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 UnboundCompute/security-agent-skills --skill auditing-the-lethal-trifectagit clone --depth 1 https://github.com/UnboundCompute/security-agent-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/unboundcompute/security-agent-skills/auditing-the-lethal-trifecta)<a href="https://agentmods.dev/skills/unboundcompute/security-agent-skills/auditing-the-lethal-trifecta"><img src="https://agentmods.dev/badge/skills/unboundcompute/security-agent-skills/auditing-the-lethal-trifecta/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/unboundcompute/security-agent-skills/auditing-the-lethal-trifecta"><img src="https://agentmods.dev/badge/skills/unboundcompute/security-agent-skills/auditing-the-lethal-trifecta.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00119 | $0.01490 |
| Opus 5.5 | $0.00048 | $0.00596 |
| Sonnet 5.5 | $0.00024 | $0.00298 |
| Haiku 4.5 | $0.00012 | $0.00149 |
Grade A, and why
auditing-the-lethal-trifecta 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Auditing the lethal trifecta: the agent exposure condition
An AI agent turns dangerous when three capabilities share one trust context:
- Private data. It can read secrets, user data, internal systems.
- Untrusted content. It ingests text an attacker can influence.
- Exfiltration. It can send data somewhere the attacker can observe.
Any two of these are usually safe. All three together mean an attacker who plants content can make the agent read the private data and route it out, no account takeover required. The trifecta is a structural property of the agent's wiring, which is why it survives prompt-level defenses that a specific payload would slip.
When to use
- You are designing or reviewing a tool-using agent, assistant, or automation.
- Before granting the agent a new tool, data scope, or network capability.
- You found a prompt injection and need to know if it can cause real damage.
- You are writing or reviewing an agent's permission and egress posture.
Scope check
Audit agents and systems you own or are authorized to test. Do not plant content in or exfiltrate from systems you do not control. If you can't name the authorization, stop.
The loop
-
Fix the trust context. A context is one session, task, or conversation where content and capabilities mix, sharing the same model instance and memory. The trifecta must co-occur within a single context to bite; audit context by context, not tool by tool.
-
Inventory capabilities. List everything the agent can read and everything it can do in this context: data stores, credentials, files, internal APIs, network calls, message/PR/email sends, tool invocations, memory writes.
-
Label each against the three legs. Mark every capability as private-data (leg A), untrusted-content intake (leg B), or exfiltration/egress (leg C). Be honest about indirect legs: a tool that writes to a shared doc an attacker can read is egress; a "read-only" web fetch is untrusted-content intake.
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.
- 1mo ago First seen · 125 lines · 119 tokens per session scan A 0de5d6f2a9ca
auditing-the-lethal-trifecta is a skill published in the GitHub repository UnboundCompute/security-agent-skills (5 stars, last pushed 1mo ago), licensed MIT. It adds 119 tokens to every session and 1,490 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-09-05.
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