subagent-development

subagent-development is a skill for Claude Code from softspark/ai-toolkit. It costs 41 tokens per session (1,921 once invoked), scanned A, original, Apache-2.0.

A workflow for carrying out an implementation plan with a fresh coding agent for each task, followed by separate checks for requirements and code quality.

In plain words
What is it for?
Use it to execute multi-step plans with ordered implementation, specification review, and quality review gates.
Why use it?
It reduces confusion between tasks and catches both missing behaviour and structural problems before work is accepted.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions subagents; mentions Claude Code; mentions Codex.

Part of the ai-toolkit plugin — 115 skills, 44 agents, 14 hooks shipped together

Good fit Use it to execute multi-step plans with ordered implementation, specification review, and quality review gates.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/softspark/ai-toolkit/subagent-development
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add softspark/ai-toolkit --skill subagent-development
Clone the repo
git clone --depth 1 https://github.com/softspark/ai-toolkit

Made for: Claude Code.

Or install ai-toolkit, the plugin that ships this one along with the rest of its 115 skills, 44 agents, 14 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for subagent-development

README.md
[![agentmods](https://agentmods.dev/badge/skills/softspark/ai-toolkit/subagent-development/github.svg)](https://agentmods.dev/skills/softspark/ai-toolkit/subagent-development)
Your own site
<a href="https://agentmods.dev/skills/softspark/ai-toolkit/subagent-development"><img src="https://agentmods.dev/badge/skills/softspark/ai-toolkit/subagent-development/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for subagent-development

Your own site · 80×15
<a href="https://agentmods.dev/skills/softspark/ai-toolkit/subagent-development"><img src="https://agentmods.dev/badge/skills/softspark/ai-toolkit/subagent-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 41 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,921 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00041 $0.01921
Opus 5.5 $0.00016 $0.00768
Sonnet 5.5 $0.00008 $0.00384
Haiku 4.5 $0.00004 $0.00192

Measured 13d ago against content hash 9fc8d194339e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

subagent-development scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 13d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

app/skills/subagent-development/SKILL.md · 233 lines

How it starts

The opening of the file, as written. The whole thing — 233 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Subagent Development

$ARGUMENTS

Execute implementation plans by dispatching fresh subagents per task, then running a two-stage review gate: spec compliance first, code quality second. Fresh context per subagent prevents accumulated confusion. Two-stage review catches different failure modes: spec review catches wrong behavior, quality review catches bad structure.

Usage

/subagent-development [plan file or task description]

Why This Works

Property Benefit
Fresh subagent per task No accumulated context drift or confusion
Spec review first Catches wrong behavior before quality review wastes time on wrong code
Quality review second Catches structural issues after behavior is confirmed correct
Sequential tasks No merge conflicts, each task builds on verified previous work

Process Flow

Read plan
    |
    v
Extract ordered task list
    |
    v
For each task:
    |
    +---> [1] Dispatch IMPLEMENTER subagent
    |         |
    |         v
    |     Handle status (see Status Protocol)
    |         |
    |         v
    +---> [2] Dispatch SPEC REVIEWER subagent
    |         |
    |         v
    |     APPROVED? --no--> fix issues, re-review
    |         |
    |        yes
    |         |
    |         v
    +---> [3] Dispatch QUALITY REVIEWER subagent
    |         |
    |         v
    |     Critical issues? --yes--> fix, re-review
    |         |
    |         no
    |         v
    |     Mark task complete
    |
    v
Next task (or done)

Step 1 -- Read and Parse Plan

Read the plan file. Extract:

  1. Ordered task list -- each task with description, acceptance criteria, file scope
  2. Global constraints -- what must NOT change, architecture rules, shared conventions
  3. Dependencies -- which tasks depend on which (execute in dependency order)

Present the task list to the user. Wait for approval before proceeding.

Step 2 -- Execute Tasks Sequentially

Only in Claude Code, apply the model-routing-patterns skill when choosing executors or creating agent definitions. Delegate to codex:codex-rescue only when its plugin is installed, enabled and callable in this session. Otherwise use the installed native agents and their configured models. A context without the Agent tool returns the dispatch decision to its supervisor; it does not invent a tool or bypass the client. Preserve explicit user choices and verify actual completion before accepting a delegated result.

Read the full file on GitHub · 233 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 13d ago Changed · +10 lines 9fc8d194339e
  2. 22d ago Changed · -3 lines 0efaefdfd704
  3. 1mo ago First seen · 226 lines · 41 tokens per session scan A 4736c33e3b42

Subscribe to this mod's changes

subagent-development is a skill published in the GitHub repository softspark/ai-toolkit (180 stars, last pushed yesterday), licensed Apache-2.0. It adds 41 tokens to every session and 1,921 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.