file-upload-testing

file-upload-testing is a skill for Claude Code, Codex from xAmirHamza77/PenKit51. It costs 19 tokens per session (3,569 once invoked), scanned A, original, no licence file.

A security-testing guide for web forms and APIs that accept uploaded files.

In plain words
What is it for?
Use it to check file-extension checks, content-type handling, and protection against path-traversal attacks.
Why use it?
It helps find ways an attacker could disguise a file, alter its reported type, or use its name to access another path.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

Good fit Use it to check file-extension checks, content-type handling, and protection against path-traversal attacks.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/xamirhamza77/penkit51/file-upload-testing
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 xAmirHamza77/PenKit51 --skill file-upload-testing
Clone the repo
git clone --depth 1 https://github.com/xAmirHamza77/PenKit51

Made for: Claude Code, 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.

agentmods badge for file-upload-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/xamirhamza77/penkit51/file-upload-testing.svg)](https://agentmods.dev/skills/xamirhamza77/penkit51/file-upload-testing)
Your own site
<a href="https://agentmods.dev/skills/xamirhamza77/penkit51/file-upload-testing"><img src="https://agentmods.dev/badge/skills/xamirhamza77/penkit51/file-upload-testing.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,569 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00019 $0.03569
Opus 5 $0.00010 $0.01784
Sonnet 5 $0.00004 $0.00714
Haiku 4.5 $0.00002 $0.00357

Measured 8d ago against content hash c320826683a8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

file-upload-testing scanned grade A 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 8d 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.

Sends data to an external URLlowData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

requests.post('http://target.com/upload', files=files)

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

requests.post('http://target.com/upload', files=files)
skills/file-upload-testing/SKILL.md · 529 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 8d ago First seen · 529 lines · 19 tokens per session scan A c320826683a8

Subscribe to this mod's changes

file-upload-testing is a skill published in the GitHub repository xAmirHamza77/PenKit51 (2 stars, last pushed 2mo ago), with no licence file. It adds 19 tokens to every session and 3,569 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 2 findings (sends data to an external url, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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