building-github-index

building-github-index is a skill for Claude Code, Codex from oaustegard/claude-skills. It costs 66 tokens per session (958 once invoked), scanned A, original, MIT.

A command-line tool that creates searchable Markdown indexes for GitHub repositories, which are online project folders for code and documentation. It can describe documentation files or list functions and classes in code.

In plain words
What is it for?
Use it to prepare GitHub documentation, technical blogs, knowledge bases, or code repositories as reference material for Claude projects.
Why use it?
It helps you find relevant information in large or multiple repositories without reading every file. You can also limit the index to selected files or skip downloading file contents.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to prepare GitHub documentation, technical blogs, knowledge bases, or code repositories as reference material for Claude projects.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/oaustegard/claude-skills/building-github-index
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.

Any agent
npx skills add oaustegard/claude-skills --skill building-github-index
Clone the repo
git clone --depth 1 https://github.com/oaustegard/claude-skills

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 building-github-index

README.md
[![agentmods](https://agentmods.dev/badge/skills/oaustegard/claude-skills/building-github-index/github.svg)](https://agentmods.dev/skills/oaustegard/claude-skills/building-github-index)
Your own site
<a href="https://agentmods.dev/skills/oaustegard/claude-skills/building-github-index"><img src="https://agentmods.dev/badge/skills/oaustegard/claude-skills/building-github-index/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.

agentmods 80×15 button for building-github-index

Your own site · 80×15
<a href="https://agentmods.dev/skills/oaustegard/claude-skills/building-github-index"><img src="https://agentmods.dev/badge/skills/oaustegard/claude-skills/building-github-index.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 958 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 2 findings, up to medium

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 →

  • medium Data Exfiltration · line 88
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
  • medium Data Exfiltration · line 93
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
How audits are shown
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 5.1 $0.00066 $0.00958
Opus 5 $0.00033 $0.00479
Sonnet 5 $0.00013 $0.00192
Haiku 4.5 $0.00007 $0.00096

Measured 9d ago against content hash f01983c2948b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

building-github-index scanned grade A with 1 finding 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 9d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/github_index.py, scripts/pk_index.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

{API curl commands}
building-github-index/SKILL.md · 122 lines

How it starts

The opening of the file, as written. The whole thing — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Building GitHub Index

Create markdown indexes of GitHub repositories optimized for Claude project knowledge. Indexes enable retrieval via GitHub API with semantic descriptions for effective matching.

Quick Start

# Documentation repos (markdown/notebooks)
python scripts/github_index.py owner/repo -o index.md

# Code repos (extract symbols via tree-sitter)
python scripts/github_index.py owner/repo --code-symbols -o index.md

# Multiple repos combined
python scripts/github_index.py owner/repo1 owner/repo2 -o combined.md

Script Options

Flag Description
-o, --output Output file (default: github_index.md)
--token GitHub PAT; also reads GITHUB_TOKEN env
--include-patterns Only index matching globs: "docs/**" "src/**"
--exclude-patterns Skip matching globs: "test/**"
--max-files Cap files per repo (default: 200)
--skip-fetch Tree only, no content fetch (fast, filename-only descriptions)
--code-symbols Include code files, extract function/class names via tree-sitter

Description Extraction Priority

  1. YAML frontmatter - title: and description: fields
  2. Markdown headings - First h1/h2 as title, subsequent as topics
  3. Notebook cells - First markdown cell heading
  4. Code symbols - Public function/class names (with --code-symbols)
  5. Path-derived - Convert filename to words (fallback)

When Descriptions Fail

Some repos have stub files (links to external docs, empty readmes). In these cases:

Manual curation recommended. Use the tree output and domain knowledge:

# Get tree structure only (fast)
python scripts/github_index.py owner/repo --skip-fetch -o skeleton.md
# Then manually enhance descriptions based on domain knowledge

For code-heavy repos with embedded apps:

  • Directory names encode purpose: acc_wav_gen → "ACC waveform generation"
  • Peripheral acronyms map to functions: AFEC=ADC, MCAN=CAN, TWIHS=I2C
  • Operation modes: blocking, interrupt, dma, polled

Read the full file on GitHub · 122 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 9d ago First seen · 122 lines · 66 tokens per session scan A f01983c2948b

Subscribe to this mod's changes

building-github-index is a skill published in the GitHub repository oaustegard/claude-skills (147 stars, last pushed today), licensed MIT. It adds 66 tokens to every session and 958 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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