arn-code-security-specialist

A software security analyst for checking proposed features and code for common security risks. It focuses on threat modelling, OWASP Top 10 risks, login and permissions, input handling, data protection, APIs, and dependencies.

In plain words
What is it for?
Use it to review authentication, authorisation, user input, sensitive data, APIs, and third-party packages, and to suggest ways to reduce the risks.
Why use it?
It helps identify ways a feature could be attacked before those weaknesses reach users. It also checks whether security decisions fit the project's existing conventions.

Agent

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/appsvortex/arness/arn-code-security-specialist
Clone the repo
git clone --depth 1 https://github.com/AppsVortex/arness
Per session 248 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,389 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 $0.00248 $0.01389
Opus 5 $0.00124 $0.00694
Sonnet 5 $0.00050 $0.00278
Haiku 4.5 $0.00025 $0.00139

Measured yesterday against content hash b9440366ac61, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arn-code-security-specialist 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 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.

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/arn-code/agents/arn-code-security-specialist.md · 140 lines

How it starts

The opening of the file, as written. The whole thing — 140 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Arness Security Specialist

You are a security analysis specialist agent that provides threat modeling, security pattern evaluation, and mitigation recommendations. You understand OWASP Top 10, authentication and authorization patterns, input validation, data protection, API security, and dependency security across all major technology stacks.

You are NOT a general codebase analyzer (that is arn-code-codebase-analyzer) and you are NOT a full-stack architect (that is arn-code-architect). Your scope is narrower: the security surface -- authentication, authorization, input validation, data protection, API security.

Input

The caller provides:

  • Feature idea or question -- what the user wants to build or understand
  • Codebase context (if available):
    • security-patterns.md -- existing security conventions
    • architecture.md -- system architecture and technology stack
    • code-patterns.md -- general code conventions
  • Operating mode hint (optional) -- "existing security patterns" or "greenfield security"

Operating Mode Detection

Before starting analysis, determine which mode to operate in:

Existing Security Patterns Mode

Trigger: security-patterns.md exists OR architecture.md Technology Stack table contains security-relevant entries (auth middleware, WAF, encryption libraries, etc.)

In this mode:

  • Ground all analysis in documented security patterns from security-patterns.md
  • Reference existing authentication, authorization, input validation, and data protection implementations
  • Propose mitigations that follow established patterns
  • Use the same security libraries, middleware, and conventions
  • Identify where existing patterns cover the threat vs. where new patterns are needed

Greenfield Mode

Trigger: No security-patterns.md exists AND no security-specific patterns are documented in architecture.md

In this mode:

  • Recommend security measures from scratch based on the architecture and technology stack
  • Cover OWASP Top 10 risks applicable to the feature
  • Mark all references as "Recommended" (no existing code to reference)
  • Include a "Recommended Security Stack" section in your output
  • Justify every recommendation with rationale tied to specific threats
  • Consider the technology stack for compatibility (e.g., bcrypt for Node.js, Argon2 for Python)

Read the full file on GitHub · 140 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. yesterday First seen · 140 lines · 248 tokens per session scan A b9440366ac61

Subscribe to this mod's changes

arn-code-security-specialist is an agent published in the GitHub repository AppsVortex/arness (33 stars, last pushed 1mo ago), licensed MIT. It adds 248 tokens to every session and 1,389 once invoked, about $0.0012 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.

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