xplat-checks

xplat-checks is a skill for Claude Code from dansasser/claude-code-marketplace. It costs 35 tokens per session (644 once invoked), scanned C, original, MIT.

A collection of checks for finding code that may work on one operating system but fail on another, especially Windows or Linux. It checks paths, line endings, environment variables, file-name casing, and shell commands.

In plain words
What is it for?
Use it to inspect Python projects for hardcoded path separators, incompatible environment variables, mixed line endings, case-sensitive imports, and shell commands that are not portable.
Why use it?
It catches platform-specific assumptions before users on another operating system encounter failures.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: reads .claude/ paths.

Part of the preflight plugin — 2 skills, 8 commands, 11 agents shipped together

Good fit Use it to inspect Python projects for hardcoded path separators, incompatible environment variables, mixed line endings, case-sensitive imports, and shell commands that are not portable.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/dansasser/claude-code-marketplace/xplat-checks
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 dansasser/claude-code-marketplace --skill xplat-checks
Clone the repo
git clone --depth 1 https://github.com/dansasser/claude-code-marketplace

Made for: Claude Code.

Or install preflight, the plugin that ships this one along with the rest of its 2 skills, 8 commands, 11 agents.

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 xplat-checks

README.md
[![agentmods](https://agentmods.dev/badge/skills/dansasser/claude-code-marketplace/xplat-checks/github.svg)](https://agentmods.dev/skills/dansasser/claude-code-marketplace/xplat-checks)
Your own site
<a href="https://agentmods.dev/skills/dansasser/claude-code-marketplace/xplat-checks"><img src="https://agentmods.dev/badge/skills/dansasser/claude-code-marketplace/xplat-checks/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 xplat-checks

Your own site · 80×15
<a href="https://agentmods.dev/skills/dansasser/claude-code-marketplace/xplat-checks"><img src="https://agentmods.dev/badge/skills/dansasser/claude-code-marketplace/xplat-checks.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 644 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 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 $0.00035 $0.00644
Opus 5 $0.00017 $0.00322
Sonnet 5 $0.00007 $0.00129
Haiku 4.5 $0.00003 $0.00064

Measured 9d ago against content hash 00010f1accda, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade C, and why

xplat-checks scanned grade C with 2 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.

The scan reads SKILL.md. This mod also ships 6 executable files (scripts/check_case_sensitivity.py, scripts/check_env_vars.py, scripts/check_line_endings.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

| Shell command | `os.system("rm -rf x")` | `shutil.rmtree("x")` |

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

- os.system() calls
plugins/preflight/skills/xplat-checks/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cross-Platform Checks Skill

Scripts for detecting cross-platform compatibility issues in Python code.

Scripts

check_paths.py

Detect hardcoded path separators.

python .claude/skills/xplat-checks/scripts/check_paths.py [directory]

Finds:

  • Hardcoded forward slashes in string paths
  • Hardcoded backslashes
  • Forward slashes inside os.path.join()

check_line_endings.py

Detect line ending issues.

python .claude/skills/xplat-checks/scripts/check_line_endings.py [directory]

Finds:

  • Files with CRLF line endings
  • Mixed line endings in single file
  • Missing .gitattributes

check_env_vars.py

Find platform-specific environment variable usage.

python .claude/skills/xplat-checks/scripts/check_env_vars.py [directory]

Finds:

  • $HOME, $USER (Unix-only)
  • %USERPROFILE%, %USERNAME%, %TEMP% (Windows-only)

check_case_sensitivity.py

Detect case sensitivity issues.

python .claude/skills/xplat-checks/scripts/check_case_sensitivity.py [directory]

Finds:

  • Files differing only by case
  • Import statements with wrong case

check_shell_commands.py

Detect shell command compatibility issues.

python .claude/skills/xplat-checks/scripts/check_shell_commands.py [directory]

Finds:

  • os.system() calls
  • subprocess with shell=True
  • Bash-specific commands

check_temp_paths.py

Find hardcoded temp directory paths.

python .claude/skills/xplat-checks/scripts/check_temp_paths.py [directory]

Finds:

  • /tmp references
  • C:\Temp references
  • /var/tmp references

Output Format

All scripts output JSON:

{
  "status": "PASS|FAIL",
  "files_scanned": 156,
  "issues": [
    {
      "file": "src/config.py",
      "line": 47,
      "column": 12,
      "issue": "Hardcoded forward slash in path",
      "code": "config_path = 'data/config.yaml'",
      "suggestion": "Use Path('data') / 'config.yaml'"
    }
  ]
}

Fix Reference

Issue Bad Good
Path separator "data/file.txt" Path("data") / "file.txt"
Home directory os.environ["HOME"] Path.home()
Temp directory "/tmp/file" Path(tempfile.gettempdir()) / "file"
Shell command os.system("rm -rf x") shutil.rmtree("x")
Username os.environ["USER"] getpass.getuser()

Read the full file on GitHub · 118 lines

Files

What ships with it

6 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. 9d ago First seen · 118 lines · 35 tokens per session scan C 00010f1accda

Subscribe to this mod's changes

xplat-checks is a skill published in the GitHub repository dansasser/claude-code-marketplace (9 stars, last pushed 4mo ago), licensed MIT. It adds 35 tokens to every session and 644 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it C with 2 findings (recursive force delete, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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