ghost-repo-context — Claude Code skill: repository context

---
name: "ghost-repo-context"
description: "Scans directory structure, detects projects, maps dependencies, and documents code organization into a repo.md file. Use when the user needs a codebase overview, project structure map, or repository context before security analysis."
allowed-tools: Read, Write, Edit, Glob, Grep, Bash
license: apache-2.0
metadata:
  version: 1.1.0
---

# Repository Context Builder

You gather repository context by detecting projects, summarizing their architecture, and writing the results to `repo.md`. Do all work yourself — do not spawn subagents or delegate.

## Inputs

Parse these from `$ARGUMENTS` (key=value pairs):
- **repo_path**: path to the repository root
- **cache_dir**: path to the cache directory (defaults to `~/.ghost/repos/<repo_id>/cache`)

$ARGUMENTS

If `cache_dir` is not provided, compute it:
```bash
repo_name=$(basename "$(pwd)") && remote_url=$(git remote get-url origin 2>/dev/null || pwd) && short_hash=$(printf '%s' "$remote_url" | git hash-object --stdin | cut -c1-8) && repo_id="${repo_name}-${short_hash}" && cache_dir="$HOME/.ghost/repos/${repo_id}/cache" && echo "cache_dir=$cache_dir"
```

## Tool Restrictions

Do NOT use WebFetch or WebSearch. All work must use only local files in the repository.

## Setup

Discover this skill's own directory so you can reference agent files:
```bash
skill_dir=$(find . -path '*/skills/repo-context/SKILL.md' 2>/dev/null | head -1 | xargs dirname)
echo "skill_dir=$skill_dir"
```

---

## Check Cache First

Check if `<cache_dir>/repo.md` already exists. If it does, skip everything and return:

```
Repository context is at: <cache_dir>/repo.md
```

If it does not exist, run `mkdir -p <cache_dir>` and continue.

---

## Workflow

1. **Detect Projects** — Read `<skill_dir>/detector.md` and follow its instructions against `<repo_path>`. Save the full detection output (project details needed for step 2). If detection finds no projects, write a minimal `repo.md` noting "No projects detected" and skip to step 4.

2. **Summarize Each Project** — Read `<skill_dir>/summarizer.md`. For EACH project detected in step 1, follow the summarizer instructions using that project's details (id, type, base_path, languages, frameworks, dependency_files, extensions, evidence). Collect the summary for each project. If summarization fails for a project, note it as "summary unavailable" and continue with remaining projects.

3. **Write repo.md** — Combine detection and summary results into `<cache_dir>/repo.md` using the format in `<skill_dir>/template-repo.md`. For each project include:
   - Detection: ID, Type, Base Path, Languages, Frameworks, Dependency Files, Extensions, Evidence
   - Summary: Architectural summary, Sensitive Data Types, Business Criticality, Component Map, Evidence

4. **Validate** — Read `<cache_dir>/repo.md` back and verify it contains the expected sections from `<skill_dir>/template-repo.md` (e.g., project entries with Detection and Summary fields). If the file is missing or malformed, retry the write once before reporting an error.

5. **Output** — Return: `Repository context is at: <cache_dir>/repo.md`