SAST Skills is a collection of agent workflows that inspect web and mobile application code for security vulnerabilities, where SAST means static application security testing. Developers and security reviewers use it to map a codebase, verify possible flaws, and produce a severity-ranked remediation report. The catalogue entries are the project's vulnerability-detection and reporting skills.
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 skills add utkusen/sast-skills --skill sast-sstigit clone --depth 1 https://github.com/utkusen/sast-skillsWrote 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.
[](https://agentmods.dev/skills/utkusen/sast-skills/sast-ssti)<a href="https://agentmods.dev/skills/utkusen/sast-skills/sast-ssti"><img src="https://agentmods.dev/badge/skills/utkusen/sast-skills/sast-ssti/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/utkusen/sast-skills/sast-ssti"><img src="https://agentmods.dev/badge/skills/utkusen/sast-skills/sast-ssti.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Excessive Agency · line 64 Skill grants unrestricted tool access without appropriate constraints. An agent with unfettered tool access can perform arbitrary actions including file modification, network requests, and code execution.Fix: Restrict tool access to only the tools required for the skill's stated purpose. Use an explicit allowlist rather than granting blanket access.
- medium Excessive Agency · line 90 Skill grants unrestricted tool access without appropriate constraints. An agent with unfettered tool access can perform arbitrary actions including file modification, network requests, and code execution.Fix: Restrict tool access to only the tools required for the skill's stated purpose. Use an explicit allowlist rather than granting blanket access.
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 5.1 | $0.00099 | $0.07571 |
| Opus 5 | $0.00049 | $0.03785 |
| Sonnet 5 | $0.00020 | $0.01514 |
| Haiku 4.5 | $0.00010 | $0.00757 |
Grade A, and why
sast-ssti scanned grade A with 2 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 12d 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.
Unrestricted tool accesslowExcessive agency
A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.
- **Sandboxed template engines configured with a restricted environment**: Liquid, Mustache, and similar logic-less engines cannot execute arbitrary code even if the template string comes from user input — but still flag Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
Runs shell commandslowCapability
Expected in a hook, worth knowing in a rule or an instructions file.
// Payload: ?template=<%- global.process.mainModule.require('child_process').execSync('id') %> Copies of this mod
1 near-identical copy found in the catalogue:
- sast-ssti — 86% identical, 99 lines differ
How it starts
The opening of the file, as written. The whole thing — 607 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Server-Side Template Injection (SSTI) Detection
You are performing a focused security assessment to find Server-Side Template Injection vulnerabilities in a codebase. This skill uses a three-phase approach with subagents: recon (find candidate rendering sites where the template string is dynamic), batched verify (trace whether user input reaches each site's template argument, in parallel batches of 3), and merge (consolidate batch results into the final report).
Prerequisites: sast/architecture.md must exist. Run the analysis skill first if it doesn't.
What is SSTI
Server-Side Template Injection occurs when user-supplied input is embedded directly into a template string that is then evaluated by a template engine. Unlike passing user data as context variables to a static template, SSTI means the user can write template syntax that the engine will execute — leading to arbitrary code execution, file read, or full server compromise.
The core pattern: unvalidated user input is used as the template string passed to a template engine's render/compile/evaluate function.
What SSTI IS
- Passing user input as the template string to be compiled or rendered:
Template(user_input).render()— Jinja2env.from_string(user_input).render()— Jinja2render_template_string(user_input)— Flaskejs.render(user_input, ctx)— EJS (Node.js)nunjucks.renderString(user_input, ctx)— NunjucksHandlebars.compile(user_input)(ctx)— Handlebarspug.render(user_input, ctx)— Pug/Jade_.template(user_input)(ctx)— Lodash/UnderscoreVelocity.evaluate(ctx, user_input)— Apache Velocity (Java)new Template("anon", new StringReader(user_input), cfg).process(...)— FreeMarker (Java)new ST(user_input).render()— StringTemplate4 (Java)thymeleafEngine.process(user_input, ctx)— Thymeleaf (Java)\Twig\Environment::createTemplate(user_input)->render(ctx)— Twig (PHP)$smarty->fetch("string:" . user_input)— Smarty (PHP)Liquid::Template.parse(user_input).render(ctx)— Liquid (Ruby)ERB.new(user_input).result(binding)— ERB (Ruby)t, _ := template.New("x").Parse(user_input); t.Execute(w, data)— Gotext/templateTemplate.fromString(user_input).render(ctx)— Pebble (Java)
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.
- 12d ago First seen · 607 lines · 99 tokens per session scan A b3c4a6e6b5ed
sast-ssti is a skill published in the GitHub repository utkusen/sast-skills (1,309 stars, last pushed 5mo ago), licensed MIT. It adds 99 tokens to every session and 7,571 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 2 findings (unrestricted tool access, runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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