feature-spec-creator

An interview-based tool for writing a feature specification for an existing codebase. A feature specification is a written description of what should be built, how it should work, and what boundaries it has.

In plain words
What is it for?
Use it to plan a new feature, clarify its behavior and scope, inspect the relevant codebase, and produce a focused Markdown specification.
Why use it?
It surfaces unclear requirements, scope growth, and integration problems before implementation starts. The result gives another developer enough context to continue without repeating the interview.

Skill for Claude CodeCodex

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 skills/alteredcraft/claude-code-plugins/example-skill-code
Any agent
npx skills add AlteredCraft/claude-code-plugins --skill example-skill-code
Clone the repo
git clone --depth 1 https://github.com/AlteredCraft/claude-code-plugins

Made for: Claude Code, Codex.

Per session 107 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,676 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 1 finding. 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 $0.00107 $0.02676
Opus 5 $0.00053 $0.01338
Sonnet 5 $0.00021 $0.00535
Haiku 4.5 $0.00011 $0.00268

Measured yesterday against content hash 25645c7b4a11, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

feature-spec-creator scanned grade C with 1 finding 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.

Tells the agent never to refusehighAnti-refusal

Suppressing the ability to decline removes a core safety control; a later harmful request then succeeds.

- **Don't refuse to call out a contradiction because it might be awkward.** Surfacing them is the job. Frame as a question if uncertain ("am I looking at the right code?"), but don't paper over them.
plugins/anchored-interview/skills/create-skill/references/example-skill-code/SKILL.md · 146 lines

How it starts

The opening of the file, as written. The whole thing — 146 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Feature Spec Generator

Interview the user to produce a focused feature spec for an existing codebase. The output is a single markdown file the user can hand to a developer (or future-Claude) and have enough context to plan the work without re-asking the same questions.

Why this skill exists

A good spec is the cheapest place to surface scope creep, integration headaches, and contradictions between what the user describes and what the code actually does. Catching those at spec time costs minutes; catching them mid-implementation costs hours. The interview is the value — the markdown is just the artifact. The skill's job is to make that surfacing happen before code gets written.

Workflow

The sequence matters. Do not jump ahead.

1. Confirm the feature in one sentence

Before reading any code, ask the user what feature they want to spec, in one sentence. If they already said it clearly in the prompt, just paraphrase it back and ask "is that right?" — don't make them repeat themselves.

If their description is vague (e.g., "I want to improve the dashboard"), ask a single clarifying question to get to a concrete feature before scanning code. Scanning the wrong area is wasted work.

2. Lightweight code scan to seed context

The code scan is steered by the seed, not exhaustive. Read what the seed makes relevant; ignore what it doesn't. The goal is to know enough to ask sharp anchored questions in step 3 and recognize when an answer contradicts the code — not to understand the whole codebase. Deeper reading for implementation happens after the spec narrows the focus, not here.

Aim for a quick scan, not a full architectural review. Specifically:

  • Locate the area of the codebase the feature touches (Glob/Grep for likely module names, route handlers, models, components).
  • Read 2–4 of the most relevant files end-to-end.
  • Skim adjacent files (tests, configs, types) to spot patterns and constraints.
  • Note: existing similar features, the data model around the affected area, integration points (APIs, queues, DB tables), and any obvious tech-debt or workarounds in the area.

Read the full file on GitHub · 146 lines

Files

What ships with it

1 file 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. yesterday First seen · 146 lines · 107 tokens per session scan C 25645c7b4a11

Subscribe to this mod's changes

feature-spec-creator is a skill published in the GitHub repository AlteredCraft/claude-code-plugins (13 stars, last pushed 3mo ago), licensed MIT. It adds 107 tokens to every session and 2,676 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it C with 1 finding (tells the agent never to refuse). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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