feature-implementation

feature-implementation is a skill for Claude Code, Codex from protect-my-hair/nucleus-marketplace. It costs 21 tokens per session (995 once invoked), scanned A, original, MIT.

A controlled process for implementing one feature after its design review and implementation plan are confirmed. It checks specifications, UI design requirements, planned files, acceptance criteria, evidence, and verification commands before edits.

In plain words
What is it for?
Use it to implement feature code, tests, or styles while following the approved plan and recording the evidence needed to verify the result.
Why use it?
It keeps coding within the approved feature scope and stops work when required specifications, design sources, approvals, or edit checks are missing.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the nucleus plugin — 27 skills, 1 agent, 1 hook shipped together

Good fit Use it to implement feature code, tests, or styles while following the approved plan and recording the evidence needed to verify the result.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/protect-my-hair/nucleus-marketplace/feature-implementation
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 protect-my-hair/nucleus-marketplace --skill feature-implementation
Clone the repo
git clone --depth 1 https://github.com/protect-my-hair/nucleus-marketplace

Made for: Claude Code, Codex.

Or install nucleus, the plugin that ships this one along with the rest of its 27 skills, 1 agent, 1 hook.

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-implementation

README.md
[![agentmods](https://agentmods.dev/badge/skills/protect-my-hair/nucleus-marketplace/feature-implementation/github.svg)](https://agentmods.dev/skills/protect-my-hair/nucleus-marketplace/feature-implementation)
Your own site
<a href="https://agentmods.dev/skills/protect-my-hair/nucleus-marketplace/feature-implementation"><img src="https://agentmods.dev/badge/skills/protect-my-hair/nucleus-marketplace/feature-implementation/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 feature-implementation

Your own site · 80×15
<a href="https://agentmods.dev/skills/protect-my-hair/nucleus-marketplace/feature-implementation"><img src="https://agentmods.dev/badge/skills/protect-my-hair/nucleus-marketplace/feature-implementation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 995 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 $0.00021 $0.00995
Opus 5.5 $0.00008 $0.00398
Sonnet 5.5 $0.00004 $0.00199
Haiku 4.5 $0.00002 $0.00100

Measured 1mo ago against content hash 32ab90f4d781, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

feature-implementation 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 1mo 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.

plugins/nucleus/skills/feature-implementation/SKILL.md · 48 lines

How it starts

The opening of the file, as written. The whole thing — 48 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Feature Implementation

核心原则

只实现当前特性实施计划覆盖的内容。

实施计划声明 uiDesign.applicability=required 时,未读取 UI 设计源、Pencil frame / UI 状态映射、公共组件 / 公共样式契约和视觉证据要求前,不得写 UI 相关源码或样式。

实施计划声明 uiDesign.applicability=candidate-found 时,未取得候选设计源是否相关的人工计划确认前,不得写 UI 相关源码或样式;确认相关后必须回到实施计划补齐 required 级 frame 映射和视觉证据。

实施计划缺少 developmentSpecs,或 developmentSpecs.status=missing 但没有人工计划明确接受 setup gap / 先补齐 docs/specs/** 的结论时,不得写源码、测试或样式。

实施计划缺少 specAnchor,或没有从磁盘重读 .nucleus/runs/<workflowRunId>/spec-anchor.json 及其 sourceEvidencePaths,或 specAnchor.status 不是 ready 且没有人工计划明确接受 gap 时,不得写源码、测试或样式。

行为纪律

  • 先读取当前 featurePath、特性设计评审事实、实施计划确认事实、实施计划和测试计划;人工事实必须来自对话、PMS 状态或明确审批上下文,不能来自 summary.md、result.json、candidate 或 multi-review report。
  • 每次进入实现、上下文压缩后恢复、切换 task、写源码前、写样式前、写 UI 前,都必须重读实施计划的 specAnchor、.nucleus/runs/<workflowRunId>/spec-anchor.json 和其中 sourceEvidencePaths;不得把对话摘要当成 specs 或 UI 设计事实。
  • 写任何源码、测试或样式前,先执行 pre-edit gate:确认当前 task 的 planned files、适用 rule id、acceptance、evidence 和 verify command;缺任一项时回到实施计划评审。
  • 读取实施计划的 developmentSpecs 和 .nucleus/runs/<workflowRunId>/development-specs-evidence.json;存在 docs/specs/rules/** 时,先读适用规则再改代码;缺失时,先补齐规范或取得人工计划豁免。
  • 只修改实施计划声明的代码区域、测试区域和文档区域。
  • 代码、测试和文档改动必须能回指当前 featurePath。
  • 写 UI 前必须读取实施计划的 uiDesign、.nucleus/runs/<workflowRunId>/ui-design-evidence.json、对应 Pencil frame / 用户设计稿、相邻页面、公共组件、公共 CSS / token 或页面级样式;candidate-found 必须先取得人工相关性结论;没有设计源时,也必须按现有公共组件和既有样式实现。
  • UI 实现后必须产出计划声明的截图、Pencil frame 对照、人工视觉证据或等价报告;缺证据时不得声称完成。
  • 开发完成前必须执行 completion gate:按 changed files 重新计算 applicable rules -> evidence coverage;缺 blocking rule 证据、UI frame 未覆盖或 factsManifestHash stale 时不得触发完成评审。
  • 发现计划不成立、依赖缺失或 scope 变化时停住,回到计划或设计评审节点。
  • 开发完成后必须触发 multi-review,覆盖 code-review、方案一致性和计划满足度。

禁止

  • 顺手做无关重构。
  • 合并多个特性的实现。
  • 在计划外写接口、数据结构、权限或外部依赖。
  • 忽略 docs/specs/** 规范事实源,或把规范缺失当作无约束。
  • 依赖压缩后的对话摘要继续实现,而不重读 specAnchor.sourceEvidencePaths。
  • 使用未确认存在的 CSS 类、跳过公共页面布局 / 组件模式,或在有 Pencil 设计源时只按个人判断重画界面。
  • 用测试通过替代设计一致性和计划满足度评审。
  • 创建、批准、合入或发布 MR/PR。

Read the full file on GitHub · 48 lines

Files

What ships with it

2 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. 1mo ago First seen · 48 lines · 21 tokens per session scan A 32ab90f4d781

Subscribe to this mod's changes

feature-implementation is a skill published in the GitHub repository protect-my-hair/nucleus-marketplace (164 stars, last pushed 3mo ago), licensed MIT. It adds 21 tokens to every session and 995 once invoked, about $0.0001 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 2026-08-30.

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