subagent-driven-development

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

Subagent-Driven Development

Execute plan by dispatching fresh subagent per task, with two-stage review after each: spec compliance review first, then code quality review.

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 + two-stage review (spec then quality) = high quality, fast iteration

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

digraph when_to_use {
    "Have implementation plan?" [shape=diamond];
    "Tasks mostly independent?" [shape=diamond];
    "subagent-driven-development" [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?" -> "subagent-driven-development" [label="yes"];
    "Tasks mostly independent?" -> "Manual execution or brainstorm first" [label="no - tightly coupled"];
}

The Process

digraph process {
    rankdir=TB;

    subgraph cluster_per_task {
        label="Per Task";
        "invoke_subagent TypeName: implementer" [shape=box];
        "Implementer subagent asks questions?" [shape=diamond];
        "Answer questions, provide context" [shape=box];
        "Implementer subagent implements, tests, commits, self-reviews" [shape=box];
        "invoke_subagent TypeName: spec-reviewer" [shape=box];
        "Spec reviewer subagent confirms code matches spec?" [shape=diamond];
        "Implementer subagent fixes spec gaps" [shape=box];
        "invoke_subagent TypeName: code-reviewer" [shape=box];
        "Code quality reviewer subagent approves?" [shape=diamond];
        "Implementer subagent fixes quality issues" [shape=box];
        "Update task.md artifact" [shape=box];
    }

    "Read plan, extract all tasks, define subagent types, create task.md artifact" [shape=box];
    "More tasks remain?" [shape=diamond];
    "Dispatch final code reviewer subagent for entire implementation" [shape=box];
    "Use superpowers:finishing-a-development-branch" [shape=box style=filled fillcolor=lightgreen];

    "Read plan, extract all tasks, define subagent types, create task.md artifact" -> "invoke_subagent TypeName: implementer";
    "invoke_subagent TypeName: implementer" -> "Implementer subagent asks questions?";
    "Implementer subagent asks questions?" -> "Answer questions, provide context" [label="yes"];
    "Answer questions, provide context" -> "invoke_subagent TypeName: implementer";
    "Implementer subagent asks questions?" -> "Implementer subagent implements, tests, commits, self-reviews" [label="no"];
    "Implementer subagent implements, tests, commits, self-reviews" -> "invoke_subagent TypeName: spec-reviewer";
    "invoke_subagent TypeName: spec-reviewer" -> "Spec reviewer subagent confirms code matches spec?";
    "Spec reviewer subagent confirms code matches spec?" -> "Implementer subagent fixes spec gaps" [label="no"];
    "Implementer subagent fixes spec gaps" -> "invoke_subagent TypeName: spec-reviewer" [label="re-review"];
    "Spec reviewer subagent confirms code matches spec?" -> "invoke_subagent TypeName: code-reviewer" [label="yes"];
    "invoke_subagent TypeName: code-reviewer" -> "Code quality reviewer subagent approves?";
    "Code quality reviewer subagent approves?" -> "Implementer subagent fixes quality issues" [label="no"];
    "Implementer subagent fixes quality issues" -> "invoke_subagent TypeName: code-reviewer" [label="re-review"];
    "Code quality reviewer subagent approves?" -> "Update task.md artifact" [label="yes"];
    "Update task.md artifact" -> "More tasks remain?";
    "More tasks remain?" -> "invoke_subagent TypeName: implementer" [label="yes"];
    "More tasks remain?" -> "Dispatch final code reviewer subagent for entire implementation" [label="no"];
    "Dispatch final code reviewer subagent for entire implementation" -> "Use superpowers:finishing-a-development-branch";
}

Pre-Flight Plan Review

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.

Subagent Type Setup

At the start of plan execution, before dispatching any tasks, locate the absolute paths of the subagent-driven-development and requesting-code-review skill directories from the <skills> section of your prompt. Then, define all three subagent types:

1. define_subagent with name "implementer" — read implementer-prompt.md from the subagent-driven-development directory.
2. define_subagent with name "spec-reviewer" — read spec-reviewer-prompt.md from the subagent-driven-development directory.
3. define_subagent with name "code-reviewer" — read code-reviewer.md from the requesting-code-review directory.

This pays the prompt cost once. Every subsequent invoke_subagent with these types reuses the cached definition.

Workspace isolation per role:

Role	Workspace Mode	Why
Implementer	Workspace: "branch"	Needs isolated write access
Spec reviewer	Workspace: "inherit"	Read-only — only inspects code
Code reviewer	Workspace: "inherit"	Read-only — only inspects code

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, design, and review tasks: use the most capable available model.

Task complexity signals:

• 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

Handling Implementer Status

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

DONE: Proceed to spec compliance review.

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 user

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

Constructing Reviewer Prompts

Per-task reviews are task-scoped gates. The broad review happens once, at the final whole-branch review. When you fill a reviewer template:

• 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 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.
• 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 fresh subagent needs its task, the interfaces it touches, and the global constraints. Nothing else.
• Dispatch fix subagents for Critical and Important findings. Record Minor findings in the progress ledger as you go, and point the final whole-branch review at that list so it can triage which must be fixed before merge.
• Spec-compliance failures (from the spec-reviewer) are always blocking — the implementer must fix them before proceeding to code quality review. The severity triage above (Critical/Important/Minor) applies to the code-quality reviewer's findings.
• A finding labeled plan-mandated — or any finding that conflicts with what the plan's text requires — is the human's decision: 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.
• Every fix dispatch carries the implementer contract: the fix subagent re-runs the tests covering its change and reports the results. Name the covering test files in the dispatch — a one-line fix does not need the whole suite.
• If the final whole-branch review returns findings, dispatch ONE fix subagent with the complete findings list — not one fixer per finding.

Background Task Management

When implementers run long-running operations (builds, test suites, deployments), use manage_task instead of blocking:

For operations expected to take >30 seconds:

• Implementer should use run_command with a short WaitMsBeforeAsync (e.g., 500ms) to background it
• Use manage_task with status to check on completion when notified
• Don't poll in a loop — the system automatically notifies when tasks finish
• Use manage_task with kill to terminate stuck processes

When to background vs. wait:

digraph background_decision {
    "Operation expected >30s?" [shape=diamond];
    "Background with manage_task" [shape=box];
    "Wait synchronously" [shape=box];

    "Operation expected >30s?" -> "Background with manage_task" [label="yes"];
    "Operation expected >30s?" -> "Wait synchronously" [label="no"];
}

Agent Communication

Use send_message to communicate with running subagents:

Answering questions mid-flight:

• When an implementer asks a question while still running, use send_message with the implementer's conversation ID
• Don't re-dispatch a new subagent just to answer a question — the original implementer has context

Providing additional context:

• If you realize an implementer needs more information after dispatch, use send_message to send it
• The implementer receives it as a message and can incorporate it into their work

When to use send_message vs. re-dispatch:

• Subagent is still running and needs info → send_message
• Subagent reported NEEDS_CONTEXT and stopped → re-dispatch with context
• Subagent reported BLOCKED → assess blocker, possibly re-dispatch with different model

Timeout Protection

Use schedule as a safety net for complex tasks:

digraph timeout {
    "Dispatch implementer" [shape=box];
    "Set one-shot timer" [shape=box];
    "Timer fires?" [shape=diamond];
    "Check subagent status" [shape=box];
    "Subagent completes normally" [shape=box];
    "Timer cancelled automatically" [shape=box];

    "Dispatch implementer" -> "Set one-shot timer";
    "Set one-shot timer" -> "Timer fires?" [label="wait"];
    "Timer fires?" -> "Check subagent status" [label="yes - no response yet"];
    "Timer fires?" -> "Subagent completes normally" [label="no - response received"];
    "Subagent completes normally" -> "Timer cancelled automatically";
}

• Set a one-shot timer when dispatching implementers for complex tasks (5 minutes for standard tasks, 10 for complex ones)
• If the timer fires before the implementer responds, check status and intervene if needed
• The timer cancels automatically if the implementer responds first — no cleanup needed

For test suites expected to take 5+ minutes, use a recurring schedule instead of a one-shot timer:

schedule(CronExpression: "*/2 * * * *", MaxIterations: "5", Prompt: "Check implementer status for Task N")

Subagent Monitoring

Use manage_subagents to track running subagents:

• Action: "list" — check which subagents are still running before dispatching the next task
• Action: "kill" — terminate stuck subagents that haven't responded after timeout

Don't poll in a loop — the system notifies you when subagents complete. Use manage_subagents only when you need an explicit status check (e.g., before cleanup or when a timer fires).

Durable Progress

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: read .superpowers/sdd/progress.md from the repository root. Tasks listed there as complete are DONE — do not re-dispatch them; resume at the first task not marked complete.
• When a task's review comes back clean, append one line to the ledger in the same message as your other bookkeeping: Task N: complete (commits <base7>..<head7>, review clean).
• 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.

Prompt Templates

• implementer-prompt.md (located in the subagent-driven-development skill directory) — define_subagent definition (static system prompt + dynamic prompt template)
• spec-reviewer-prompt.md (located in the subagent-driven-development skill directory) — define_subagent definition (static system prompt + dynamic prompt template)
• code-quality-reviewer-prompt.md (located in the subagent-driven-development skill directory) — Delegates to code-reviewer type with extra review criteria
• code-reviewer.md (located in the requesting-code-review skill directory) — define_subagent definition (static system prompt + dynamic prompt template)

Example Workflow

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

[Read plan file once: docs/superpowers/plans/feature-plan.md]
[Extract all 5 tasks with full text and context]
[define_subagent "implementer" — static system prompt from implementer-prompt.md]
[define_subagent "spec-reviewer" — static system prompt from spec-reviewer-prompt.md]
[define_subagent "code-reviewer" — static system prompt from code-reviewer.md]
[Create task.md artifact with all tasks]

Task 1: Hook installation script

[Get Task 1 text and context (already extracted)]
[invoke_subagent TypeName: "implementer" with task text + context in Prompt]

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

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

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

[invoke_subagent TypeName: "spec-reviewer"]
Spec reviewer: ✅ Spec compliant - all requirements met, nothing extra

[invoke_subagent TypeName: "code-reviewer"]
Code reviewer: Strengths: Good test coverage, clean. Issues: None. Approved.

[Update task.md: mark Task 1 complete]

Task 2: Recovery modes

[Get Task 2 text and context (already extracted)]
[invoke_subagent TypeName: "implementer" with task text + context in Prompt]

Implementer: [No questions, proceeds]
Implementer:
  - Added verify/repair modes
  - 8/8 tests passing
  - Self-review: All good
  - Committed

[invoke_subagent TypeName: "spec-reviewer"]
Spec reviewer: ❌ Issues:
  - Missing: Progress reporting (spec says "report every 100 items")
  - Extra: Added --json flag (not requested)

[Implementer fixes issues]
Implementer: Removed --json flag, added progress reporting

[Spec reviewer reviews again]
Spec reviewer: ✅ Spec compliant now

[invoke_subagent TypeName: "code-reviewer"]
Code reviewer: Strengths: Solid. Issues (Important): Magic number (100)

[Implementer fixes]
Implementer: Extracted PROGRESS_INTERVAL constant

[Code reviewer reviews again]
Code reviewer: ✅ Approved

[Update task.md: mark Task 2 complete]

...

[After all tasks]
[Dispatch final code-reviewer]
Final reviewer: All requirements met, ready to merge

Done!

Advantages

vs. Manual execution:

• Subagents follow TDD naturally
• Fresh context per task (no confusion)
• Parallel-safe (subagents don't interfere)
• Subagent can ask questions (before AND during work)

Efficiency gains:

• No file reading overhead (controller provides full text)
• Controller curates exactly what context is needed
• Subagent gets complete information upfront
• Questions surfaced before work begins (not after)

Quality gates:

• Self-review catches issues before handoff
• Two-stage review: spec compliance, then code quality
• Review loops ensure fixes actually work
• Spec compliance prevents over/under-building
• Code quality ensures implementation is well-built

Cost:

• More subagent invocations (implementer + 2 reviewers per task)
• Controller does more prep work (extracting all tasks upfront)
• Review loops add iterations
• But catches issues early (cheaper than debugging later)

Red Flags

Never:

• Start implementation on main/master branch without explicit user consent
• Skip reviews (spec compliance OR code quality)
• Proceed with unfixed issues
• Dispatch multiple implementation subagents in parallel (conflicts)
• Make subagent read plan file (provide full text instead)
• Skip scene-setting context (subagent needs to understand where task fits)
• Ignore subagent questions (answer before letting them proceed)
• Accept "close enough" on spec compliance (spec reviewer found issues = not done)
• Skip review loops (reviewer found issues = implementer fixes = review again)
• Let implementer self-review replace actual review (both are needed)
• Start code quality review before spec compliance is ✅ (wrong order)
• Move to next task while either review has open Critical/Important issues

If subagent asks questions:

• Answer clearly and completely
• Provide additional context if needed
• Don't rush them into implementation

If reviewer finds issues:

• Implementer (same subagent) fixes them
• Reviewer reviews again
• Repeat until approved
• Don't skip the re-review

If subagent fails task:

• Dispatch fix subagent with specific instructions
• Don't try to fix manually (context pollution)

Integration

Required workflow skills:

• superpowers:using-git-worktrees - Ensures isolated workspace (creates one or verifies existing)
• superpowers:writing-plans - Creates the plan this skill executes
• superpowers:requesting-code-review - Code review template for reviewer subagents
• superpowers:finishing-a-development-branch - Complete development after all tasks

Subagents should use:

• superpowers:test-driven-development - Subagents follow TDD for each task