phosphorons

phosphorons is a skill for Claude Code from agentic-dev3o/devx-plugins. It costs 128 tokens per session (4,245 once invoked), scanned A, original, MIT.

A guided product-definition workflow that questions your product choices and ends with a functional specification in HTML. A functional specification explains what a product should do so a designer can mock it up and a developer can build it.

In plain words
What is it for?
Use it to research the existing product context, define its purpose and audience, decide on features, and produce implementation-ready requirements.
Why use it?
It exposes unclear assumptions and unresolved choices before design or coding starts.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: names the AskUserQuestion tool.

Part of the phosphorons plugin — 1 skill shipped together

Good fit Use it to research the existing product context, define its purpose and audience, decide on features, and produce implementation-ready requirements.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/agentic-dev3o/devx-plugins/phosphorons
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 agentic-dev3o/devx-plugins --skill phosphorons
Clone the repo
git clone --depth 1 https://github.com/agentic-dev3o/devx-plugins

Made for: Claude Code.

Or install phosphorons, the plugin that ships this one along with the rest of its 1 skill.

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 phosphorons

README.md
[![agentmods](https://agentmods.dev/badge/skills/agentic-dev3o/devx-plugins/phosphorons/github.svg)](https://agentmods.dev/skills/agentic-dev3o/devx-plugins/phosphorons)
Your own site
<a href="https://agentmods.dev/skills/agentic-dev3o/devx-plugins/phosphorons"><img src="https://agentmods.dev/badge/skills/agentic-dev3o/devx-plugins/phosphorons/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 phosphorons

Your own site · 80×15
<a href="https://agentmods.dev/skills/agentic-dev3o/devx-plugins/phosphorons"><img src="https://agentmods.dev/badge/skills/agentic-dev3o/devx-plugins/phosphorons.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,245 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 $0.00128 $0.04245
Opus 5.5 $0.00051 $0.01698
Sonnet 5.5 $0.00026 $0.00849
Haiku 4.5 $0.00013 $0.00424

Measured 10d ago against content hash 57e10274ed7a, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

phosphorons 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 10d 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/phosphorons/skills/phosphorons/SKILL.md · 185 lines

How it starts

The opening of the file, as written. The whole thing — 185 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Phosphorons : définir un produit qui tient la route

Ton rôle : mettre l'utilisateur sur le grill jusqu'à ce que la définition de son produit tienne la route, avant que quiconque ne dessine un écran ou n'écrive une ligne de code. Tu termines par une spécification fonctionnelle (la spec) qu'un designer peut maquetter et qu'un développeur, ou un agent de code, peut implémenter sans revenir avec des questions.

Deux responsabilités à ne jamais confondre :

  • Les faits, c'est ton affaire. Tout ce qui se trouve dans le dépôt, la documentation, les notes jointes ou sur le web, tu le cherches toi-même (via un sous-agent si tu en disposes). Ne demande jamais à l'utilisateur ce que tu peux lire, et n'avance aucun fait (concurrent, chiffre, réglementation) que tu n'as pas vérifié.
  • Les décisions reviennent à l'utilisateur. Tu lui soumets chaque arbitrage avec ta recommandation, puis tu attends sa réponse.

Avancement

Recopie cette checklist et tiens-la à jour dans tes réponses. Un niveau ne s'ouvre que lorsque le précédent tient :

Avancement :
- [ ] 0 Existant : documents lus, slug et langue fixés
- [ ] 1 Cadre : produit, destination, raison d'être
- [ ] 2 Pour qui : personas (situation, enjeu, rôle dans la décision)
- [ ] 3 Pari : pari, ce qui l'invaliderait, état cible (+ pourquoi maintenant)
- [ ] 4 Principes : garde-fous testables, rattachés au pari
- [ ] 5 Fonctionnalités : carte de la v1 validée
- [ ] 6 Détail : objets métier, parcours, écrans, règles, critères d'acceptation
- [ ] 7 Cohérence : contradictions et questions ouvertes listées
- [ ] Spec vérifiée, validée et livrée

Le déroulé d'un tour

Si le tool AskUserQuestion est disponible, pose chaque tour avec lui plutôt que dans le chat : un tour par appel, une question par entrée, ta recommandation en première option, marquée « (Recommandé) ».

À chaque tour, pose toutes les questions débloquées du niveau en cours, c'est-à-dire celles dont les prérequis sont déjà tranchés, dans la limite de quatre. Ne pose jamais une question d'un niveau qui n'est pas encore ouvert. Garde les plus structurantes et, pour les autres, avance une hypothèse explicite que l'utilisateur peut renverser. Une question qui dépend d'une réponse attendue dans ce même tour passe au tour suivant. Pour formuler tes questions et repérer les réponses à ne pas laisser passer, appuie-toi sur references/banque-de-questions.md, qui a une section par niveau.

Read the full file on GitHub · 185 lines

Files

What ships with it

3 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. 10d ago First seen · 185 lines · 128 tokens per session scan A 57e10274ed7a

Subscribe to this mod's changes

phosphorons is a skill published in the GitHub repository agentic-dev3o/devx-plugins (12 stars, last pushed 10d ago), licensed MIT. It adds 128 tokens to every session and 4,245 once invoked, about $0.0005 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 2026-10-09.

Related

Other skills, from other repositories

webgl-holographic-foil

A self-contained WebGL2 hero: thin-film interference over a crushed-foil surface whose palette shifts with the viewing angle; move the cursor to tilt the film.

nexu-io/open-design · 41 tokens

html-ppt-hermes-cyber-terminal

OpenDesign + BYOK: choosing and wiring your own model, hands-on — cost, quality, and the routing decision. Built as a decision-grade AI literacy deck for engineers, IT, applied-AI teams.

nexu-io/open-design · 53 tokens

html-ppt-taste-brutalist

16:9 HTML deck in tactical-telemetry / CRT-terminal taste. Deactivated-CRT charcoal slides, white-phosphor monospace, hazard-red accent, scanline overlay, ASCII syntax, density over decoration. Distilled from Leonxlnx/taste-skill brutalist-skill (Tactical Telemetry mode).

nexu-io/open-design · 78 tokens

visual-ralph

Visual Ralph orchestration for frontend UI from generated references, static references, or live URL targets, using $ultragoal with built-in visual verdict and pixel-diff evidence until the implementation matches and leaves a reproducible design system.

Yeachan-Heo/oh-my-codex · 52 tokens

glance-canonical-layouts

Use this skill to create home screen widgets using Jetpack Glance Canonical Layouts from the Android Platform Samples project, or when asked to implement standard widget layout patterns (including Check List, Image Grid, Snap Scrolling, and Standard Toolbar).

android/skills · 56 tokens

accessibility

Consolidated accessibility skill entrypoint for WCAG 2.2, ARIA Authoring Practices, cognitive accessibility, Section 508, EN 301 549, design intent verification, and the Accessibility Planner workflow.

microsoft/hve-core · 47 tokens