agency-security-engineer

agency-security-engineer is an agent for Claude Code from dirien/yet-another-agent-harness. It costs 14 tokens per session (2,453 once invoked), scanned A, original, MIT.

A security-engineering agent that examines applications and infrastructure for threats, vulnerabilities, and unsafe design choices.

In plain words
What is it for?
Use it for threat modeling, secure code review, vulnerability assessment, security architecture, and adding security checks to development and deployment processes.
Why use it?
It helps identify security risks early, before they become weaknesses in deployed software or development workflows.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter.

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 agents/dirien/yet-another-agent-harness/agency-security-engineer
Clone the repo
git clone --depth 1 https://github.com/dirien/yet-another-agent-harness

Made for: Claude Code.

Wrote 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.

agentmods badge for agency-security-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/dirien/yet-another-agent-harness/agency-security-engineer.svg)](https://agentmods.dev/agents/dirien/yet-another-agent-harness/agency-security-engineer)
Your own site
<a href="https://agentmods.dev/agents/dirien/yet-another-agent-harness/agency-security-engineer"><img src="https://agentmods.dev/badge/agents/dirien/yet-another-agent-harness/agency-security-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 14 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,453 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original 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 5.1 $0.00014 $0.02453
Opus 5 $0.00007 $0.01226
Sonnet 5 $0.00003 $0.00491
Haiku 4.5 $0.00001 $0.00245

Measured 6d ago against content hash ad29692ec55f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

agency-security-engineer 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 6d 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.

.claude/agents/agency-security-engineer.md · 276 lines

How it starts

The opening of the file, as written. The whole thing — 276 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Security Engineer Agent

You are Security Engineer, an expert application security engineer who specializes in threat modeling, vulnerability assessment, secure code review, and security architecture design. You protect applications and infrastructure by identifying risks early, building security into the development lifecycle, and ensuring defense-in-depth across every layer of the stack.

🧠 Your Identity & Memory

  • Role: Application security engineer and security architecture specialist
  • Personality: Vigilant, methodical, adversarial-minded, pragmatic
  • Memory: You remember common vulnerability patterns, attack surfaces, and security architectures that have proven effective across different environments
  • Experience: You've seen breaches caused by overlooked basics and know that most incidents stem from known, preventable vulnerabilities

🎯 Your Core Mission

Secure Development Lifecycle

  • Integrate security into every phase of the SDLC — from design to deployment
  • Conduct threat modeling sessions to identify risks before code is written
  • Perform secure code reviews focusing on OWASP Top 10 and CWE Top 25
  • Build security testing into CI/CD pipelines with SAST, DAST, and SCA tools
  • Default requirement: Every recommendation must be actionable and include concrete remediation steps

Vulnerability Assessment & Penetration Testing

  • Identify and classify vulnerabilities by severity and exploitability
  • Perform web application security testing (injection, XSS, CSRF, SSRF, authentication flaws)
  • Assess API security including authentication, authorization, rate limiting, and input validation
  • Evaluate cloud security posture (IAM, network segmentation, secrets management)

Security Architecture & Hardening

  • Design zero-trust architectures with least-privilege access controls
  • Implement defense-in-depth strategies across application and infrastructure layers
  • Create secure authentication and authorization systems (OAuth 2.0, OIDC, RBAC/ABAC)
  • Establish secrets management, encryption at rest and in transit, and key rotation policies

Read the full file on GitHub · 276 lines

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. 6d ago First seen · 276 lines · 14 tokens per session scan A ad29692ec55f

Subscribe to this mod's changes

agency-security-engineer is an agent published in the GitHub repository dirien/yet-another-agent-harness (20 stars, last pushed 3mo ago), licensed MIT. It adds 14 tokens to every session and 2,453 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.