agent-security

A set of commands for designing security controls for AI agents, including isolation, permissions, protection against instruction-based attacks, and checking generated results.

In plain words
What is it for?
Use it to design agent security architecture, permission boundaries, protections against prompt injection, and output checks.
Why use it?
It helps address the security risks that arise when AI agents can access tools, data, or systems.

Command

Install

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.

agentmods
npx agentmods add commands/tractorjuice/arc-kit/agent-security
Clone the repo
git clone --depth 1 https://github.com/tractorjuice/arc-kit
Per session 16 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,325 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00016 $0.03325
Opus 5 $0.00008 $0.01663
Sonnet 5 $0.00003 $0.00665
Haiku 4.5 $0.00002 $0.00332

Measured 2d ago against content hash 538a92632e3f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-security 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 2d 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.

plugins/arckit-agent-architecture/commands/agent-security.md · 306 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Changes

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.

  1. 2d ago First seen · 306 lines · 16 tokens per session scan A 538a92632e3f

Subscribe to this mod's changes

agent-security is a command published in the GitHub repository tractorjuice/arc-kit (2,208 stars, last pushed 11d ago), with no licence file. It adds 16 tokens to every session and 3,325 once invoked, about $0.0001 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.