cross-platform

Guidelines for writing software that behaves consistently on macOS, Windows, Linux, and WSL, the Windows environment that runs Linux tools.

In plain words
What is it for?
Use it when adding platform support, detecting the current operating system, testing across systems, or implementing platform-specific notifications.
Why use it?
It avoids assuming that every computer has the same operating system, commands, notification tools, or system APIs.

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/mylee04/code-notify/cross-platform
Any agent
npx skills add mylee04/code-notify --skill cross-platform
Clone the repo
git clone --depth 1 https://github.com/mylee04/code-notify

Made for: Claude Code, Codex.

Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,383 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 $0.00015 $0.01383
Opus 5 $0.00008 $0.00691
Sonnet 5 $0.00003 $0.00277
Haiku 4.5 $0.00002 $0.00138

Measured 2d ago against content hash 16fc0356f253, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cross-platform 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 2d 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.

.claude/skills/cross-platform/SKILL.md · 247 lines

How it starts

The opening of the file, as written. The whole thing — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cross-Platform Development

When to Use

  • Adding new platform support
  • Writing platform-specific code
  • Testing across platforms

Platform Detection

Bash (macOS/Linux)

detect_os() {
    case "$(uname -s)" in
        Darwin*)    echo "macos" ;;
        Linux*)
            # Check for WSL
            if grep -qi microsoft /proc/version 2>/dev/null; then
                echo "wsl"
            else
                echo "linux"
            fi
            ;;
        CYGWIN*|MINGW*|MSYS*) echo "windows" ;;
        *)          echo "unknown" ;;
    esac
}

PowerShell (Windows)

function Get-Platform {
    if ($IsWindows -or $env:OS -eq "Windows_NT") {
        return "windows"
    } elseif ($IsLinux) {
        return "linux"
    } elseif ($IsMacOS) {
        return "macos"
    }
    return "unknown"
}

Notification Tools by Platform

Platform Primary Fallback
macOS terminal-notifier osascript
Linux notify-send zenity, wall
Windows BurntToast System.Windows.Forms
WSL wsl-notify-send notify-send

Platform-Specific Patterns

macOS

send_macos_notification() {
    local title="$1"
    local message="$2"

    if command -v terminal-notifier &> /dev/null; then
        terminal-notifier \
            -title "$title" \
            -message "$message" \
            -sound "Glass"
    else
        osascript -e "display notification \"$message\" with title \"$title\""
    fi
}

Linux

send_linux_notification() {
    local title="$1"
    local message="$2"

    if command -v notify-send &> /dev/null; then
        notify-send "$title" "$message" \
            --urgency=normal \
            --app-name="Code-Notify"
    elif command -v zenity &> /dev/null; then
        zenity --notification --text="$title\n$message"
    else
        echo "[$title] $message" | wall 2>/dev/null
    fi
}

Read the full file on GitHub · 247 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. 2d ago First seen · 247 lines · 15 tokens per session scan A 16fc0356f253

Subscribe to this mod's changes

cross-platform is a skill published in the GitHub repository mylee04/code-notify (288 stars, last pushed 4d ago), licensed MIT. It adds 15 tokens to every session and 1,383 once invoked, about $0.0001 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 2026-08-30.

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