AuC is a Python framework for running a single AI agent with an asynchronous, pluggable reasoning loop, language-model adapters, permission levels, and observable events. It is used to build coding and conversational agents with tools, security checks, web interfaces, background jobs, evaluations, and isolated execution. The catalogue entries are skills for extending its agent workflow.
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 ufy2024/AuC --skill codebase-onboardinggit clone --depth 1 https://github.com/ufy2024/AuCWrote 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/ufy2024/auc/codebase-onboarding)<a href="https://agentmods.dev/skills/ufy2024/auc/codebase-onboarding"><img src="https://agentmods.dev/badge/skills/ufy2024/auc/codebase-onboarding/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/ufy2024/auc/codebase-onboarding"><img src="https://agentmods.dev/badge/skills/ufy2024/auc/codebase-onboarding.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 3 findings, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Prompt Injection · line 88 Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.Fix: Audit all comments and invisible characters. Remove any instructions that direct the agent to perform unauthorized actions. Use plain, reviewable content.
- medium Agent Snooping · line 21 Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
- medium MCP Rug Pull · line 175 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
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 | $0.00053 | $0.02058 |
| Opus 5.5 | $0.00021 | $0.00823 |
| Sonnet 5.5 | $0.00011 | $0.00412 |
| Haiku 4.5 | $0.00005 | $0.00206 |
Grade A, and why
codebase-onboarding 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.
Copies of this mod
8 near-identical copies found in the catalogue:
- codebase-onboarding — 94% identical, 26 lines differ
- codebase-onboarding — 94% identical, 26 lines differ
- codebase-onboarding — 94% identical, 26 lines differ
- codebase-onboarding — 94% identical, 26 lines differ
- codebase-onboarding — 94% identical, 26 lines differ
- codebase-onboarding — 92% identical, 90 lines differ
- codebase-onboarding — 92% identical, 34 lines differ
- codebase-onboarding — 92% identical, 25 lines differ
How it starts
The opening of the file, as written. The whole thing — 253 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Codebase Onboarding
Systematically analyze an unfamiliar codebase and produce a structured onboarding guide. Designed for developers joining a new project or setting up Claude Code in an existing repo for the first time.
When to Use
- First time opening a project with Claude Code
- Joining a new team or repository
- User asks "help me understand this codebase"
- User asks to generate a CLAUDE.md for a project
- User says "onboard me" or "walk me through this repo"
How It Works
Phase 1: Reconnaissance
Gather raw signals about the project without reading every file. Run these checks in parallel:
1. Package manifest detection
→ package.json, go.mod, Cargo.toml, pyproject.toml, pom.xml, build.gradle,
Gemfile, composer.json, mix.exs, pubspec.yaml
2. Framework fingerprinting
→ next.config.*, nuxt.config.*, angular.json, vite.config.*,
django settings, flask app factory, fastapi main, rails config
3. Entry point identification
→ main.*, index.*, app.*, server.*, cmd/, src/main/
4. Directory structure snapshot
→ Top 2 levels of the directory tree, ignoring node_modules, vendor,
.git, dist, build, __pycache__, .next
5. Config and tooling detection
→ .eslintrc*, .prettierrc*, tsconfig.json, Makefile, Dockerfile,
docker-compose*, .github/workflows/, .env.example, CI configs
6. Test structure detection
→ tests/, test/, __tests__/, *_test.go, *.spec.ts, *.test.js,
pytest.ini, jest.config.*, vitest.config.*
Phase 2: Architecture Mapping
From the reconnaissance data, identify:
Tech Stack
- Language(s) and version constraints
- Framework(s) and major libraries
- Database(s) and ORMs
- Build tools and bundlers
- CI/CD platform
Architecture Pattern
- Monolith, monorepo, microservices, or serverless
- Frontend/backend split or full-stack
- API style: REST, GraphQL, gRPC, tRPC
Key Directories Map the top-level directories to their purpose:
src/components/ → React UI components
src/api/ → API route handlers
src/lib/ → Shared utilities
src/db/ → Database models and migrations
tests/ → Test suites
scripts/ → Build and deployment scripts
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 · 253 lines · 53 tokens per session scan A 8d9a48a742ab
codebase-onboarding is a skill published in the GitHub repository ufy2024/AuC (1,080 stars, last pushed 2mo ago), licensed MIT. It adds 53 tokens to every session and 2,058 once invoked, about $0.0002 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 2026-09-03.
Other skills, from other repositories
hr-onboarding
A new-hire onboarding plan as a single page — first week schedule, buddy + manager intro, learning track, equipment checklist, and "you're set when…" outcomes. Use when the brief mentions "onboarding", "new hire", "first week plan", or "入职".
book-mirror
Take any book (EPUB/PDF), produce a personalized chapter-by-chapter analysis. Each chapter is preserved in detail (The Chapter) and mirrored back to the reader's actual life (The Mirror) using brain context. The mirror observes and resonates — a friend pointing out parallels, NOT a consultant rearranging the reader's…
lean-formalize
Develop and verify a mathematical proof in Lean, continue an incomplete Lean project, or audit whether it proves the original statement. Connect actual inputs to intermediate lemmas, assemble the target theorem, check its transitive axioms, and provide a reproducible handoff. Use when Lean is requested or a specific…
exam-forecast
Analyze past exams from the same professor to surface patterns — subject weighting, recurring issue-spot traps, favored hypo types, policy-vs-doctrine mix — and forecast likely emphases for the upcoming exam. Use when the user says "what's on the exam", "analyze past exams", "predict the exam", or shares past exams.
eli5
Explain research, papers, or technical ideas in plain English with minimal jargon, concrete analogies, and clear takeaways. Use when the user says "ELI5 this", asks for a simple explanation of a paper or research result, wants jargon removed, or asks what something technically dense actually means.
deck-course-module
A course or workshop slide template with persistent learning goals, teaching pages, multiple-choice self-tests, and a wrap-up.