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/web-app-penetration-testingnpx skills add usestrix/strix --skill web-app-penetration-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 | $0.00129 | $0.00958 |
| Opus 5 | $0.00064 | $0.00479 |
| Sonnet 5 | $0.00026 | $0.00192 |
| Haiku 4.5 | $0.00013 | $0.00096 |
Grade A, and why
web-app-penetration-testing 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 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.
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.
How it starts
The opening of the file, as written. The whole thing — 55 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Pentest a web application
Black-box (and optionally source-assisted) penetration testing of a running web app with Strix's autonomous agents. Every reported finding is validated with a working exploit, so there are no signature-based false positives to triage.
Install, LLM setup, all CLI flags, and the managed-cloud alternative are covered in the penetration-testing-with-strix skill — read it if the target is not a running web app, or if strix --version fails. This skill is the web-app-specific workflow.
1. Confirm authorization and scope
Before running anything, establish:
- The target is the user's (or they are explicitly authorized to test it). Never pentest a third-party site on a hunch.
- Which environment. Prefer staging over production; agents send real exploit payloads and will create/modify data.
- Out-of-scope paths — payment flows, mass-email endpoints, admin destructive actions, third-party SSO providers.
- Credentials. Most real vulnerabilities live behind login. Without a test account, the agents only ever see the marketing surface.
Ask for anything missing rather than guessing.
2. Run the scan
strix -n -t https://staging.example.com --max-budget 20 \
--instruction "Test account: [email protected] / <password>. In scope: /app/*, /api/*. Do not touch /billing or send email. Focus on access control between the two seeded orgs."
Notes that matter for web apps specifically:
- Give it credentials via
--instruction(or--instruction-filefor anything long), including how to log in if the flow is unusual (magic link, SSO, MFA-exempt test user). - Two accounts beat one. Multi-tenant IDOR and broken-access-control bugs — consistently the highest-impact class in web apps — can only be proven when the agent can attempt cross-account access.
- Add the repo for white-box depth when you have the source:
-t https://github.com/org/app -t https://staging.example.com(or a local path). Source access materially improves coverage of business-logic and authorization flaws. - Localhost works. Point at
http://host.docker.internal:3000(Docker Desktop) so the sandbox can reach a dev server on the host. --scan-mode quickfor a fast dev-loop pass,standard(~30 min) for a normal review,deepfor pre-release assurance. Always set--max-budget.
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 · 55 lines · 129 tokens per session scan A 7b345118ed8e
web-app-penetration-testing is a skill published in the GitHub repository usestrix/strix (59,426 stars, last pushed 3d ago), licensed Apache-2.0. It adds 129 tokens to every session and 958 once invoked, about $0.0006 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.
Other skills, from other repositories
cis-aws-foundations-3.2.3
Ensure that RDS instances are not publicly accessible.
cis-aws-foundations-2.14
Ensure IAM policies that allow full ":" administrative privileges are not attached.
cis-aws-foundations-3.2.1
Ensure that encryption-at-rest is enabled for RDS instances.
cis-aws-foundations-3.3.1
Ensure that encryption is enabled for EFS file systems.
cis-aws-foundations-4.1
Ensure CloudTrail is enabled in all regions.
cis-aws-foundations-4.3
Ensure AWS Config is enabled in all regions.