write-decision-complete-feature-spec

write-decision-complete-feature-spec is a skill for Claude Code, Codex from andrewsrigom/agent-skills. It costs 60 tokens per session (655 once invoked), scanned A, original, MIT.

A guide for writing and reviewing feature specifications before coding starts. It focuses on the goal, user behavior, boundaries, edge cases, acceptance checks, and decisions needed to implement the feature.

In plain words
What is it for?
Use it when a feature request needs an implementation-ready specification. It helps define scope and non-goals, success criteria, risky ambiguities, and concrete verification steps.
Why use it?
It reduces guesswork during implementation by resolving important questions about data, permissions, failures, loading states, migrations, and ownership in advance.

Skill for Claude CodeCodex

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

Good fit Use it when a feature request needs an implementation-ready specification. It helps define scope and non-goals, success criteria, risky ambiguities, and concrete verification steps.

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Install with agentmods
npx agentmods add skills/andrewsrigom/agent-skills/write-decision-complete-feature-spec
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 andrewsrigom/agent-skills --skill write-decision-complete-feature-spec
Clone the repo
git clone --depth 1 https://github.com/andrewsrigom/agent-skills

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 write-decision-complete-feature-spec

README.md
[![agentmods](https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/write-decision-complete-feature-spec/github.svg)](https://agentmods.dev/skills/andrewsrigom/agent-skills/write-decision-complete-feature-spec)
Your own site
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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 write-decision-complete-feature-spec

Your own site · 80×15
<a href="https://agentmods.dev/skills/andrewsrigom/agent-skills/write-decision-complete-feature-spec"><img src="https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/write-decision-complete-feature-spec.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 655 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 $0.00060 $0.00655
Opus 5 $0.00030 $0.00328
Sonnet 5 $0.00012 $0.00131
Haiku 4.5 $0.00006 $0.00065

Measured 9d ago against content hash baf3cda107f5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

write-decision-complete-feature-spec 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 9d 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.

engineering/write-decision-complete-feature-spec/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Write Decision Complete Feature Spec

Use this skill when the team needs a spec that closes decisions before implementation, not a polished document full of unresolved choices.

Scope

  • feature specs before implementation
  • reducing ambiguity before coding starts
  • locking scope, success criteria, and boundaries
  • identifying missing decisions that would otherwise be invented during implementation
  • turning vague requests into implementation-ready specs

Default path

  1. State the feature goal in plain language.
  2. Name the success criteria and who will judge them.
  3. Define the user-facing behavior and the main flow first.
  4. Lock scope, non-goals, and ownership boundaries.
  5. Identify high-risk ambiguities:
    • data shape
    • permissions
    • failure behavior
    • loading and empty states
    • rollout or migration impact
  6. Resolve those ambiguities in the spec instead of leaving them to implementation.
  7. End with concrete acceptance criteria and verification steps.

When to deviate

  • Keep the spec lightweight when the feature is tiny and the boundary is already obvious.
  • Split the work into multiple specs if one document is trying to cover unrelated surfaces.
  • Route to request-refactor-plan instead when the work is primarily structural rather than behavioral.
  • Route to tdd once the contract is already stable and the next problem is implementation sequencing.

Guardrails

  • Do not call a spec complete if the implementer still has to choose core behavior.
  • Prefer decisions over option lists once enough context exists.
  • Keep the spec behavior-first; do not start with file layout or implementation trivia.
  • Separate in-scope decisions from future ideas and nice-to-haves.
  • Make non-goals explicit so the spec cannot silently expand during delivery.

Avoid

  • specs that mostly restate the prompt without making decisions
  • “TBD” in core behavior, permissions, or error handling
  • mixing rollout notes, architecture notes, and product behavior into one vague blob
  • turning the spec into a task list before the contract is actually stable
  • using broad phrases like “handle edge cases” without naming the actual cases

Read the full file on GitHub · 84 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. 9d ago First seen · 84 lines · 60 tokens per session scan A baf3cda107f5

Subscribe to this mod's changes

write-decision-complete-feature-spec is a skill published in the GitHub repository andrewsrigom/agent-skills (2 stars, last pushed 5mo ago), licensed MIT. It adds 60 tokens to every session and 655 once invoked, about $0.0003 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 2026-08-31.

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