API Security Engineer AI Skill - Sibylla
Secure your APIs where they actually break: authorization per object, a real endpoint inventory, and gateway and CI controls that hold.
Claude skill package instant downloadsibylla-api-security-engineer.skill
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Example
You: We have 300 endpoints, no inventory, and a scanner that finds nothing. Where are we actually exposed?
AI: Sibylla returns an endpoint inventory approach with the shadow and zombie findings, an authorization test plan targeting BOLA and function-level flaws by object type, ...
This is not an app. It's an expert you add to your own AI.
Included in your plan
Ask your AI for it by name, or pick it in your dashboard. No need to buy the file.
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// the file itself
The first lines of the file your AI will read, exactly as delivered. Nothing rewritten for the page.
You are Sibylla, an API Security Engineer who tests object level authorisation from a second account, reconciles the endpoint inventory against live traffic, and validates every JWT claim. You have been activated to secure the interfaces your platform exposes.
// what's inside
Product and platform teams shipping APIs fast who need authorization and inventory under control before someone enumerates their object IDs.
// two ways to get it
$12/mo cancel anytime, or $99 a year
$19 one payment
Already on Library or Both? This one is included, no need to buy the file.
// ask your assistant
Go to kissmyskills.com/pages/connector and set up the "API Security Engineer AI Skill - Sibylla" skill (handle: sibylla-api-security-engineer) for me
Paste it into Claude, ChatGPT, Claude Code, Cursor or Codex. Your AI walks you through connecting KissMySkills (about 3 minutes, 7-day free trial) and loads the skill. What your AI will read →
Drop Sibylla into Claude and get an API security engineer who goes straight for broken object level authorization, because that is what is actually getting exploited.
Sibylla secures APIs as their own attack surface: the OWASP API Security Top 10 with BOLA and broken function-level authorization treated as the dominant real-world findings, API discovery and inventory including shadow, zombie and undocumented endpoints, schema and contract validation across OpenAPI, GraphQL and gRPC, authentication and authorization done properly with OAuth 2.0 grant selection, OIDC, JWT validation failures, scopes versus entitlements, token lifetime and revocation and mTLS for service-to-service, rate limiting and abuse prevention, gateway and WAAP policy on Kong, Apigee, AWS API Gateway and Cloudflare, mass assignment and excessive data exposure, webhook and callback security, machine-to-machine credentials, business logic abuse no scanner will find, API testing in CI and in production, and the third-party API you consume being your problem too.
What you get
How to install
Download the .skill package, open Claude, paste SKILL.md into your Project Instructions or system prompt, describe your requirement, and Sibylla builds the answer. Includes a full worked example so you see exactly what you get.
After checkout, the download link lands in your inbox. Save the .skill file: Claude takes it as it is.
Any AI chat you already use: Claude, ChatGPT, Gemini, Grok, Copilot or another.
Claude: turn on code execution in Settings → Capabilities, then Customize → Skills → + → Create skill → Upload a skill and pick the .skill file. ChatGPT, Gemini and others: open the .skill file like a .zip archive and paste SKILL.md into custom instructions or Project instructions.
Your AI is now configured as a specialist. Ask it anything inside its domain.
No technical knowledge required.
Secure your APIs where they actually break: authorization per object, a real endpoint inventory, and gateway and CI controls that hold. Load it once into Claude Projects and you get a configured API Security Engineer without re-explaining context at the start of every session. This skill is for authorized, defensive security work only. Validate findings in your own environment, follow your rules of engagement and written authorization, and confirm current framework, vendor, and regulatory specifics before you act on them.
Download the .skill package (it contains SKILL.md), then, in Claude, turn on code execution in Settings → Capabilities and add it under Customize → Skills → + → Create skill → Upload a skill (in ChatGPT, Gemini or another AI, open it as a .zip and paste SKILL.md into Project instructions or custom instructions), add your own context and start your first session. Works with Claude, ChatGPT, or any AI chat that accepts system prompts.
Works with Claude (recommended), ChatGPT, Gemini, Perplexity and Copilot, and any AI chat that accepts system prompts. Claude Projects gives the best results.
Without a skill file your AI starts every session as a general assistant. With Sibylla loaded it applies API Security Engineer methodology from the first message, with consistent quality every time. This skill is for authorized, defensive security work only. Validate findings in your own environment, follow your rules of engagement and written authorization, and confirm current framework, vendor, and regulatory specifics before you act on them.
This one and 2,500+ others, inside Claude, ChatGPT, Claude Code, Codex or Cursor. Cancel anytime.
7 days free, every skill