Actual-sync: Skill for Claude Code

.claude/skills/owasp-api-security/SKILL.md

owasp-api-security is a skill for Claude Code from agigante80/Actual-sync. It costs 48 tokens per session (5,385 once invoked), scanned B, original, MIT.

A security-testing guide for REST APIs, which are web endpoints that exchange data over HTTP. It follows the OWASP API Security Top 10, a list of common API risks, and targets the described Express application.

In plain words
What is it for?
Use it to review API endpoints, create security tests, and test protected and public routes with the application's authentication and database setup.
Why use it?
It provides concrete checks for weak authentication, injection, input validation, and other API vulnerabilities instead of relying only on ordinary functional tests.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is agigante80/Actual-sync's own configuration. It tells Claude Code how to work on Actual-sync itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Actual-sync configures →

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is '../../../etc/passwd',.

Reuse

Borrowing it

Nothing to install: this file belongs to agigante80/Actual-sync. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/agigante80/Actual-sync/main/.claude/skills/owasp-api-security/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/agigante80/Actual-sync

Made for: Claude Code.

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 owasp-api-security

README.md
[![agentmods](https://agentmods.dev/badge/skills/agigante80/actual-sync/owasp-api-security.svg)](https://agentmods.dev/skills/agigante80/actual-sync/owasp-api-security)
Your own site
<a href="https://agentmods.dev/skills/agigante80/actual-sync/owasp-api-security"><img src="https://agentmods.dev/badge/skills/agigante80/actual-sync/owasp-api-security.svg" alt="Measured on agentmods" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,385 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 5.1 $0.00048 $0.05385
Opus 5 $0.00024 $0.02693
Sonnet 5 $0.00010 $0.01077
Haiku 4.5 $0.00005 $0.00539

Measured yesterday against content hash cb111034e3d6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade B, and why

owasp-api-security scanned grade B 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 yesterday.

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.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

server: 'http://169.254.169.254/latest/meta-data/' // cloud metadata SSRF target

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

.claude/skills/owasp-api-security/SKILL.md · 437 lines

How it starts

The opening of the file, as written. The whole thing — 437 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OWASP API Security Testing

Comprehensive security testing knowledge base for REST APIs, aligned with OWASP API Security Top 10:2023 and OWASP ASVS 5.0, adapted to Actual-sync's real stack.

Stack the examples target

Actual-sync exposes one Express HTTP surface from src/services/healthCheck.js:

  • Server: Express app started via http.createServer(this.app) on a configurable port. Tests start the real server and hit it with Node's built-in http module — not fastify.inject(), not supertest. See src/__tests__/healthCheck.test.js for the idiom.
  • Auth: HTTP Basic auth (or Bearer token) via dashboardAuth(), realm "Dashboard". Unauthenticated/invalid Basic → 401 with a WWW-Authenticate: Basic realm="Dashboard" header. There is one admin credential pair (dashboardConfig.auth.username/password), not per-user sessions.
  • Protected surface (behind dashboardAuth()): /dashboard and /api/dashboard/* (status, servers, orphaned-servers, schedules, metrics, history, accounts, plus POST sync, dismiss-error, reset-history, test-notification).
  • Public surface (no auth by design): /health, /ready, /metrics, /metrics/prometheus, /icon.png, and the WebSocket log stream /ws/logs.
  • Validation: AJV against config/config.schema.json at startup; request-body validation is hand-rolled in the route handlers. There is no Zod.
  • DB: better-sqlite3 with ?-parameterized prepared statements (services/syncHistory.js).
  • Rate limiting: express-rate-limit (60 req/min/IP, /icon.png exempt).
  • Logging: the custom logger in src/lib/logger.js auto-redacts secrets before writing — error responses must redact too (they are a separate egress path).

When to Use This Skill

  • Writing security tests for the dashboard API endpoints
  • Reviewing /api/dashboard/* routes for OWASP vulnerabilities
  • Generating injection/fuzzing payloads for test suites
  • Auditing the single-admin auth gate (dashboardAuth())
  • Validating that responses never leak secrets (passwords, tokens, encryptionPassword) or stack traces
  • Assessing rate limiting and resource-exhaustion protections

Read the full file on GitHub · 437 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. yesterday First seen · 437 lines · 48 tokens per session scan B cb111034e3d6

Subscribe to this mod's changes

owasp-api-security is a skill published in the GitHub repository agigante80/Actual-sync (12 stars, last pushed 3d ago), licensed MIT. It adds 48 tokens to every session and 5,385 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it B with 1 finding (cloud metadata endpoint). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-04.