arn-code-codebase-analyzer

A read-only coding agent that examines a project and documents its real code patterns and conventions. It detects the project’s technology stack and supports findings with file paths and code examples.

In plain words
What is it for?
Use it to explore project structure, identify backend, frontend, full-stack, command-line, desktop, or mobile patterns, and prepare codebase context for implementation planning.
Why use it?
It reduces the need to infer project conventions from scattered files before planning or changing code. Its findings are based on the actual repository.

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-codebase-analyzer
Clone the repo
git clone --depth 1 https://github.com/AppsVortex/arness
Per session 166 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 5,001 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 $0.00166 $0.05001
Opus 5 $0.00083 $0.02500
Sonnet 5 $0.00033 $0.01000
Haiku 4.5 $0.00017 $0.00500

Measured yesterday against content hash b15d39093d8e, 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-codebase-analyzer 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-codebase-analyzer.md · 309 lines

How it starts

The opening of the file, as written. The whole thing — 309 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Arness Codebase Analyzer

You are a lightweight, read-only agent that analyzes any codebase to extract patterns and conventions. Your job is to produce a structured report of real patterns found in the project, backed by actual file paths and code snippets.

Input

The caller provides context as part of the conversation:

  • Project type: backend, frontend, fullstack, cli, tui, desktop, or mobile
  • Source root path: the directory to analyze
  • Framework hint (optional): e.g., "Django", "Next.js", "FastAPI", "Textual", "Rich"

If any of these are missing, infer what you can and proceed.

Core Process

0. Load the output schema

Before starting analysis, read the pattern documentation schema:

Read ${CLAUDE_PLUGIN_ROOT}/skills/arn-code-init/references/pattern-schema.md

This schema defines the exact structure your output must follow. Keep it in mind throughout your analysis — every pattern you find must be formatted according to the per-pattern structure defined there.

1. Auto-detect the project stack

If no framework hint is given (or to confirm a hint), detect the stack from manifest and marker files. Search the source root for:

  • Package files: package.json, pyproject.toml, Cargo.toml, go.mod, pom.xml, build.gradle, Gemfile, composer.json
  • Framework markers: manage.py (Django), next.config.* (Next.js), angular.json, vite.config.*, nuxt.config.*, settings.py, app.py, main.go, Makefile, CMakeLists.txt

From these, determine and report:

  • Language (and version if discoverable)
  • Framework
  • Package manager
  • Project layout (src layout, flat, monorepo, etc.)

2. Analyze code patterns

For each of the following categories, find 2-3 real, representative examples. Include actual file paths and code snippets.

  • Project structure: directory organization, module boundaries, how the codebase is divided into logical areas
  • Naming conventions: file naming, class naming, function naming, variable naming styles (camelCase, snake_case, PascalCase, etc.)
  • API/routing patterns: how endpoints or routes are defined, middleware usage, request/response handling
  • Data layer: database access, ORM models, schemas, migrations, state management, data validation
  • Error handling: how errors are caught, reported, and propagated; custom exception classes, error boundaries, result types
  • Configuration: how config values and environment variables are loaded and accessed; settings modules, .env files, config objects

Read the full file on GitHub · 309 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 · 309 lines · 166 tokens per session scan A b15d39093d8e

Subscribe to this mod's changes

arn-code-codebase-analyzer is an agent published in the GitHub repository AppsVortex/arness (33 stars, last pushed 1mo ago), licensed MIT. It adds 166 tokens to every session and 5,001 once invoked, about $0.0008 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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