superpowers/skills/subagent-driven-development/SKILL.md

---
name: subagent-driven-development
description: Use when executing implementation plans with independent tasks in the current session
---

# Subagent-Driven Development

Execute plan by dispatching a fresh implementer subagent per task, a task review (spec compliance + code quality) after each, and a broad whole-branch review at the end.

**Why subagents:** You delegate tasks to specialized agents with isolated context. By precisely crafting their instructions and context, you ensure they stay focused and succeed at their task. They should never inherit your session's context or history — you construct exactly what they need. This also preserves your own context for coordination work.

**Core principle:** Fresh subagent per task + task review (spec + quality) + broad final review = high quality, fast iteration

**Narration:** between tool calls, narrate at most one short line — the
ledger and the tool results carry the record.

**Continuous execution:** Do not pause to check in with your human partner between tasks. Execute all tasks from the plan without stopping. The only reasons to stop are: BLOCKED status you cannot resolve, ambiguity that genuinely prevents progress, or all tasks complete. "Should I continue?" prompts and progress summaries waste their time — they asked you to execute the plan, so execute it.

## When to Use

```dot
digraph when_to_use {
    "Have implementation plan?" [shape=diamond];
    "Tasks mostly independent?" [shape=diamond];
    "Stay in this session?" [shape=diamond];
    "subagent-driven-development" [shape=box];
    "executing-plans" [shape=box];
    "Manual execution or brainstorm first" [shape=box];

    "Have implementation plan?" -> "Tasks mostly independent?" [label="yes"];
    "Have implementation plan?" -> "Manual execution or brainstorm first" [label="no"];
    "Tasks mostly independent?" -> "Stay in this session?" [label="yes"];
    "Tasks mostly independent?" -> "Manual execution or brainstorm first" [label="no - tightly coupled"];
    "Stay in this session?" -> "subagent-driven-development" [label="yes"];
    "Stay in this session?" -> "executing-plans" [label="no - parallel session"];
}
```

**vs. Executing Plans (parallel session):**
- Same session (no context switch)
- Fresh subagent per task (no context pollution)
- Review after each task (spec compliance + code quality), broad review at the end
- Faster iteration (no human-in-loop between tasks)

## The Process

```dot
digraph process {
    rankdir=TB;

    subgraph cluster_per_task {
        label="Per Task";
        "Dispatch implementer subagent (./implementer-prompt.md)" [shape=box];
        "Implementer asks questions?" [shape=diamond];
        "Answer questions, provide context" [shape=box];
        "Implementer implements, tests, commits, self-reviews" [shape=box];
        "Generate review package, dispatch task reviewer (./task-reviewer-prompt.md)" [shape=box];
        "Spec ✅ and quality approved?" [shape=diamond];
        "Finding conflicts with plan text?" [shape=diamond];
        "Ask human partner which governs" [shape=box];
        "Fix round R of 5: R≤3 resume implementer; R≥4 fresh implementer, more capable model" [shape=box];
        "Dispatch scoped re-review (./re-review-prompt.md)" [shape=box];
        "All findings addressed?" [shape=diamond];
        "R = 5?" [shape=diamond];
        "Adjudicate each open finding" [shape=box];
        "Any load-bearing finding?" [shape=diamond];
        "STOP: report BLOCKED to human partner" [shape=box];
        "Park findings in ledger with rulings" [shape=box];
        "Append completion to ledger, mark todo complete" [shape=box];
    }

    "Setup: worktree, ledger check, read plan, pre-flight review" [shape=box];
    "More tasks remain?" [shape=diamond];
    "Dispatch final code reviewer (../requesting-code-review/code-reviewer.md)" [shape=box];
    "Final findings? ONE fix dispatch, one scoped re-review, adjudicate residuals" [shape=box];
    "Use superpowers:finishing-a-development-branch" [shape=box style=filled fillcolor=lightgreen];

    "Setup: worktree, ledger check, read plan, pre-flight review" -> "Dispatch implementer subagent (./implementer-prompt.md)";
    "Dispatch implementer subagent (./implementer-prompt.md)" -> "Implementer asks questions?";
    "Implementer asks questions?" -> "Answer questions, provide context" [label="yes"];
    "Answer questions, provide context" -> "Implementer implements, tests, commits, self-reviews";
    "Implementer asks questions?" -> "Implementer implements, tests, commits, self-reviews" [label="no"];
    "Implementer implements, tests, commits, self-reviews" -> "Generate review package, dispatch task reviewer (./task-reviewer-prompt.md)";
    "Generate review package, dispatch task reviewer (./task-reviewer-prompt.md)" -> "Spec ✅ and quality approved?";
    "Spec ✅ and quality approved?" -> "Append completion to ledger, mark todo complete" [label="yes"];
    "Spec ✅ and quality approved?" -> "Finding conflicts with plan text?" [label="no"];
    "Finding conflicts with plan text?" -> "Ask human partner which governs" [label="yes"];
    "Ask human partner which governs" -> "Fix round R of 5: R≤3 resume implementer; R≥4 fresh implementer, more capable model";
    "Finding conflicts with plan text?" -> "Fix round R of 5: R≤3 resume implementer; R≥4 fresh implementer, more capable model" [label="no"];
    "Fix round R of 5: R≤3 resume implementer; R≥4 fresh implementer, more capable model" -> "Dispatch scoped re-review (./re-review-prompt.md)";
    "Dispatch scoped re-review (./re-review-prompt.md)" -> "All findings addressed?";
    "All findings addressed?" -> "Append completion to ledger, mark todo complete" [label="yes"];
    "All findings addressed?" -> "R = 5?" [label="no"];
    "R = 5?" -> "Fix round R of 5: R≤3 resume implementer; R≥4 fresh implementer, more capable model" [label="no - next round"];
    "R = 5?" -> "Adjudicate each open finding" [label="yes - breaker trips"];
    "Adjudicate each open finding" -> "Any load-bearing finding?";
    "Any load-bearing finding?" -> "STOP: report BLOCKED to human partner" [label="yes"];
    "Any load-bearing finding?" -> "Park findings in ledger with rulings" [label="no"];
    "Park findings in ledger with rulings" -> "Append completion to ledger, mark todo complete";
    "Append completion to ledger, mark todo complete" -> "More tasks remain?";
    "More tasks remain?" -> "Dispatch implementer subagent (./implementer-prompt.md)" [label="yes"];
    "More tasks remain?" -> "Dispatch final code reviewer (../requesting-code-review/code-reviewer.md)" [label="no"];
    "Dispatch final code reviewer (../requesting-code-review/code-reviewer.md)" -> "Final findings? ONE fix dispatch, one scoped re-review, adjudicate residuals";
    "Final findings? ONE fix dispatch, one scoped re-review, adjudicate residuals" -> "Use superpowers:finishing-a-development-branch";
}
```

## Setup

Ensure the work happens in an isolated workspace: use
superpowers:using-git-worktrees to create one or verify the existing one.
Never start implementation on a main/master branch without your human
partner's explicit consent.

Conversation memory does not survive compaction. In real sessions,
controllers that lost their place have re-dispatched entire completed task
sequences — the single most expensive failure observed. Track progress in
a ledger file, not only in todos.

- At skill start, check for a ledger:
  `cat "$(git rev-parse --show-toplevel)/.superpowers/sdd/progress.md"`. Tasks with
  a `Task <N>: complete` line are DONE — do not re-dispatch them; resume at
  the first task without one. A task whose last line is a fix round is
  mid-loop: resume the loop at the next round.
- The ledger is your recovery map: the commits it names exist in git even
  when your context no longer remembers creating them. After compaction,
  trust the ledger and `git log` over your own recollection.
- `git clean -fdx` will destroy the ledger (it's git-ignored scratch); if
  that happens, recover from `git log`.

Read the plan once, note its context and Global Constraints, and create a
todo per task.

Before dispatching Task 1, scan the plan once for conflicts:

- tasks that contradict each other or the plan's Global Constraints
- anything the plan explicitly mandates that the review rubric treats as a
  defect (a test that asserts nothing, verbatim duplication of a logic block)

Present everything you find to your human partner as one batched question —
each finding beside the plan text that mandates it, asking which governs —
before execution begins, not one interrupt per discovery mid-plan. If the
scan is clean, proceed without comment. The review loop remains the net for
conflicts that only emerge from implementation.

## Model Selection

Use the least powerful model that can handle each role to conserve cost and increase speed.

**Mechanical implementation tasks** (isolated functions, clear specs, 1-2 files): use a fast, cheap model. Most implementation tasks are mechanical when the plan is well-specified.

**Integration and judgment tasks** (multi-file coordination, pattern matching, debugging): use a standard model.

**Architecture and design tasks**: use the most capable available model.
The final whole-branch review is one of these — dispatch it on the most
capable available model, not the session default.

**Review tasks**: choose the model with the same judgment, scaled to the
diff's size, complexity, and risk. A small mechanical diff does not need the
most capable model; a subtle concurrency change does. Scoped re-reviews of
small fix diffs take a cheap-to-mid tier.

**Fix-loop escalation (rounds 4-5)**: use a model at least one tier above
the implementer that got stuck.

**Always specify the model explicitly when dispatching a subagent.** An
omitted model inherits your session's model — often the most capable and
most expensive — which silently defeats this section.

**Turn count beats token price.** Wall-clock and context cost scale with how
many turns a subagent takes, and the cheapest models routinely take 2-3× the
turns on multi-step work — costing more overall. Use a mid-tier model as the
floor for reviewers and for implementers working from prose descriptions.
When the task's plan text contains the complete code to write, the
implementation is transcription plus testing: use the cheapest tier for
that implementer. Single-file mechanical fixes also take the cheapest tier.

**Task complexity signals (implementation tasks):**
- Touches 1-2 files with a complete spec → cheap model
- Touches multiple files with integration concerns → standard model
- Requires design judgment or broad codebase understanding → most capable model

## The Task Loop

Everything you paste into a dispatch prompt — and everything a subagent
prints back — stays resident in your context for the rest of the session
and is re-read on every later turn. Hand artifacts over as files.

### 1. Dispatch the implementer

Record BASE (`git rev-parse HEAD`) before dispatching — the review package
and fix-round diffs need it.

- **Task brief:** before dispatching an implementer, run this skill's
  `scripts/task-brief PLAN_FILE N` — it extracts the task's full text to a
  uniquely named file and prints the path. Compose the dispatch so the
  brief stays the single source of
  requirements. Your dispatch should contain: (1) one line on where this
  task fits in the project; (2) the brief path, introduced as "read this
  first — it is your requirements, with the exact values to use verbatim";
  (3) interfaces and decisions from earlier tasks that the brief cannot
  know; (4) your resolution of any ambiguity you noticed in the brief;
  (5) the report-file path and report contract. Exact values (numbers,
  magic strings, signatures, test cases) appear only in the brief. Never
  make a subagent read the whole plan file.
- **Report file:** name the implementer's report file after the brief
  (brief `…/task-N-brief.md` → report `…/task-N-report.md`) and put it in
  the dispatch prompt. The implementer writes the full report there and
  returns only status, commits, a one-line test summary, and concerns.
- A dispatch prompt describes one task, not the session's history. Do not
  paste accumulated prior-task summaries ("state after Tasks 1-3") into
  later dispatches — a real session's dispatch hit 42k chars of which 99%
  was pasted history. A fresh subagent needs its task, the interfaces it
  touches, and the global constraints. Nothing else.
- If an earlier task parked a finding in the area this task touches, carry
  a pointer to that ledger entry in the dispatch.
- Record the implementer's agent identity from the dispatch result —
  fix-loop rounds 1-3 resume this agent.
- Never dispatch multiple implementation subagents in parallel (conflicts).

Template: [implementer-prompt.md](implementer-prompt.md)

### 2. Handle the report

Implementer subagents report one of four statuses. Handle each appropriately:

**DONE:** Generate the review package (`scripts/review-package BASE HEAD`, from this skill's directory — it prints the unique file path it wrote; BASE is the commit you recorded before dispatching the implementer — never `HEAD~1`, which silently drops all but the last commit of a multi-commit task), then dispatch the task reviewer with the printed path.

**DONE_WITH_CONCERNS:** The implementer completed the work but flagged doubts. Read the concerns before proceeding. If the concerns are about correctness or scope, address them before review. If they're observations (e.g., "this file is getting large"), note them and proceed to review.

**NEEDS_CONTEXT:** The implementer needs information that wasn't provided. Provide the missing context and re-dispatch.

**BLOCKED:** The implementer cannot complete the task. Assess the blocker:
1. If it's a context problem, provide more context and re-dispatch with the same model
2. If the task requires more reasoning, re-dispatch with a more capable model
3. If the task is too large, break it into smaller pieces
4. If the plan itself is wrong, escalate to the human

**Never** ignore an escalation or force the same model to retry without changes. If the implementer said it's stuck, something needs to change.

If the implementer asks questions — before starting or mid-task — answer
clearly and completely, provide additional context if needed, and don't
rush it into implementation.

### 3. Review the task

Per-task reviews are task-scoped gates. The broad review happens once, at the
final whole-branch review. Never skip the task review, and never accept a
report missing either verdict — spec compliance AND task quality are both
required. Implementer self-review never replaces the task review; both are
needed.

- Hand the reviewer its diff as a file: run this skill's
  `scripts/review-package BASE HEAD` and pass the reviewer the file path
  it prints (or, without bash: `git log --oneline`, `git diff --stat`,
  and `git diff -U10` for the range, redirected to one uniquely named
  file). The output never enters your own context, and the reviewer sees
  the commit list, stat summary, and full diff with context in one Read
  call. Use the BASE you recorded before dispatching the implementer —
  never `HEAD~1`, which silently truncates multi-commit tasks. Never
  dispatch a task reviewer without a diff file.
- **Reviewer inputs:** the task reviewer gets three paths — the same brief
  file, the report file, and the review package — plus the global
  constraints that bind the task.
- The global-constraints block you hand the reviewer is its attention
  lens. Copy the binding requirements verbatim from the plan's Global
  Constraints section or the spec: exact values, exact formats, and the
  stated relationships between components ("same layout as X", "matches
  Y"). The reviewer's template already carries the process rules (YAGNI,
  test hygiene, review method) — the constraints block is for what THIS
  project's spec demands.
- Do not add open-ended directives like "check all uses" or "run race tests
  if useful" without a concrete, task-specific reason
- Do not ask a reviewer to re-run tests the implementer already ran on the
  same code — the implementer's report carries the test evidence
- Do not pre-judge findings for the reviewer — never instruct a reviewer to
  ignore or not flag a specific issue. If you believe a finding would be a
  false positive, let the reviewer raise it and adjudicate it in the review
  loop. If the prompt you are writing contains "do not flag," "don't treat X
  as a defect," "at most Minor," or "the plan chose" — stop: you are
  pre-judging, usually to spare yourself a review loop.

The task reviewer may report "⚠️ Cannot verify from diff" items — requirements
that live in unchanged code or span tasks. These do not block the rest of the
review, but you must resolve each one yourself before marking the task
complete: you hold the plan and cross-task context the reviewer
lacks. If you confirm an item is a real gap, treat it as a failed spec
review — it enters the fix loop with the other findings.

Template: [task-reviewer-prompt.md](task-reviewer-prompt.md)

### 4. The fix loop

The loop triggers when the review reports spec ❌, any Critical or Important
finding, or a ⚠️ item you confirmed as a real gap.

Before the loop starts, two routes leave it immediately:

- Record Minor findings in the progress ledger as you go
  (`Task <N>: minor (deferred): <one-liner>`), and point the final
  whole-branch review at that list so it can triage which must be fixed
  before merge. A roll-up nobody reads is a silent discard. Minor findings
  never enter the loop.
- A finding labeled plan-mandated — or any finding that conflicts with
  what the plan's text requires — is the human's decision, like any plan
  contradiction: present the finding and the plan text, ask which governs.
  Do not dismiss the finding because the plan mandates it, and do not
  dispatch a fix that contradicts the plan without asking.

Everything else enters the loop. A fix round is one fix dispatch plus one
scoped re-review. Five rounds maximum per task:

**Rounds 1-3 — resume the original implementer.** Send it the open findings
verbatim. Its context is intact: it knows the task, the code, and its own
choices. If your harness cannot send another message to a live subagent,
dispatch a fresh implementer carrying the brief path, the report-file path,
and the findings — the report file is the persistent memory either way.

**Rounds 4-5 — dispatch a fresh implementer on a more capable model** (per
Model Selection), with the brief path, the report-file path, the open
findings, and this framing: "A prior implementer attempted this task
[N] times; you own it now. Read the report file for what was tried." A loop
that survives three resumes usually means the implementer cannot see its
own problem — fresh eyes and a capability bump in one move.

**Every round, either way:** the implementer fixes, re-runs the tests
covering the amended code, appends its fix report to the same report file,
and returns the short contract. Before re-dispatching the reviewer, confirm
the fix report contains the covering tests, the command run, and the
output; dispatch the re-review once all three are present. Name the
covering test files in the fix message — a one-line fix does not need the
whole suite.

**The re-review is scoped.** Run `scripts/review-package FIX_BASE HEAD`
where FIX_BASE is the head the previous review saw, and dispatch
[re-review-prompt.md](re-review-prompt.md) with the findings list, the
brief, the report file, and the printed diff path. The re-reviewer verdicts
each finding ADDRESSED or NOT ADDRESSED and flags new breakage in the fix
diff only. New Critical/Important breakage in the fix diff joins the open
findings list. Out-of-scope observations go to the ledger as deferred
minors — they never extend the loop.

**After each round,** append to the ledger:
`Task <N>: fix round <R>/5 (<X> addressed, <Y> open — <finding one-liners>; commits <a7>..<b7>)`

Never fix findings yourself in the controller session — your context stays
clean for coordination, and controller fixes skip review.

**The breaker.** When round 5's re-review still leaves findings open, stop
dispatching. Adjudicate each open finding yourself — you hold the plan and
the cross-task context the reviewer lacks:

- **The reviewer is wrong, or the point is contestable:** park it —
  `Task <N>: parked — <finding> — ruling: <why the code stands>`. The final
  review sees both sides.
- **Real, but nothing downstream builds on it:** park it the same way, with
  a ruling that says it's real and deferred.
- **Real and load-bearing** — a later task builds on it, or it reveals a
  plan defect: STOP. Append `Task <N>: BLOCKED — <reason>` and report to
  your human partner with the finding, the plan text it collides with, and
  the fix history. Parking a structural failure lets every dependent task
  build on it and hands the final review a problem it cannot fix either.

Adjudicate only at the cap. Adjudicating earlier to end a loop is
pre-judging with a different name. Every adjudication is a ledger entry —
a silent discard is forbidden.

### 5. Complete the task

When the review comes back clean — or every open finding is parked with a
ruling at the cap — append the completion line to the ledger in the same
message as your other bookkeeping:

- `Task <N>: complete (commits <base7>..<head7>, review clean)`
- `Task <N>: complete (commits <base7>..<head7>, <K> parked)` after a
  tripped breaker

Then mark the todo complete and move on. Never move to the next task while
the review has open Critical/Important issues that are neither fixed nor
parked-with-ruling at the cap.

## Final Review

The final whole-branch review gets a package too: run
`scripts/review-package MERGE_BASE HEAD` (MERGE_BASE = the commit the
branch started from, e.g. `git merge-base main HEAD`) and include the
printed path in the final review dispatch, so the final reviewer reads
one file instead of re-deriving the branch diff with git commands. Dispatch
on the most capable available model (see Model Selection), using
superpowers:requesting-code-review's
[code-reviewer.md](../requesting-code-review/code-reviewer.md). Point it at
the ledger's deferred-minor and parked lines so it can triage which must be
fixed before merge.

If the final whole-branch review returns findings, dispatch ONE fix subagent
with the complete findings list — not one fixer per finding.
Per-finding fixers each rebuild context and re-run suites; a real
session's final-review fix wave cost more than all its tasks combined.
Then run exactly one scoped re-review of the fix wave
(`scripts/review-package` over the fix range, [re-review-prompt.md](re-review-prompt.md)).
Adjudicate any residual findings as in the task loop's breaker: park with
rulings, or stop on load-bearing ones. There is no second fix wave —
residual load-bearing findings surface to your human partner when
finishing-a-development-branch presents the options.

## Finish

Use superpowers:finishing-a-development-branch.

## Common Rationalizations

| Excuse | Reality |
|--------|---------|
| "Close enough on spec compliance" | Reviewer found spec gaps = not done. Fix or hit the cap and adjudicate — those are the only exits. |
| "I'll fix it myself, dispatching is overhead" | Controller fixes pollute your context and skip review. Resume the implementer. |
| "One more round will converge" | Past the cap, rounds don't converge — the failure is structural. Adjudicate and route. |
| "The reviewer will just find something new anyway" | Scoped re-reviews verify fixes; they cannot wander. New findings on untouched code go to the ledger, not the loop. |
| "This finding is obviously wrong, I'll drop it" | You adjudicate only at the cap, and every ruling is a ledger entry. Silent discards are forbidden. |
| "The fix was small, skip the re-review" | Unreviewed fixes are how regressions land. Every round ends with a scoped re-review. |
| "Reviews slow the loop down" | The loop without reviews is just unverified churn. Reviews are the loop's brakes and steering. |
| "Ledger bookkeeping is overhead" | The ledger is what survives compaction. Controllers without one have re-dispatched entire completed task sequences. |

## Example Workflow

```
You: I'm using Subagent-Driven Development to execute this plan.

[Setup: worktree verified, no ledger found, read plan, created todos]

Task 1: Hook installation script

[Run task-brief for Task 1; dispatch implementer with brief + report paths + context]

Implementer: "Before I begin - should the hook be installed at user or system level?"

You: "User level (~/.config/superpowers/hooks/)"

Implementer: [Later]
  - Implemented install-hook command
  - Added tests, 5/5 passing
  - Self-review: Found I missed --force flag, added it
  - Committed

[Run review-package, dispatch task reviewer with the printed path]
Task reviewer: Spec ✅ - all requirements met, nothing extra.
  Strengths: Good test coverage, clean. Issues: None. Task quality: Approved.

[Ledger: Task 1: complete (commits a1b2c3d..d4e5f6a, review clean)]

Task 2: Recovery modes

[Run task-brief for Task 2; dispatch implementer with brief + report paths + context]

Implementer: [No questions]
  - Added verify/repair modes
  - 8/8 tests passing
  - Committed

[Run review-package, dispatch task reviewer with the printed path]
Task reviewer: Spec ❌:
  - Missing: Progress reporting (spec says "report every 100 items")
  Issues (Important): Magic number (100)

[Fix round 1: resume the implementer with both findings]
Implementer: Added progress reporting, extracted PROGRESS_INTERVAL constant.
  Re-ran test/recovery.test.js — 10/10 passing. Fix report appended.

[Run review-package FIX_BASE HEAD; dispatch scoped re-review]
Re-reviewer: Missing progress reporting — ADDRESSED (src/recovery.js:41).
  Magic number — ADDRESSED (src/recovery.js:7). New breakage: none.
  Verdict: all findings addressed.

[Ledger: Task 2: fix round 1/5 (2 addressed, 0 open; commits d4e5f6a..b7c8d9e)]
[Ledger: Task 2: complete (commits d4e5f6a..b7c8d9e, review clean)]

...

[After all tasks]
[Run review-package MERGE_BASE HEAD; dispatch final code-reviewer, most capable model]
Final reviewer: All requirements met. Deferred minors triaged: none block merge.

Done! Using superpowers:finishing-a-development-branch.
```