security-conventions

security-conventions is a skill for Claude Code, Codex from fpindej/netrock. It costs 19 tokens per session (871 once invoked), scanned A, original, MIT.

A security checklist for an application using login sessions, permissions, cookies, request protection, and browser security policies.

In plain words
What is it for?
Use it when reviewing authentication, permissions, refresh tokens, data masking, request validation, uploads, URLs, and content-security settings.
Why use it?
It gives security-focused reviews concrete checks for unauthorized access, unsafe input, token handling, personal data exposure, and risky file or URL inputs.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/fpindej/netrock/security-conventions
Any agent
npx skills add fpindej/netrock --skill security-conventions
Clone the repo
git clone --depth 1 https://github.com/fpindej/netrock

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 security-conventions

README.md
[![agentmods](https://agentmods.dev/badge/skills/fpindej/netrock/security-conventions.svg)](https://agentmods.dev/skills/fpindej/netrock/security-conventions)
Your own site
<a href="https://agentmods.dev/skills/fpindej/netrock/security-conventions"><img src="https://agentmods.dev/badge/skills/fpindej/netrock/security-conventions.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 871 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00019 $0.00871
Opus 5 $0.00010 $0.00436
Sonnet 5 $0.00004 $0.00174
Haiku 4.5 $0.00002 $0.00087

Measured 4d ago against content hash ace2755ca768, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

security-conventions 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 4d 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.

.claude/skills/security-conventions/SKILL.md · 80 lines

How it starts

The opening of the file, as written. The whole thing — 80 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Conventions

Architecture Context

  • JWT access tokens in HttpOnly cookies, refresh token rotation
  • Permission-based authorization via [RequirePermission] attributes
  • Role hierarchy: Superuser > Admin > User > Custom
  • PII masking server-side via PiiMasker / WithMaskedPii - requires users.view_pii permission
  • CSRF protection via Origin header validation on mutations
  • CSP with nonce-based script-src
  • API proxy in SvelteKit forwards cookies + headers

Security Checklist

Authentication & Authorization

  • Auth middleware cannot be bypassed (no unprotected routes that should be protected)
  • [RequirePermission] on every action that needs it - not just [Authorize]
  • Role hierarchy enforced - cannot manage users at/above your rank
  • Cannot modify your own roles, lock yourself, or delete yourself
  • Refresh token rotation works correctly - old tokens invalidated
  • Permission changes invalidate affected users' tokens and cache

Input Validation

  • All input validated on backend (FluentValidation) - frontend validation is UX only
  • File uploads: size limits, MIME type validation, no path traversal
  • URL fields: restrict to http/https schemes via Uri.TryCreate
  • SQL injection: parameterized queries only (EF Core handles this, but check raw SQL)
  • No string interpolation in LINQ/SQL queries
  • Rate limiting on auth endpoints and mutations

PII Compliance

  • Emails, phone numbers, usernames never exposed without users.view_pii permission
  • PII masking happens server-side - never rely on frontend
  • No PII in logs (structured logging with masking)
  • No PII in URLs, tokens, or error messages
  • Self-view exemption: users see their own unmasked data
  • Audit trail for PII access

Information Leakage

  • Error messages use ErrorMessages.* constants - no stack traces, no internal details
  • ProblemDetails for all error responses - no anonymous objects
  • Identity errors: log .Description server-side, return static message to client
  • No sensitive data in JWT claims beyond what's needed
  • SetDbStatementForText never set to true in OTEL (captures SQL with PII)
  • appsettings.Development.json and appsettings.Testing.json excluded from publish

Read the full file on GitHub · 80 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. 4d ago First seen · 80 lines · 19 tokens per session scan A ace2755ca768

Subscribe to this mod's changes

security-conventions is a skill published in the GitHub repository fpindej/netrock (231 stars, last pushed 5d ago), licensed MIT. It adds 19 tokens to every session and 871 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.