follow the build_mode: executing-plans branch to load the Superpowers executing-plans skill. Must not continue executing tasks before the user explicitly chooses.

TDD Mode Execution Constraints:

If tdd_mode: tdd:

• build_mode: executing-plans: After loading the execution skill and before executing the first task, Immediately execute: Use the Skill tool to load the Superpowers test-driven-development skill once. Skipping this step is prohibited. After the skill loads, start from the first unchecked task and follow the loaded TDD Red-Green-Refactor cycle for each task. Must not skip the failing test verification phase. Do not reload this skill for subsequent tasks; follow the already-loaded flow. If resuming after context compaction, re-run this step to load the TDD skill once, then continue from the first unchecked task.
• build_mode: subagent-driven-development: The main session does not load the TDD skill. TDD constraints and evidence thresholds are defined in comet/reference/subagent-dispatch.md; every background implementer and fix agent must use the Skill tool to load the Superpowers test-driven-development skill and follow the Comet-injected TDD hard constraint.

If tdd_mode: direct: Follow normal flow, no enforced TDD.

executing-plans review gate:

When build_mode is executing-plans, after all planned tasks are complete and before running the build → verify phase guard, must use the Skill tool to load the Superpowers requesting-code-review skill and request code review at least once.

Requirements:

• the requesting-code-review skill must be loaded before "$COMET_BASH" "$COMET_GUARD" <change-name> build --apply
• if requesting-code-review skill is unavailable, skip the review gate but must record <!-- review skipped: skill unavailable --> in tasks.md, then continue guard transition
• CRITICAL review findings (security vulnerabilities, data loss risk, build/test failures) must be fixed first and must not be carried into verify
• if non-CRITICAL review findings are accepted, record the acceptance reason and impact scope in tasks.md, the commit body, a verification report draft, or another durable artifact

3b. In-Execution Debugging (Debug Gate)

During task execution, whenever a crash, unexpected behavior, test failure, or build failure appears while running the program, tests, build, or manual verification, must use the Skill tool to load the Superpowers systematic-debugging skill. Before root-cause investigation is complete, must not propose or implement source-code fixes.

For specific investigation, minimal failing test, fix verification, and keeping the current change verification loop, follow comet/reference/debug-gate.md.

4. Spec Incremental Updates

When the initial spec is found incomplete during implementation, handle by scale:

50% Threshold Determination: Using initial task count in tasks.md as baseline, if new tasks exceed half of that total, it's considered outside original plan scope, must follow the comet/reference/decision-point.md protocol to pause and wait for the user to decide whether to split into a new change.

When creating an independent change, must invoke /comet-open, not /opsx:new directly. /comet-open creates both OpenSpec artifacts and .comet.yaml, preventing the new change from leaving the Comet state machine.

User choices must include:

• "Split into new change" — create independent change via /comet-open
• "Continue in current change" — record scope-expansion decision, update tasks.md and delta spec, then continue

Principles:

• Delta spec is a living document, can be modified at any time during this phase
• Each update should be committed with commit message explaining the change reason
• Do not sync to main spec in advance, sync uniformly during archiving
• For small-scale incremental direct delta spec edits, note in commit message to facilitate design doc drift assessment during archiving

5. Context Management

Build is the longest phase and may span many tasks. To support resume after context compaction:

• After each task: complete acceptance per the current execution branch before checking off and committing. subagent-driven-development must wait for both reviews to pass and perform targeted verification by unique task text. Use grep -c '\- \[ \]' tasks.md to check remaining unchecked count; no need to re-read the entire file
• Context compression recovery: Follow comet/reference/context-recovery.md with phase set to build.
• User manual-change resume: handle uncommitted changes through comet/reference/dirty-worktree.md. That protocol defines checks, attribution, and prohibitions. Build-specific handling:
  1. After attribution, if the diff implies plan or spec changes, handle it through Step 4 "Spec Incremental Updates"
• Long task split: if a single task exceeds 200 lines of code changes, consider splitting it into multiple subtasks and commits

Exit Conditions

• All tasks.md checked
• Code committed
• Project-specific build/tests explicitly run and pass; do not rely only on guard auto-detection
• isolation has been written as branch or worktree
• build_mode has been written as subagent-driven-development, executing-plans, or direct with explicit override; if subagent-driven-development, subagent_dispatch must be confirmed
• tdd_mode has been written as tdd or direct
• If build_mode is executing-plans, the Skill tool has been used to load the Superpowers requesting-code-review skill and request code review at least once, and CRITICAL review findings have been fixed or acceptance rationale for non-CRITICAL review findings has been recorded
• Phase guard: Run "$COMET_BASH" "$COMET_GUARD" <change-name> build --apply; after all PASS, state advances to phase: verify

Guard reads project command configuration first:

build_command: <build command>
verify_command: <verify command>

Configuration can live in the change .comet.yaml, or in repo-root .comet.yaml / comet.yaml / .comet.yml / comet.yml. Only when no command is configured does guard fall back to npm run build, Maven, or Cargo auto-detection. When a command fails, guard prints the command output as evidence for debugging.

Before exit, run guard to auto-transition:

"$COMET_BASH" "$COMET_GUARD" <change-name> build --apply

State file is automatically updated to phase: verify, verify_result: pending.

Automatic Handoff to Next Phase

Follow comet/reference/auto-transition.md. Key command:

"$COMET_BASH" "$COMET_STATE" next <change-name>

• NEXT: auto → invoke the skill pointed to by SKILL to enter the next phase
• NEXT: manual → do not invoke the next skill; prompt user to run /<SKILL> manually
• NEXT: done → workflow is complete, no further action needed