subagent-development

name	subagent-development
description	Use when executing implementation plans with independent tasks in the current session. Dispatch a fresh subagent per task, with two-stage review after each — spec compliance review first, then code quality review. Keeps context clean and quality high.
available	coding

Subagent-Driven Development

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

Core principle: Fresh subagent per task + two-stage review (spec then quality) = high quality, fast iteration

When to Use

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

Key properties:

• Fresh subagent per task (no context pollution)
• Two-stage review after each task: spec compliance first, then code quality
• Faster iteration (no human-in-loop between tasks)

The Process

digraph process {
    rankdir=TB;

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

    "Read plan, extract all tasks with full text, note context, create todo" [shape=box];
    "More tasks remain?" [shape=diamond];
    "Dispatch final code reviewer subagent for entire implementation" [shape=box];
    "Done" [shape=box];

    "Read plan, extract all tasks with full text, note context, create todo" -> "Dispatch implementer subagent";
    "Dispatch implementer subagent" -> "Implementer subagent asks questions?";
    "Implementer subagent asks questions?" -> "Answer questions, provide context" [label="yes"];
    "Answer questions, provide context" -> "Dispatch implementer subagent";
    "Implementer subagent asks questions?" -> "Implementer subagent implements, tests, commits, self-reviews" [label="no"];
    "Implementer subagent implements, tests, commits, self-reviews" -> "Dispatch spec reviewer subagent";
    "Dispatch spec reviewer subagent" -> "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" -> "Dispatch spec reviewer subagent" [label="re-review"];
    "Spec reviewer subagent confirms code matches spec?" -> "Dispatch code quality reviewer subagent" [label="yes"];
    "Dispatch code quality reviewer subagent" -> "Code quality reviewer subagent approves?";
    "Code quality reviewer subagent approves?" -> "Implementer subagent fixes quality issues" [label="no"];
    "Implementer subagent fixes quality issues" -> "Dispatch code quality reviewer subagent" [label="re-review"];
    "Code quality reviewer subagent approves?" -> "Mark task complete" [label="yes"];
    "Mark task complete" -> "More tasks remain?";
    "More tasks remain?" -> "Dispatch implementer subagent" [label="yes"];
    "More tasks remain?" -> "Dispatch final code reviewer subagent for entire implementation" [label="no"];
    "Dispatch final code reviewer subagent for entire implementation" -> "Done";
}

Subagent Roles

Three Lua agents, dispatched via agent:

1. Implementer — agent(action: "start", name: "coding-implementer", prompt: "<full task text + context>") Implements a single task. Follows TDD, commits, self-reviews. May ask questions before starting.
2. Spec reviewer — agent(action: "start", name: "coding-spec-reviewer", prompt: "<spec text>") Checks that the implementation matches the spec exactly. Reports missing requirements and anything extra that was not requested.
3. Code quality reviewer — agent(action: "start", name: "coding-quality-reviewer", prompt: "<scope>") Reviews code quality only (after spec compliance is confirmed). Checks style, structure, test coverage, naming, etc.

After all tasks, dispatch the final reviewer: agent(action: "start", name: "coding-reviewer", prompt: "<overall scope>")

Step-by-Step

1. Read the plan once. Extract all tasks with full text and context. Do not make subagents read the plan file — provide the full text directly.
2. Create a todo. Use todo(action: "plan", ...) with all tasks from the plan.
3. Per task: a. Dispatch implementer subagent with full task text + scene-setting context. b. If the implementer asks questions, answer clearly and completely. Provide additional context if needed. Do not rush them into implementation. c. Implementer implements, writes tests, commits, and self-reviews. d. Dispatch spec reviewer subagent. If issues found, implementer fixes and spec reviewer reviews again. Repeat until approved. e. Dispatch code quality reviewer subagent. If issues found, implementer fixes and code quality reviewer reviews again. Repeat until approved. f. Mark task complete in the todo.
4. After all tasks: Dispatch the coding-reviewer agent for the entire implementation.
5. Wrap up using the finishing-a-development-branch workflow.

Example Workflow

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

[Read plan file once: docs/plans/feature-plan.md]
[Extract all 5 tasks with full text and context]
[Create todo with all tasks]

Task 1: Hook installation script

[Get Task 1 text and context (already extracted)]
[Dispatch implementation subagent with full task text + context]

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

You: "User level (~/.config/ghost/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

[Dispatch spec compliance reviewer]
Spec reviewer: Spec compliant - all requirements met, nothing extra

[Dispatch code quality reviewer]
Code reviewer: Strengths: Good test coverage, clean. Issues: None. Approved.

[Mark Task 1 complete]

Task 2: Recovery modes

[Get Task 2 text and context (already extracted)]
[Dispatch implementation subagent with full task text + context]

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

[Dispatch spec compliance 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

[Dispatch code quality reviewer]
Code reviewer: Strengths: Solid. Issues (Important): Magic number (100)

[Implementer fixes]
Implementer: Extracted PROGRESS_INTERVAL constant

[Code reviewer reviews again]
Code reviewer: Approved

[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 OPERATOR 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 approved (wrong order)
• Move to next task while either review has open 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)

Related

• Subagents follow TDD (test-driven development) for each task
• Use the finishing-a-development-branch workflow after all tasks are complete
• Prompt templates for reference: Read the implementer-prompt.md, spec-reviewer-prompt.md, and code-quality-reviewer-prompt.md extras