feature_dev

feature_dev is a skill for Claude Code, Codex from Aquifer-sea/pattern8. It costs 23 tokens per session (317 once invoked), scanned A, original, MIT.

A structured feature-development process that moves from requirements to design, implementation, and self-testing.

In plain words
What is it for?
Use it to clarify requirements, design an implementation, produce code and tests, record integration notes, and review the work for security and backward compatibility.
Why use it?
It gives feature work a repeatable checklist and requires the result to match acceptance criteria, include tests, and remain compatible with existing code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to clarify requirements, design an implementation, produce code and tests…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aquifer-sea/pattern8/feature_dev
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 Aquifer-sea/pattern8 --skill feature_dev
Clone the repo
git clone --depth 1 https://github.com/Aquifer-sea/pattern8

Made for: Claude Code, Codex.

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 feature_dev

README.md
[![agentmods](https://agentmods.dev/badge/skills/aquifer-sea/pattern8/feature_dev.svg)](https://agentmods.dev/skills/aquifer-sea/pattern8/feature_dev)
Your own site
<a href="https://agentmods.dev/skills/aquifer-sea/pattern8/feature_dev"><img src="https://agentmods.dev/badge/skills/aquifer-sea/pattern8/feature_dev.svg" alt="Measured on agentmods" height="20"></a>
Per session 23 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 317 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.
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 $0.00023 $0.00317
Opus 5 $0.00012 $0.00159
Sonnet 5 $0.00005 $0.00063
Haiku 4.5 $0.00002 $0.00032

Measured 7d ago against content hash a834b12ebdef, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

feature_dev 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 7d 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.

skills/feature_dev/SKILL.md · 45 lines

What it actually says

Feature Development

Constrains the Agent to follow "understand requirements → technical design → write code → self-test" structured process.

Step 1: Inversion (Requirements Alignment)

Before starting development, you must check every item in assets/checklist.yaml.

Step 2: Generator (Generate Development Plan + Code from Template)

Your output must strictly follow the format in assets/template.yaml. Must include: requirement understanding, technical design, implementation code, test code, integration notes.

Step 3: Tool Wrapper (Security Fence)

Commands executed during development must be checked against references/security.yaml. Do not introduce dependencies with known vulnerabilities or bypass authentication mechanisms.

Step 4: Reviewer (Self-Audit Loop)

Audit your development output against references/guidelines.yaml. Key checks: does it match acceptance criteria? Are there tests? Is it backward compatible? Roll back and regenerate if non-compliant, up to 3 retries.

Files

What ships with it

4 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. 7d ago First seen · 45 lines · 23 tokens per session scan A a834b12ebdef

Subscribe to this mod's changes

feature_dev is a skill published in the GitHub repository Aquifer-sea/pattern8 (49 stars, last pushed 5mo ago), licensed MIT. It adds 23 tokens to every session and 317 once invoked, about $0.0001 per session on Opus 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 2026-08-30.

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