What is race-condition?

A guide to race-condition attacks, where timing lets two operations access or change the same resource at nearly the same time.

Testing concurrent HTTP requests, including HTTP/2 single-packet attacks.

It helps reveal bugs that normal, one-at-a-time tests miss, such as duplicate actions or inconsistent state.

race-condition — Skill for Claude Code by mohdhaji87

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 mohdhaji87/payloadsallthethings-skills --skill race-condition

Clone the repo

git clone --depth 1 https://github.com/mohdhaji87/payloadsallthethings-skills

Made for: Claude Code.

Or install payloadsallthethings, the plugin that ships this one along with the rest of its 61 skills.

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/mohdhaji87/payloadsallthethings-skills/race-condition/github.svg)](https://agentmods.dev/skills/mohdhaji87/payloadsallthethings-skills/race-condition)

Your own site

<a href="https://agentmods.dev/skills/mohdhaji87/payloadsallthethings-skills/race-condition"><img src="https://agentmods.dev/badge/skills/mohdhaji87/payloadsallthethings-skills/race-condition/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/mohdhaji87/payloadsallthethings-skills/race-condition"><img src="https://agentmods.dev/badge/skills/mohdhaji87/payloadsallthethings-skills/race-condition.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,735 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 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.

Model	Per session	Once invoked
Fable 5.1	$0.00020	$0.01735
Opus 5	$0.00010	$0.00868
Sonnet 5	$0.00004	$0.00347
Haiku 4.5	$0.00002	$0.00173

Measured 12d ago against content hash 415c6370999c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade B, and why

race-condition scanned grade B 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 12d 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 URLmediumData 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.

response = requests.post('https://target.com/api/withdraw',

Makes network callslowCapability

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

seq 1 100 | parallel -j 100 curl -s -X POST https://target.com/redeem -d "code=GIFTCODE"

payloadsallthethings/skills/race-condition/SKILL.md · 309 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.

12d ago First seen · 309 lines · 20 tokens per session scan B 415c6370999c

Subscribe to this mod's changes

race-condition is a skill published in the GitHub repository mohdhaji87/payloadsallthethings-skills (21 stars, last pushed 8mo ago), with no licence file. It adds 20 tokens to every session and 1,735 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B 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 2026-08-30.

Security Testing

research-engineer

An uncompromising Academic Research Engineer. Operates with absolute scientific rigor, objective criticism, and zero flair. Focuses on theoretical correctness, formal verification, and optimal implementation across any required technology.

davila7/claude-code-templates · 43 tokens

tika-eval-compare

Compare extracts from two Tika builds over a corpus to detect regressions in content, encoding, exceptions, and embedded-document handling. Use for "compare before/after extracts", "eval this change against the corpus".

apache/tika · 50 tokens

neuron-evaluation-engineer

Create and run AI evaluations with datasets, assertions, and output drivers in Neuron AI. Use this skill whenever the user mentions evaluation, testing AI systems, creating evaluators, dataset-driven testing, assertion-based validation, or wants to measure AI system performance. Also trigger for tasks involving…

neuron-core/neuron-ai · 77 tokens

race-condition