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Sec Check

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waynesutton
sec-check

Security review checklist for Convex functions, auth logic, public queries, admin routes, webhooks, uploads, and AI-generated code. Use when reviewing code that touches user data, PII, or access control.

Overview

Publisherwaynesutton
Repositorymarkdown-site
Skill namesec-check
Stars
627
Forks
91
Bundled files
Instructions only
LicenseMIT
Links
  • Markdown instructions

    A SKILL.md file the model loads on demand, so it only costs tokens when a request actually matches.

  • Works with any LLM

    AI skills are plain Markdown, not provider-specific code, so this works with GPT, Claude, Gemini, Grok, or a local model.

  • Self-contained

    Everything the model needs lives in the instructions — no extra files to sync.

  • Open source

    Published by waynesutton on GitHub. Read the source before you install it.

Installation

Install the Sec Check AI skill in TypingMind to use it with any LLM, or drop it into another agent that reads SKILL.md.

1

Install in TypingMind

TypingMind installs a skill straight from its GitHub folder — it reads SKILL.md, bundles the resource files, and stores the result locally.

  1. Open the app and go to Plugins → Skills.
  2. Choose "Install from GitHub".
  3. Paste the skill folder URL below and confirm.
    https://github.com/waynesutton/markdown-site/tree/main/.claude/sec-check
  4. Enable the skill in any chat where you want it available.
Plugins → Skills → Add skill → From GitHub URL, then paste the folder URL and press Continue.
2

Install in another agent

Any agent that reads the Agent Skills format can use this skill — copy the folder into that agent's skills directory.

Claude Code — .claude/skills
git clone --depth 1 https://github.com/waynesutton/markdown-site.git /tmp/markdown-site
mkdir -p .claude/skills
cp -r /tmp/markdown-site/.claude/sec-check .claude/skills/sec-check
Restart Claude Code after copying so it picks up the new skill.

Use it in TypingMind

Enable Sec Check in any TypingMind chat and the model takes it from there. Its name and description sit in the system prompt, and the moment a request matches, the model loads the full instructions itself — you never invoke it by hand, and it costs no tokens until it is actually used.

The model loads Sec Check on its own as soon as a request matches it.

Works with any AI model

AI skills are plain Markdown instructions rather than provider-specific code, so Sec Check is not tied to the model it was written for. Install it once in TypingMind and use it with GPT-5, Claude, Gemini, Grok, DeepSeek, Mistral, Llama, or a local model you run yourself — all on your own API keys.

  • Loaded only when it is needed

    The system prompt carries just the name and description. The instructions are fetched on the first matching request, so an idle skill costs nothing.

  • Switch models mid-chat

    Because the skill is instructions rather than code, changing model does not break it — the next model reads the same SKILL.md.

Skill instructions

This is the SKILL.md content the model loads. Read it before installing — a skill is instructions your model will follow.

Security Review Skill

Use this skill when reviewing Convex functions, auth logic, public query shapes, admin routes, webhooks, uploads, or any AI generated code that touches user data.

When to use it

Reach for this skill when:

  • a mutation writes user or admin data
  • a public query returns package or user data
  • an internal function should be separated from a public wrapper
  • a form collects names, emails, or other contact info
  • a webhook, upload, or API key flow is added
  • AI generated code needs a security pass before shipping

Auth and ownership checks

  • Call ctx.auth.getUserIdentity() before authenticated writes.
  • Never trust client supplied user ids for ownership.
  • Prefer indexed ownership checks over fetch then compare patterns.
  • Use internalQuery, internalMutation, and internalAction for sensitive backend work.
  • Keep public wrappers thin. Do auth and access checks there, then call internal functions.
  • Return generic Not found style errors when you should not reveal existence.

Data exposure rules

  • Public queries should return public safe shapes only.
  • Strip PII like email, name, Discord handle, internal notes, AI review details, or admin metadata unless the caller is allowed to see them.
  • Add explicit return validators on public functions so the response shape stays tight.
  • Mutations should return minimal data, usually ids or null, not the submitted object.
  • Treat everything returned by a query as visible in browser DevTools and WebSocket traffic.

Sensitive integrations

  • Keep secrets in server side environment variables only.
  • Validate webhook signatures before processing.
  • Restrict CORS for sensitive endpoints.
  • Validate upload types and file sizes server side.
  • Do not send user PII into AI prompts when it is not required for the task.
  • Use simple actor labels like AI or System, not fake email addresses, for automated actions.

AI generated code checks

  • Watch for missing returns validators.
  • Watch for public query or mutation usage where internal* should be used.
  • Watch for ctx.db.get() plus client supplied ids in ownership checks.
  • Watch for full objects returned from public queries or mutations.
  • Watch for vague or over detailed error messages that leak internal state.

Verification checklist

  • Open the browser network panel and inspect WebSocket or XHR responses for sensitive fields.
  • Hard refresh after deploying security changes so cached subscriptions do not fool the test.
  • Verify public queries exclude PII and internal metadata.
  • Verify admin queries require auth and admin checks before returning full data.
  • Verify mutations return minimal data.
  • Verify any new action or integration logs full errors only on the server side.

Frequently asked questions

What does the Sec Check AI skill do?

Security review checklist for Convex functions, auth logic, public queries, admin routes, webhooks, uploads, and AI-generated code. Use when reviewing code that touches user data, PII, or access control.

Why use Sec Check on TypingMind?

Because you install it once and use it with any model. Sec Check is plain Markdown rather than provider-specific code, so the same skill runs on GPT-5, Claude, Gemini, Grok, or a local model — and you can switch model mid-chat without it breaking. TypingMind runs on your own API keys, so you pay providers directly instead of a per-seat subscription, and your skills and chats stay in your own storage.

How do I install Sec Check in TypingMind?

Open Plugins → Skills → Install from GitHub in TypingMind and paste https://github.com/waynesutton/markdown-site/tree/main/.claude/sec-check. TypingMind reads its SKILL.md and installs it as a skill you can enable per chat.

Which AI models can use Sec Check?

Any model you connect in TypingMind. AI skills are plain Markdown instructions rather than provider-specific code, so GPT, Claude, Gemini, Grok, and local models can all load this skill when a request matches it.

How many AI models can I use with Sec Check?

As many as you like. As long as a model supports skills, you can use Sec Check with it — GPT, Claude, Gemini, Grok, DeepSeek, Mistral, Llama and more — all on TypingMind with your own API keys.

Is the Sec Check AI skill free?

Yes. It is published on GitHub by waynesutton under the MIT license. You only pay your own AI provider for the tokens you use.

What are AI skills?

An AI skill is a reusable instruction bundle that teaches an AI model how to do one specific task. It follows the open Agent Skills format: a SKILL.md file with a name and description, plus any scripts, templates or reference files the model may need. The model reads the instructions only when your request matches the skill, so an installed skill costs nothing until it is used.

How are AI skills different from plugins or MCP servers?

A plugin or MCP server gives a model new tools to call — code that runs somewhere and returns a result. An AI skill gives the model knowledge and process instead: how to approach a task, which steps to follow, what good output looks like. Skills are plain Markdown, so they need no server, no API key and no runtime, and they work with any model.

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