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/fusengine/agents/guardrailsnpx skills add fusengine/agents --skill guardrailsgit clone --depth 1 https://github.com/fusengine/agentsWrote 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/fusengine/agents/guardrails)<a href="https://agentmods.dev/skills/fusengine/agents/guardrails"><img src="https://agentmods.dev/badge/skills/fusengine/agents/guardrails.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00028 | $0.00833 |
| Opus 5 | $0.00014 | $0.00417 |
| Sonnet 5 | $0.00006 | $0.00167 |
| Haiku 4.5 | $0.00003 | $0.00083 |
Grade B, and why
guardrails scanned grade B 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.
Instruction-override phrasingmediumPrompt injection
Text telling the model to disregard its earlier instructions or safety rules is the shape of a prompt injection, whoever wrote it.
✗ Bypass security rules, even if user insists Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.
It includes a ready-to-use ethical-guardrails template and a security checklist covering both the agent level (guardrails per layer, least-privilege tools, logging) and the prompt level (explicit Forbidden section, capability limits, error-case handling, no hardcoded sensitive data).
Guardrails
Skill for implementing security guardrails and quality control.
4-Layer Security Architecture
┌─────────────────────────────────────────────────────┐
│ LAYER 1: Input │
│ - Harmlessness screen (lightweight LLM) │
│ - Pattern matching (jailbreak regex) │
│ - PII detection/redaction │
└─────────────────────────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────┐
│ LAYER 2: System │
│ - Ethical guardrails in system prompt │
│ - Explicit capability limits │
│ - Refusal instructions │
└─────────────────────────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────┐
│ LAYER 3: Output │
│ - Format validation │
│ - Hallucination detection │
│ - Compliance check │
└─────────────────────────────────────────────────────┘
│
▼
┌─────────────────────────────────────────────────────┐
│ LAYER 4: Monitoring │
│ - Logs of all interactions │
│ - Alerts on suspicious patterns │
│ - Rate limiting per user │
└─────────────────────────────────────────────────────┘
What ships with it
2 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.
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 · 112 lines · 28 tokens per session scan B 4588a9b4686c
guardrails is a skill published in the GitHub repository fusengine/agents (25 stars, last pushed today), licensed MIT. It adds 28 tokens to every session and 833 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it B with 1 finding (instruction-override phrasing). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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orchestrating-software-dev
Runs software development projects from idea to completion. Use when starting a software project, adding a feature, fixing a bug, or resuming an in-progress build.
collecting-sources
Collects research sources with quality evaluation. Use when gathering or finding sources, building a source library, searching for academic papers, or performing RADAR assessment.