Best codebase onboarding skills for Claude Code, Codex and other agents.

Answers questions about a codebase by searching a prebuilt knowledge graph of its files, functions, classes and dependencies, not by rereading every source file.

Egonex-AI/Understand-Anything

Gives an in-depth explanation of one file, function or module by reading the project's knowledge graph and checking that the graph is still fresh.

Egonex-AI/Understand-Anything

Packs a local or remote repository into a single AI-friendly file with the Repomix CLI, then reads and searches that output to explain structure, find patterns or report metrics.

yamadashy/repomix

Turns a codebase into an interactive single-page HTML course for non-technical learners, with scroll modules, animated diagrams, quizzes and plain-English code translations.

zarazhangrui/codebase-to-course

Extracts business domains, flows and process steps from a codebase and produces an interactive horizontal flow graph, reusing an existing knowledge graph when one exists.

Egonex-AI/Understand-Anything

Build or update an interactive isometric map of a repository's architecture — buildings sized by real measurements, neighborhoods by subsystem, animated flows tracing actual call paths, and a drift…

almendili/skills

Writes an onboarding guide for new team members from a project's existing knowledge graph, after checking that the graph still matches the current commit.

Egonex-AI/Understand-Anything

Semantic code search and index management with the ccc CLI: the agent initializes, indexes and queries the project by concept, filtering by language or path.

cocoindex-io/cocoindex-code

Explore and understand codebases using SocratiCode semantic search, dependency graphs, and context artifacts.

giancarloerra/SocratiCode

AI-powered Rust documentation generation engine for comprehensive codebase analysis, C4 architecture diagrams, and automated technical documentation.

sopaco/deepwiki-rs

Explains the architecture of a public GitHub repository through GitDiagram: how the code is organized, the main components with paths, and a Mermaid diagram.

ahmedkhaleel2004/gitdiagram

Navigates a codebase through the code-review-graph MCP tools: architecture overview, symbol search, caller and callee tracing, flows and oversized functions.

tirth8205/code-review-graph

Use CodeGraphContext (CGC) to index a repo into a graph DB and query it via CLI or MCP.

CodeGraphContext/CodeGraphContext

Packs a local directory or remote GitHub repository into one AI-friendly file with Repomix, then searches it to explore structure, find patterns and count tokens.

yamadashy/repomix

Generates Mermaid diagrams from Trailmark code graphs, including call graphs, class hierarchies, module dependency maps, complexity heatmaps and attack surface data flows.

trailofbits/skills

Maps an unfamiliar codebase into seven evidence-backed documents in docs/codebase/, using a scan script and templates, for onboarding or architecture write-ups.

github/awesome-copilot

Explains how a public GitHub repository is built by fetching its GitDiagram architecture diagram, components and optional explainer video.

ahmedkhaleel2004/gitdiagram

Semantic code search and call-graph tracing. An agent skill from yoanbernabeu/grepai.

yoanbernabeu/grepai

Generates, refreshes, validates and uses a compact handbook that maps where a change touches in a repository, using the active Codex session and no external LLM API.

Ruhan-Wang/Harness_Handbook

Write and debug ast-grep rules for structural code search and rewrite.

BiFangKNT/mtga

Searches a codebase by meaning with the jbcontext CLI when you do not know which file or symbol holds the behavior you are looking for.

GitTools/GitVersion

Fills in issue-brief.md and pr-decisions.md for an existing pull request, so you can pick up a PR mid-flight with its linked issue and past review decisions summarized.

pydantic/pydantic-ai-harness

Gives an agent a quick map of a codebase's structure, dependencies, changes and handoffs, and tunes per-project config so the output stays code-first.

JordanCoin/codemap

Semantic code analysis via LSP. An agent skill from lsp-client/lsp-skill.

lsp-client/lsp-skill

Researches code with evidence: traces callers, imports and cross-repo links, diagnoses failures and reports findings with exact file and line references and a confidence label.

bgauryy/octocode

Converts PDFs, text, web pages or a codebase into an Obsidian vault of study notes, practice questions, or a developer onboarding guide.

bevibing/tutor-skills

Create a new release for grepai. An agent skill from yoanbernabeu/grepai.

yoanbernabeu/grepai

Replaces grep, cat, find and ls with the tilth CLI, which returns AST-aware outlines, definitions, usages and callers across many languages in one call.

jahala/tilth

Create architecture diagrams from a local codebase or system description.

Mertcikla/tld

A skill your agent uses when orienting within the Hermes Agent CN Desktop codebase, locating source files, understanding the Tauri+React architecture, finding Rust commands or frontend modules, or…

Eynzof/Hermes-CN-Desktop

Gives an agent working in a Go codebase a structural view through a local MCP server: call graphs, blast-radius and impact analysis, and bounded first-call exploration.

ozgurcd/gograph

Run a multi-agent deep analysis of a codebase, producing AI-readable analysis documents in .ai/docs/ covering structure, dependencies, data flow, request flow, and APIs.

divar-ir/ai-doc-gen

Maps BiSheng's approval-center architecture to exact service files and methods, so a change to approval logic can be located without searching the whole repo.

dataelement/bisheng

Maps the NGINX Kubernetes Ingress Controller codebase: repository layout, architectural layers, layer-crossing rules and which files are generated.

nginx/kubernetes-ingress

Maps a codebase directory by directory and writes linked AGENTS.md files, each pointing to its parent, to document what each area contains.

Yeachan-Heo/oh-my-claudecode

Unified task execution protocol for Codex-only work. An agent skill from lili-luo/aicoding-cookbook.

lili-luo/aicoding-cookbook

Shows everything mem0 has stored for the current project, grouped by category, with a compact search mode and an all-projects view.

mem0ai/mem0

Searches git repositories cloned locally under a sandbox folder to answer questions with cited links and complete code snippets.

stickerdaniel/linkedin-mcp-server

SOP for terminal-based, git-native AI pair programming with Aider (git work-tree + tree-sitter repo-map + edit-format + human-in-loop REPL).

agentsope/SkillAlchemy

This skill should be used when finding, tracing, or understanding code in a repository with SymDex available.

husnainpk/SymDex

Render the shape of code — module boundaries, the types that cross them, signatures, and a cited call graph — for code that already exists or a change about to be built.

citypaul/.dotfiles

Routes code exploration through trace-mcp's indexed dependency graph, using symbol search, outlines, call graphs and change-impact tools instead of Read, Grep and Glob.

nikolai-vysotskyi/trace-mcp

Formalise a product spec for a DynamoDB-Toolbox task — interview, codebase analysis, and Notion write-back.

dynamodb-toolbox/dynamodb-toolbox

Answers call-graph questions that combine several conditions, such as complex functions that reach a target or untested symbols near main, using ripwire's graph-query mode.

redhat-et/ripwire

Analyze a GitHub issue in depth and produce a detailed specification based on codebase analysis.

POW-Software/ByteSync

Filter text, records, code functions, or complete diff hunks by a plain-English description using Jev.

keltokhy/jgrep

Reads a codebase silently, asks only what it cannot infer, and recommends one AI-assisted development methodology stack with a contextual quick start.

FlorianBruniaux/claude-code-ultimate-guide

This skill should be used when the user asks to "connect to Trading 212", "authenticate Trading 212 API", "place a trade", "buy stock", "sell shares", "place market order",, "place pending order"…

trading212-labs/agent-skills