feature-dev

A command that guides a software feature through planning, implementation, testing, and code review. Code review is the process of checking proposed changes for problems.

In plain words
What is it for?
Planning a feature, implementing it, testing it with TDD (writing tests as part of development), and reviewing the changes.
Why use it?
It breaks feature work into smaller phases so the plan, code, and checks are handled together.

Command

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.

agentmods
npx agentmods add commands/noah-sheldon/ai-dev-kit/feature-dev
Clone the repo
git clone --depth 1 https://github.com/noah-sheldon/ai-dev-kit
Per session 13 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 85 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00013 $0.00085
Opus 5 $0.00006 $0.00043
Sonnet 5 $0.00003 $0.00017
Haiku 4.5 $0.00001 $0.00009

Measured yesterday against content hash 67b0bf136a1e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 yesterday.

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.

commands/feature-dev.md · 18 lines

What it actually says

Feature Dev

Drive a feature from plan to implementation to review.

Delegate

Apply the planner, tdd-workflow, code-review skill.

Notes

  • Plan, implement, and verify the feature in small phases.
  • Keep responses short and direct.
  • Prefer the maintained skill surface over duplicated prompt logic.
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. yesterday First seen · 18 lines · 13 tokens per session scan A 67b0bf136a1e

Subscribe to this mod's changes

feature-dev is a command published in the GitHub repository noah-sheldon/ai-dev-kit (13 stars, last pushed 4mo ago), licensed MIT. It adds 13 tokens to every session and 85 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.