codebase-onboarding

codebase-onboarding is a skill for Claude Code, Codex from andreaswasita/copilot-agents-dojo. It costs 14 tokens per session (1,172 once invoked), scanned A, original, MIT.

A repository-surveying process that builds a practical map of an unfamiliar codebase before changes are made. It identifies the language, framework, layout, conventions, entry points, and testing approach.

In plain words
What is it for?
Use it when joining an unfamiliar project, investigating a repository, preparing work for another agent, or deciding where a change belongs.
Why use it?
It reduces the risk of editing the wrong place or breaking project conventions when the codebase is new or poorly documented.

Skill for Claude CodeCodex

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 skills/andreaswasita/copilot-agents-dojo/codebase-onboarding
Any agent
npx skills add andreaswasita/copilot-agents-dojo --skill codebase-onboarding
Clone the repo
git clone --depth 1 https://github.com/andreaswasita/copilot-agents-dojo

Made for: Claude Code, Codex.

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 codebase-onboarding

README.md
[![agentmods](https://agentmods.dev/badge/skills/andreaswasita/copilot-agents-dojo/codebase-onboarding.svg)](https://agentmods.dev/skills/andreaswasita/copilot-agents-dojo/codebase-onboarding)
Your own site
<a href="https://agentmods.dev/skills/andreaswasita/copilot-agents-dojo/codebase-onboarding"><img src="https://agentmods.dev/badge/skills/andreaswasita/copilot-agents-dojo/codebase-onboarding.svg" alt="Measured on agentmods" height="20"></a>
Per session 14 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,172 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 $0.00014 $0.01172
Opus 5 $0.00007 $0.00586
Sonnet 5 $0.00003 $0.00234
Haiku 4.5 $0.00001 $0.00117

Measured 5d ago against content hash 049653b82fa6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 5d 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.

skills/codebase-onboarding/SKILL.md · 118 lines

How it starts

The opening of the file, as written. The whole thing — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Codebase Onboarding Skill

Builds a working mental model of an unfamiliar repository before making changes: language, framework, structure, conventions, entry points, and test pattern. Does NOT exhaustively read every file — surveys strategically, then drills in where the work demands it.

When to Use

  • Working in a new or unfamiliar repository.
  • Before making changes to code you have not read.
  • When a project lacks documentation.
  • User asks you to "look at this repo" or "understand this project".
  • Briefing a sub-agent on context before delegating.
  • NOT when you already have a recent mental model of this repo — re-onboarding wastes turns.

Prerequisites

  • Read access to the repository.
  • The view, grep, and glob Copilot tools.
  • The powershell tool to inspect files outside the source tree (lockfiles, etc.).
  • Ability to run the project's test command (later, optional).

How to Run

1. Survey the top-level layout with `glob`.
2. Read manifest files (package.json, pyproject.toml, go.mod, *.csproj, pom.xml).
3. Read the README.
4. Identify the architecture pattern from directory names.
5. Open the entry point and one representative test.
6. Note conventions: naming, imports, error handling, test layout.
7. Write a short Quick Map (5–10 lines) for your future self.

Quick Reference

Survey target Tool Why
Top-level layout glob '*' Frames the project
Source layout glob 'src/**' (or repo equivalent) Spots architecture pattern
Manifests view package.json / view pyproject.toml Language, framework, scripts
README view README.md Author's intent
Entry point view src/main.* / view cmd/main.go How startup actually works
Tests view one representative test Pattern + framework
Directory signal Architecture clue
src/controllers/ or src/routes/ MVC / route-based
src/features/ or src/modules/ Feature / domain-driven
packages/ or apps/ Monorepo
src/components/ Component-based frontend
cmd/ and internal/ Go standard layout
src/main/java/ Java / Spring
Dockerfile + docker-compose.yml Containerized service set

Read the full file on GitHub · 118 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. 5d ago First seen · 118 lines · 14 tokens per session scan A 049653b82fa6

Subscribe to this mod's changes

codebase-onboarding is a skill published in the GitHub repository andreaswasita/copilot-agents-dojo (51 stars, last pushed 1mo ago), licensed MIT. It adds 14 tokens to every session and 1,172 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.

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