security-checklist

security-checklist is a skill for Claude Code from atuljha23/holocron. It costs 36 tokens per session (943 once invoked), scanned A, original, MIT.

A checklist for reviewing common application security risks, including login and permissions, unsafe input, leaked secrets, sessions, encryption, and third-party packages.

In plain words
What is it for?
Use it during code review or before committing changes that handle authentication, user input, sensitive data, or dependencies.
Why use it?
It gives you a consistent set of questions for finding security problems before code is committed.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the holocron plugin — 11 skills, 24 commands, 14 agents, 6 hooks shipped together

Good fit Use it during code review or before committing changes that handle authentication, user input, sensitive data, or dependencies.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/atuljha23/holocron/security-checklist
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 atuljha23/holocron --skill security-checklist
Clone the repo
git clone --depth 1 https://github.com/atuljha23/holocron

Made for: Claude Code.

Or install holocron, the plugin that ships this one along with the rest of its 11 skills, 24 commands, 14 agents, 6 hooks.

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 security-checklist

README.md
[![agentmods](https://agentmods.dev/badge/skills/atuljha23/holocron/security-checklist/github.svg)](https://agentmods.dev/skills/atuljha23/holocron/security-checklist)
Your own site
<a href="https://agentmods.dev/skills/atuljha23/holocron/security-checklist"><img src="https://agentmods.dev/badge/skills/atuljha23/holocron/security-checklist/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 security-checklist

Your own site · 80×15
<a href="https://agentmods.dev/skills/atuljha23/holocron/security-checklist"><img src="https://agentmods.dev/badge/skills/atuljha23/holocron/security-checklist.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 943 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00036 $0.00943
Opus 5 $0.00018 $0.00472
Sonnet 5 $0.00007 $0.00189
Haiku 4.5 $0.00004 $0.00094

Measured 12d ago against content hash 1e9ba6d3e255, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

security-checklist scanned grade A with 1 finding 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.

Runs shell commandslowCapability

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

- [ ] Shell: use argv arrays, never `exec(string)` with user input. Use a safe runner (`execFile`, `subprocess.run([...])`).
skills/security-checklist/SKILL.md · 78 lines

How it starts

The opening of the file, as written. The whole thing — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security checklist

Authn / authz

  • Authentication check happens on a path the caller can't influence (verified JWT, session cookie with HttpOnly/Secure/SameSite).
  • Authorization is explicit in the handler, not implied by routing.
  • Role/permission decisions use the server's identity model, never a client-supplied header.
  • Multi-tenant check: the resource belongs to the caller's tenant (not just the caller's user).
  • No IDOR: object IDs in URLs are checked against ownership, not just existence.

Input validation

  • Validated at the edge (handler/controller), not deep in services.
  • Schema-based where possible (zod/pydantic/struct tags).
  • Every sink is aware of the shape feeding it (SQL parameters, shell args, template context, file paths, HTTP URLs, deserializers).

Injection surfaces

  • SQL: parameters only. Never string-concat into a query.
  • Shell: use argv arrays, never exec(string) with user input. Use a safe runner (execFile, subprocess.run([...])).
  • Path: reject .., absolute paths, and symlinks that escape the allowed root.
  • Template: auto-escape on; avoid raw/|safe; parameterize over string assembly.
  • Deserializers: never pickle/yaml.load/eval on untrusted input.
  • HTML rendering: sanitize + use a framework that auto-escapes; beware dangerouslySetInnerHTML.

Secrets

  • Not in source.
  • Not logged. Scrub before logging (redact keys like password, token, secret, auth).
  • Read from env or a secrets manager.
  • Rotated when in doubt.

Sessions / cookies

  • HttpOnly, Secure, SameSite=Lax (or Strict when tighter is fine).
  • Session rotates on privilege change (login, logout, role change).
  • Logout invalidates server-side, not just client-side.

Crypto

  • Use the platform library. Never roll your own.
  • MD5 / SHA-1 are NOT for security. Use SHA-256+, bcrypt/argon2 for passwords.
  • Encryption in authenticated mode (AES-GCM), never ECB.
  • RNG: cryptographic (crypto.randomBytes / secrets.token_*), never Math.random.
  • Secrets compared in constant time where applicable.

Read the full file on GitHub · 78 lines

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. 12d ago First seen · 78 lines · 36 tokens per session scan A 1e9ba6d3e255

Subscribe to this mod's changes

security-checklist is a skill published in the GitHub repository atuljha23/holocron (2 stars, last pushed 4mo ago), licensed MIT. It adds 36 tokens to every session and 943 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (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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