skill-dev

A development tool for creating or changing Prismstack’s own product skills, following the project’s written guidelines.

In plain words
What is it for?
Use it to add features, fix problems, or restructure one of the product skills. It is not for editing a user’s domain-specific skills.
Why use it?
It prevents skill changes from being made by guesswork or without checking the relevant quality rules.

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/fagemx/prismstack/skill-dev
Any agent
npx skills add fagemx/prismstack --skill skill-dev
Clone the repo
git clone --depth 1 https://github.com/fagemx/prismstack

Made for: Claude Code, Codex.

Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 965 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 $0.00064 $0.00965
Opus 5 $0.00032 $0.00483
Sonnet 5 $0.00013 $0.00193
Haiku 4.5 $0.00006 $0.00097

Measured yesterday against content hash 0d4708805a18, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

skill-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.

.claude/skills/skill-dev/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/skill-dev: Develop Prismstack Product Skills

You are a Prismstack skill developer. You modify the 10 product skills with discipline, ensuring every change follows the methodology.

Phase 0: Scope the Change

Parse $ARGUMENTS for the target skill and change description.

If not provided, ask:

  1. Which skill? (one of the 10 product skills in skills/*/SKILL.md)
  2. What change? (add feature, fix issue, refactor section, etc.)

Read the current SKILL.md for the target skill fully before making any change.

Phase 1: Load Relevant Methodology

Based on the type of change, read the appropriate methodology file:

Change Type Read This
Structure / sections skills/shared/methodology/skill-craft-guide.md
Scoring / rubric skills/shared/methodology/quality-standards.md
Artifact flow / wiring skills/shared/methodology/system-wiring-guide.md
Fix loop / triage skills/shared/methodology/fix-loop-guide.md
Context / accumulation skills/shared/methodology/context-accumulation-guide.md

If the change spans multiple areas, read all relevant files. Do not guess at methodology — read it.

Phase 2: Make the Change

Rules for editing:

  • Minimal and surgical. Change only what is needed. Do not rewrite surrounding sections.
  • Read before edit. Always use Read tool on the file before using Edit tool. Never edit blind.
  • Preserve voice. Match the existing tone and formatting of the skill.
  • No scope creep. If you notice other issues while editing, note them but do not fix them now. One change per /skill-dev invocation.

Use the Edit tool (not Write) for modifications. Write is only for new files.

Phase 3: Self-Check (Quick 15D)

After the edit, run a quick quality check on the modified skill:

  1. Read skills/shared/methodology/quality-standards.md for the 15D rubric
  2. Score the modified skill on all 15 dimensions (1-5 scale)
  3. Compare to a rough pre-edit baseline (your reading from Phase 0)

Read the full file on GitHub · 97 lines

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 · 97 lines · 64 tokens per session scan A 0d4708805a18

Subscribe to this mod's changes

skill-dev is a skill published in the GitHub repository fagemx/prismstack (2 stars, last pushed 4mo ago), licensed MIT. It adds 64 tokens to every session and 965 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.

Related

Other skills, from other repositories

ebay-sold-listings-search

All process output to user (progress updates, process notifications) follows the user's language.

browser-act/skills · 221 tokens

youtube-channel-business-email

YouTube channel business email and contact extractor: accepts a channel id (UCxxx), handle (@name), or URL; navigates the channel About view; extracts the business email from the description text plus full channel metadata (name, id, country, subscriber count, view count, video count, joined date, external links…

browser-act/skills · 324 tokens

webcrawler-deep-crawl

Deep-crawl any website from start URLs, return per-page LLM-ready text/markdown/HTML plus metadata (title, description, author, language, canonical URL, OG) and in-scope outbound links. Use when user mentions deep crawl website, recursive crawl, crawl a whole site, scrape entire website, scrape docs site, scrape…

browser-act/skills · 215 tokens

1688-product-detail

Extracts comprehensive wholesale product data from 1688.com product detail pages: title, tiered pricing, SKU variants with dimensions/weight, product images, seller info, shop scores, buyer protection, cross-border flags, product attributes, coupon/promotion data, and review stats. Use when user mentions 1688…

browser-act/skills · 212 tokens

amazon-listing-competitor-analysis-skill

This skill helps users analyze Amazon competitor listings by ASIN and produce structured competitive intelligence plus strategic opportunity points for their own go-to-market. The Agent should proactively apply this skill when users want to analyze a competitor Amazon listing by ASIN, understand what a top-ranked…

browser-act/skills · 172 tokens

amazon-product-detail

Amazon product detail page scraper: extract full product data from any open Amazon product detail URL (any /dp/{asin} or /gp/product/{asin} page across all Amazon regional TLDs) — returns asin, url, title, brand, price, listPrice, stars, reviewsCount, starsBreakdown (5/4/3/2/1 star percentages), answeredQuestions…

browser-act/skills · 472 tokens