injection-checking

injection-checking is a skill for Claude Code, Codex from JustineDevs/premortem. It costs 50 tokens per session (597 once invoked), scanned A, a copy of injection-checking, Apache-2.0.

A routing guide for testing cases where user-controlled input reaches an interpreter, such as a browser, database, template engine, XML parser, URL fetcher, or shell command.

In plain words
What is it for?
It is for choosing workflows for cross-site scripting, SQL injection, server-side request forgery, template injection, command injection, XML injection, and related issues.
Why use it?
It helps determine which kind of injection test fits the data flow instead of applying unrelated checks.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

Good fit It is for choosing workflows for cross-site scripting, SQL injection, server-side request forgery, template injection, command injection, XML injection, and related issues.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/justinedevs/premortem/injection-checking
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 JustineDevs/premortem --skill injection-checking
Clone the repo
git clone --depth 1 https://github.com/JustineDevs/premortem

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 injection-checking

README.md
[![agentmods](https://agentmods.dev/badge/skills/justinedevs/premortem/injection-checking/github.svg)](https://agentmods.dev/skills/justinedevs/premortem/injection-checking)
Your own site
<a href="https://agentmods.dev/skills/justinedevs/premortem/injection-checking"><img src="https://agentmods.dev/badge/skills/justinedevs/premortem/injection-checking/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 injection-checking

Your own site · 80×15
<a href="https://agentmods.dev/skills/justinedevs/premortem/injection-checking"><img src="https://agentmods.dev/badge/skills/justinedevs/premortem/injection-checking.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 50 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 597 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 100% copy Near-identical to another mod 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 $0.00050 $0.00597
Opus 5 $0.00025 $0.00298
Sonnet 5 $0.00010 $0.00119
Haiku 4.5 $0.00005 $0.00060

Measured 9d ago against content hash 5a6d03027213, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

injection-checking 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 9d 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.

Origin

This is a copy

100% identical to injection-checking — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/injection-checking/SKILL.md · 50 lines

What it actually says

Injection Testing Router

This is the routing entry point when input reaches a dangerous interpreter or execution environment.

After confirming this is an injection-class issue, use it to decide whether it is mainly browser context, database, template engine, server-side requests, XML parsing, or system commands.

When to Use

  • Input reaches HTML, JS, SQL, templates, URL fetchers, XML parsers, or shell
  • You have not yet decided whether to start with XSS, SQLi, SSRF, XXE, SSTI, CMDi, or NoSQL
  • You need to choose the correct deep-topic skill based on input flow

Skill Map

  1. First identify the final sink of the input
  2. Then choose the topic skill that best matches that interpreter
  3. Small payload samples and quick triage are merged into each main skill; no extra payload router is needed
Files

What ships with it

1 file 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 · 50 lines · 50 tokens per session scan A 5a6d03027213

Subscribe to this mod's changes

injection-checking is a skill published in the GitHub repository JustineDevs/premortem (2 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 50 tokens to every session and 597 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to injection-checking, differing in 0 lines, and is treated as a copy.

Related

Other skills, from other repositories

extract-api

This skill should be used when the user asks to "extract API from", "import API from", "add commands from this repo", "register API from docs", "convert docs to CLI commands", "import Postman collection", or provides a GitHub repository URL, a documentation site URL, a Postman collection file/URL, or a local API…

hesedcasa/sdkck · 86 tokens

aws-cli

CLI-first AWS orchestration skill for Lambda, ECS/Fargate, and S3 workflows rooted in .☁️ runbooks.

elasticdotventures/_b00t_ · 31 tokens

azure-eventhub-dotnet

Azure Event Hubs SDK for .NET. Use for high-throughput event streaming: sending events (EventHubProducerClient, EventHubBufferedProducerClient), receiving events (EventProcessorClient with checkpointing), partition management, and real-time data ingestion. Triggers: "Event Hubs", "event streaming"…

microsoft/skills · 94 tokens

voiden

Create and edit Voiden .void files for API testing. Covers the .void file format and all enabled extension block types.

VoidenHQ/voiden · 28 tokens

notion

Notion workspace integration for searching pages, managing databases, creating postmortems, and exporting RCA findings.

Arvo-AI/aurora · 23 tokens

ak-add-integration

Add a messaging platform integration to an existing Agent Kernel project. This skill guides you through adding Slack, WhatsApp, Messenger, Instagram, Telegram, Teams, or Gmail integration by generating configuration, updating dependencies, and setting up webhook handlers. Designed for users extending their agents.

yaalalabs/agent-kernel · 59 tokens