What is platform-detector?

A project-analysis helper that identifies where software runs, how it is distributed, and which platform rules and quality requirements apply.

Use it to build a platform matrix for web, mobile, desktop, server, game, or other products, including their runtime, distribution channel, and relevant checks.

It prevents testing, security, accessibility, performance, and release decisions from being made without knowing the target platform.

platform-detector — Skill for Codex by ashermahonin/agentic-skills

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 ashermahonin/agentic-skills --skill platform-detector

Clone the repo

git clone --depth 1 https://github.com/ashermahonin/agentic-skills

Made for: 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/ashermahonin/agentic-skills/platform-detector/github.svg)](https://agentmods.dev/skills/ashermahonin/agentic-skills/platform-detector)

Your own site

<a href="https://agentmods.dev/skills/ashermahonin/agentic-skills/platform-detector"><img src="https://agentmods.dev/badge/skills/ashermahonin/agentic-skills/platform-detector/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/ashermahonin/agentic-skills/platform-detector"><img src="https://agentmods.dev/badge/skills/ashermahonin/agentic-skills/platform-detector.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 70 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 746 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.

Model	Per session	Once invoked
Fable 5.1	$0.00070	$0.00746
Opus 5.5	$0.00028	$0.00298
Sonnet 5.5	$0.00014	$0.00149
Haiku 4.5	$0.00007	$0.00075

Measured 2mo ago against content hash 209630025ce9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

platform-detector 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 2mo 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.

agentic/skills/platform-detector/SKILL.md · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Platform Detector

Purpose

Translate a fuzzy product idea or an unfamiliar repository into a concrete target-platform matrix the rest of the skill chain can plan against. Without this, security, testing, performance, accessibility, and store-policy choices drift.

Inputs

Read references/platform-matrix.md.
Collect inputs from init-project: stack fingerprint, user intent, deployment markers.
List the explicit platforms named by the user. If none were named, derive candidates from fingerprint markers and ask the user to confirm before locking in.
For each candidate platform, name the store/distribution policy that applies (App Store, Google Play, Microsoft Store, Steam, web, internal enterprise, console SDK, package registry).

Decision process

Build the platform matrix: rows are platforms; columns are runtime, distribution channel, accessibility baseline, performance budget, security track, testing matrix, telemetry constraints.
Mark which cells are unknown and would benefit from Context7 MCP lookups (current SDK version, store policy revision, browser support floor, OS version coverage).
For each platform, pin the security track: web/API/backend → security-owasp-web; native iOS/Android → security-mobile-masvs plus backend/API security-owasp-web when applicable; LLM feature → security-owasp-llm; agentic surface → security-owasp-agentic; game → cheat-surface review plus dependency CVE checks.
Set a minimum testing matrix: e.g., web → 2 browser engines + 1 mobile viewport; iOS → 2 device sizes + dark mode + accessibility audit; Android → 2 API levels + at least one form factor.
Surface conflicts: platforms whose budgets, policies, or stores disagree (for example, an iOS feature blocked by App Store rules but used freely on web).
Hand the matrix to architecture-review and requirements-quality so non-functional requirements pick it up automatically.

Decision boundaries

Use Context7 MCP whenever current store policy, browser support, OS version table, or platform SDK behavior changes the answer.
Keep a decision trace: candidate platforms, why included or excluded, store-policy risks, accessibility floor, security track per platform.
Escalate before locking in a platform whose store policy or certification path could block release.

Read the full file on GitHub · 56 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.

2mo ago First seen · 56 lines · 70 tokens per session scan A 209630025ce9

Subscribe to this mod's changes

platform-detector is a skill published in the GitHub repository ashermahonin/agentic-skills (10 stars, last pushed 2mo ago), licensed MIT. It adds 70 tokens to every session and 746 once invoked, about $0.0003 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 2026-08-31.

Planning

platform-detector next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
platform-detectorashermahonin/agentic-skills	Skill	10	2mo ago	MIT	A	70	Codex
imagegenopenai/codex	Skill	133k	yesterday	Apache-2.0	A	113	Codex
playwright-climicrosoft/playwright	Skill	99k	yesterday	Apache-2.0	A	19	Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	4d ago	MIT	A	200	Claude Code, Codex
systematic-debuggingobra/superpowers	Skill	313k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	95	Claude Code
next-partial-prefetching-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	103	Claude Code