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.
npx agentmods add skills/usestrix/strix/api-security-testingnpx skills add usestrix/strix --skill api-security-testinggit clone --depth 1 https://github.com/usestrix/strixWhat 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 | $0.00144 | $0.01453 |
| Opus 5 | $0.00072 | $0.00727 |
| Sonnet 5 | $0.00029 | $0.00291 |
| Haiku 4.5 | $0.00014 | $0.00145 |
Grade A, and why
api-security-testing 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 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
`strix_runs/<run>/penetration_test_report.md` first, then `vulnerabilities/*.md` — each contains the exact request that proved the issue. Replay it (for example, with `curl`) before reporting; for authorization findings, How it starts
The opening of the file, as written. The whole thing — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Security-test an API
APIs fail differently from web UIs: there is no rendered surface to crawl, the interesting bugs are authorization-shaped rather than injection-shaped, and the same endpoint behaves differently per token. This workflow targets those specifics with Strix's autonomous agents, using the current OWASP API Security Top 10 (2023) as the coverage checklist. For the web-app equivalent, the current edition is the OWASP Top 10:2025 — see owasp-top-10-testing.
Install, LLM setup, full CLI flags, and the managed-cloud path are in the penetration-testing-with-strix skill. Read it if strix --version fails or the target is not an API.
1. Gather what the agents need
APIs are near-impossible to test blind, so collect first:
| Input | Why it matters |
|---|---|
Schema — OpenAPI/Swagger file, Postman collection, GraphQL endpoint (introspection), or a gRPC .proto |
Turns guesswork into full endpoint enumeration. Biggest single win in coverage. An OpenAPI/Swagger or Postman spec (.json/.yaml/.yml) is a target Strix takes directly; a .proto is not, so pass it with --workspace-file. |
| Two sets of credentials/tokens, ideally in different tenants | BOLA/IDOR — API1:2023, still the #1 API risk — can only be proven by accessing tenant A's objects with tenant B's token. |
| A low-privilege and a high-privilege token | Required to prove broken function-level authorization (API5:2023 — a user calling admin-only routes). |
| Example object IDs | Lets agents test ID tampering immediately instead of hunting for valid identifiers. |
| Out-of-scope routes | Payments, mass notification, destructive admin endpoints. |
| Rate limits / WAF in front of the API | Avoids agents burning budget on throttled requests; mention them so testing adapts. |
Ask the user for anything missing — do not fabricate tokens or scan an API they do not own.
2. Run the scan
Pass the spec as a target, not as prose in the instruction — Strix parses OpenAPI/Swagger (.json/.yaml) and Postman collection exports directly, so the agents start from the real endpoint list:
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.
- yesterday First seen · 62 lines · 144 tokens per session scan A 720eb63825ed
api-security-testing is a skill published in the GitHub repository usestrix/strix (59,426 stars, last pushed 3d ago), licensed Apache-2.0. It adds 144 tokens to every session and 1,453 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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