DocMeta

Know what breaks before you break it.

DocMeta answers the questions you ask before touching unfamiliar code:

| Question | Command | |----------|---------| | "What does this file do?" | docmeta lookup src/auth.ts | | "What breaks if I change this?" | docmeta graph --blast-radius src/auth.ts | | "Is this code dead?" | docmeta graph --orphans | | "Are there circular dependencies?" | docmeta graph --cycles | | "Where does execution start?" | docmeta graph --entry-points |

No API keys. No external services. Just JSON files that track what code does and what depends on what.

The Problem

AI coding agents read your files to understand them. For large codebases, this means:

• Reading hundreds of lines to find what a file does
• Missing dependencies and breaking things downstream
• No way to know if code is even used anymore
• Circular dependencies hiding in plain sight

The Solution

A .docmeta.json file in each folder with:

• Purpose — What this code does (skip reading the whole file)
• usedBy — What breaks if you change this (blast radius)
• uses — What this code depends on

Plus a docmeta graph command that builds the full dependency picture:

$ docmeta graph

DocMeta Graph Analysis

Entry Points (4):
  /bin/cli.js
  /bin/mcp-server.js
  /bin/setup.js
  /app/page.tsx

Orphans (2 files with no dependents - dead code candidates):
  /lib/deprecated/old-auth.ts
  /utils/unused-helper.js

Cycles (1 circular dependency):
  /lib/a.ts -> /lib/b.ts -> /lib/c.ts -> /lib/a.ts

Summary: 47 files, 4 entry points, 2 orphans, 1 cycle

Quick Start

npx @brbcoffeedebuff/docmeta setup

The setup wizard:

1. Adds MCP tools to Claude Code
2. Creates .docmeta.json scaffolds
3. Builds the dependency graph
4. Installs the auto-sync agent

Or manually:

npx @brbcoffeedebuff/docmeta init      # Create scaffolds
npx @brbcoffeedebuff/docmeta usedby    # Build dependency graph
npx @brbcoffeedebuff/docmeta graph     # Analyze the graph

CLI Commands

Graph Analysis (the good stuff)

docmeta graph                          # Full analysis: entry points, orphans, cycles
docmeta graph --blast-radius src/api   # What breaks if I change this? (transitive)
docmeta graph --orphans                # Dead code candidates
docmeta graph --cycles                 # Circular dependencies
docmeta graph --entry-points           # Where execution starts
docmeta graph --output graph.json      # Export for tooling

Documentation Management

docmeta init [path]                    # Create .docmeta.json scaffolds
docmeta usedby [path]                  # Populate usedBy fields (imports)
docmeta calls [path]                   # Populate calls/calledBy fields (HTTP APIs)
docmeta update <file> --purpose "..."  # Set a file's purpose
docmeta update <file> --history "..."  # Add a history entry
docmeta update --sync                  # Sync with filesystem
docmeta crawl                          # Fill in [purpose] placeholders
docmeta check                          # Find stale/incomplete docs

HTTP API Dependencies (Next.js, etc.)

For frameworks like Next.js where components call API routes via fetch/axios:

docmeta calls                          # Scan for fetch/axios calls to /api/*

This creates bidirectional links:

• calls — API routes this file calls (e.g., ["/app/api/users/route.ts"])
• calledBy — Files that call this route via HTTP

The graph analysis uses both import dependencies (usedBy) and HTTP dependencies (calledBy) to find dead code and calculate blast radius.

MCP Server

docmeta mcp                            # Start MCP server for Claude Code

The Schema

{
  "v": 3,
  "purpose": "User authentication and session management",
  "files": {
    "auth.ts": {
      "purpose": "JWT token generation, validation, and refresh logic",
      "exports": ["createToken", "validateToken", "refreshToken"],
      "uses": ["./config", "@/lib/crypto"],
      "usedBy": ["/app/api/login/route.ts", "/middleware.ts"],
      "calls": ["/app/api/session/route.ts"],
      "calledBy": []
    }
  },
  "history": [
    ["2025-01-10T14:30:00Z", "Added refresh token support", ["auth.ts"]]
  ],
  "updated": "2025-01-10T14:30:00Z"
}

Dependency fields:

• uses / usedBy — Import dependencies (what this file imports / what imports this)
• calls / calledBy — HTTP dependencies (API routes called via fetch/axios)

The Key Field: usedBy

When you see:

"usedBy": ["/app/api/login/route.ts", "/middleware.ts"]

You know exactly what breaks if you change this file. The docmeta graph --blast-radius command follows these chains transitively to show the full impact.

Language Support

DocMeta is optimized for TypeScript/JavaScript with full feature support. Other languages have basic support with scaffolding.

Feature Support by Language

| Feature | TypeScript/JS | Python | Go | Rust | Others | |---------|:-------------:|:------:|:--:|:----:|:------:| | Export detection | ✅ Full | ✅ Basic | ✅ Basic | ✅ Basic | ❌ Manual | | Import detection | ✅ Full | ⚠️ Relative only | ⚠️ Internal only | ✅ Basic | ❌ Manual | | HTTP calls (calls/calledBy) | ✅ Full | ❌ | ❌ | ❌ | ❌ | | Path aliases (tsconfig.json) | ✅ | ❌ | ❌ | ❌ | ❌ | | usedBy resolution | ✅ | ✅ | ✅ | ✅ | ❌ Manual |

TypeScript/JavaScript (Full Support)

• Exports: Named exports, default exports, re-exports, type exports
• Imports: ES modules, CommonJS require, dynamic imports
• HTTP calls: fetch, axios, useSWR, useQuery patterns
• Path aliases: Reads from tsconfig.json/jsconfig.json (defaults: @/, ~/)

Python (Basic Support)

• Exports: __all__ declarations, public functions/classes (no underscore prefix)
• Imports: Relative imports only (e.g., from .module import)
• Limitations: Absolute imports not tracked, HTTP calls not detected

Go (Basic Support)

• Exports: Public identifiers (capitalized names)
• Imports: Internal package imports (not standard library)
• Limitations: Module path detection is simplified, HTTP calls not detected

Rust (Basic Support)

• Exports: pub items (functions, structs, enums, traits, modules)
• Imports: crate::, super::, self:: paths, mod declarations
• Limitations: External crate usage not tracked, HTTP calls not detected

Other Languages

Scaffolds are created with empty exports and uses arrays. Fill these in manually or let Claude Code populate them as it works with your code.

TypeScript Path Aliases

DocMeta automatically reads path aliases from tsconfig.json or jsconfig.json:

// tsconfig.json
{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@/*": ["./*"],
      "@components/*": ["./src/components/*"],
      "@utils/*": ["./src/utils/*"]
    }
  }
}

Default aliases (always available, even without tsconfig):

• @/ → project root (e.g., @/lib/auth → /lib/auth.ts)
• ~/ → project root (e.g., ~/utils → /utils/index.ts)

Custom aliases are loaded from your tsconfig.json/jsconfig.json compilerOptions.paths configuration. The CLI will report loaded aliases:

📦 Loaded 5 path aliases from tsconfig.json/jsconfig.json
   Custom: @components/*, @utils/*, @hooks/*

MCP Integration

Claude Code gets these tools automatically after setup:

| Tool | What it does | |------|--------------| | docmeta_lookup | Get metadata for a file or folder | | docmeta_blast_radius | Find all files affected by a change | | docmeta_graph | Analyze cycles, orphans, entry points | | docmeta_search | Find files by purpose |

Add manually if needed (~/.claude/settings.json):

{
  "mcpServers": {
    "docmeta": {
      "command": "npx",
      "args": ["@brbcoffeedebuff/docmeta", "mcp"]
    }
  }
}

Auto-Sync Agent

The setup wizard installs a subagent that automatically updates documentation after code changes:

• Syncs new/deleted files
• Fills in missing purposes
• Rebuilds dependency graph
• Reports issues

Configuration

Create .docmetarc.json in your project root:

{
  "maxHistoryEntries": 15,
  "customIgnoreDirs": ["generated", "vendor"],
  "customIgnoreFiles": ["*.generated.ts"],
  "customEntryPointPatterns": [
    "app/**/page.tsx",
    "app/**/route.ts",
    "app/**/layout.tsx"
  ]
}

Entry Point Patterns

Entry points are files that don't need to be imported (frameworks call them directly). Configure patterns to prevent false positives in dead code detection:

{
  "customEntryPointPatterns": [
    "app/**/page.tsx",
    "app/**/route.ts",
    "app/**/layout.tsx",
    "scripts/**/*.ts",
    "bin/**/*.js"
  ]
}

Patterns support:

• ** — matches zero or more directories
• * — matches any filename characters

FAQ

Why not just let the AI read the code?

It does. But checking a 3-sentence purpose is faster than reading 300 lines. And usedBy gives dependency info that isn't obvious from reading one file.

Why not use embeddings?

Embeddings are opaque and probabilistic. DocMeta is visible, deterministic, and version-controlled. You can read it, edit it, and trust it.

Should I commit .docmeta.json?

Yes. Review it in PRs like code.

What about stale docs?

The auto-sync agent handles this. Run docmeta check to verify.

See Also

• SCHEMA.md — Complete field reference
• CRUD.md — Lifecycle workflows

License

Apache 2.0