What is api-security?

A security testing guide for REST, GraphQL, WebSocket, and web-based large-language-model APIs. It covers how these services receive requests and return data over a network.

Use it to discover endpoints, review API schemas, test access controls and request handling, capture evidence, and process large API descriptions or request collections.

It helps find unauthorized data access, weak rate limits, authentication problems, unsafe queries, and ways an API-integrated AI system could expose data.

api-security — Skill by transilienceai

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/transilienceai/communitytools/api-security

Any agent

npx skills add transilienceai/communitytools --skill api-security

Clone the repo

git clone --depth 1 https://github.com/transilienceai/communitytools

Made for: Claude Code, Codex.

Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 882 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.

Model	Per session	Once invoked
Fable 5	$0.00024	$0.00882
Opus 5	$0.00012	$0.00441
Sonnet 5	$0.00005	$0.00176
Haiku 4.5	$0.00002	$0.00088

Measured 2d ago against content hash e20bd6730a7d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-security 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 2d 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.

skills/api-security/SKILL.md · 47 lines

How it starts

The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.

API Security

Test API endpoints for security vulnerabilities across REST, GraphQL, WebSocket, and LLM-integrated APIs.

Techniques

Type	Key Vectors
GraphQL	Introspection, batching attacks, nested query DoS, field suggestion
REST API	BOLA/IDOR, mass assignment, rate limiting, auth bypass, versioning
WebSocket	Cross-site hijacking, message manipulation, auth flaws
Web-LLM	Prompt injection via API, excessive agency, data exfiltration

Workflow

Discover API endpoints and documentation (Swagger, GraphQL schema)
Map authentication and authorization mechanisms
Test per API type using appropriate techniques
Validate data exposure and access control flaws
Capture evidence with HTTP request/response logs

API at scale (offline corpus / fixture-driven)

For a large or offline API surface — a 2000+ path Swagger, a Postman corpus, a HAR capture — do NOT hand-build the coverage machinery per engagement. Drive it deterministically:

Ingest the corpus → per-endpoint fixtures: python3 tools/fixture_ingest.py <openapi|postman|har> -o fixtures.json normalizes every operation into a request template (method, url with path params filled, sampled body, object_ref for id-like path params, security requirement) and STRIPS baked-in auth (the harness injects tokens). This is what turns a large (thousands-of-operations) OpenAPI/Postman corpus into a resumable matrix instead of an untested pile.
Acquire per-role sessions: via authenticated-session-acquisition (MFA/OTP/SRP → reusable tokens) into the harness's token store.
Replay the per-role authz matrix: python3 tools/auth_replay_harness.py --requests fixtures.json --tokens tokens.json [--proxy <vantage>] replays every endpoint under every role (and cross-tenant), flags BOLA/BFLA where a role got authorized on an object/action it should not, and logs an evidence_id per (endpoint × role). Egress-route via the provisioned vantage for allowlisted APIs.
Protocol-specific authz: OData (odata-deep-authz.md), Cognito (cognito-unauth-and-srp.md), authenticated WebSocket (authenticated-per-role-authz.md).

Read the full file on GitHub · 47 lines

Files

What ships with it

42 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

2d ago First seen · 47 lines · 24 tokens per session scan A e20bd6730a7d

Subscribe to this mod's changes

api-security is a skill published in the GitHub repository transilienceai/communitytools (498 stars, last pushed 1mo ago), licensed MIT. It adds 24 tokens to every session and 882 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.

Code review Security Testing bounty-hunters hackerone pentest pentest-tool security-research

pentester-playwright

Phases 1b/3/4 authorized browser automation — SPA recon, multi-role auth, route/API catalog, PoC screenshots, Evidence landing (scoped proxy). Skill-gate read for web phases. Use when Phase 1b/3/4 web work, JS-rendered SPA, real browser needed, HAR/network capture, or Playwright PoC evidence.

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osint-recon

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pentester-exploit

Phase 4 exploitation — PoC construction, exploit-db/msf search, safe verification. Required Skill-gate read at Phase 4. Use when starting Phase 4, exploitation, exploit, PoC, exploit-db, msf, Metasploit, or payload delivery.

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pentester-recon

Phase 1 intelligence recon methodology — passive+active recon, stack fingerprint, attack-surface map. Required Skill-gate read at Phase 1 (with pentester-enum-services). Use when starting Phase 1, intelligence gathering, recon, reconnaissance, OSINT prep, target profiling, or attack surface mapping.

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pentester-toolkit

Provision the pinned pentest toolset via DotSlash for the current scanenv (host-kali or kali-target-${ID}). Adapter, not a tool wrapper.

fb0sh/pentester · 37 tokens

pentester-waf-bypass

Phase 4 conditional — WAF/filter bypass for authorized CTF/range/pentest when payloads are blocked. Use at Phase 4 if blocked, or when user mentions WAF bypass, filter evasion, SQL/XSS/command-injection bypass, or security filter analysis.

fb0sh/pentester · 64 tokens