# How to Add Custom Documentation Sources to Context Hub: A Complete Guide
> Learn to add custom documentation sources to Context Hub by configuring local directories or remote CDN URLs in your config.yaml. Enhance your knowledge base effortlessly.
- Repository: [Andrew Ng/context-hub](https://github.com/andrewyng/context-hub)
- Tags: how-to-guide
- Published: 2026-03-20
---
**Add custom documentation sources to Context Hub by defining them in `~/.chub/config.yaml` and pointing to either a local directory containing a built registry or a remote CDN URL.**
Context Hub is an open-source knowledge management system developed by Andrew Ng's team (andrewyng/context-hub) that aggregates documentation and skills from multiple sources. While it ships with public registries, organizations often need to add custom documentation sources to Context Hub to incorporate private APIs, internal wikis, or proprietary knowledge bases.
## Understanding the Source Configuration System
Context Hub loads its knowledge base from **one or more "sources"** defined in the user-level configuration file. The system distinguishes between remote sources (CDN URLs) and local sources (filesystem paths).
In [`cli/src/lib/config.js`](https://github.com/andrewyng/context-hub/blob/main/cli/src/lib/config.js), the `loadConfig()` function (lines 25-48) reads `~/.chub/config.yaml` and constructs the `config.sources` array. Each source object must include:
- **`name`**: A unique identifier for the source
- **`url`**: For remote CDN-hosted registries
- **`path`**: For local directory-based registries
## Building a Custom Documentation Registry
Before you can add custom documentation sources to Context Hub, you must build a valid registry from your content files.
### Step 1: Prepare Your Content Structure
Organize your Markdown files with front-matter in a directory tree. Each documentation entry should include a [`DOC.md`](https://github.com/andrewyng/context-hub/blob/main/DOC.md) file with metadata:
```yaml
---
id: mycompany/internal-api
title: Internal API Reference
description: Authentication and endpoints for internal services
---
```
### Step 2: Generate the Registry
Use the CLI build command to compile your content into a Context Hub-compatible registry:
```bash
chub build my-content/ -o .chub-local/
```
This command, implemented in [`cli/src/commands/build.js`](https://github.com/andrewyng/context-hub/blob/main/cli/src/commands/build.js), generates three critical files in the output directory:
- **[`registry.json`](https://github.com/andrewyng/context-hub/blob/main/registry.json)**: The main registry containing all entries and metadata
- **[`search-index.json`](https://github.com/andrewyng/context-hub/blob/main/search-index.json)**: Optimized search index for fast queries
- **[`meta.json`](https://github.com/andrewyng/context-hub/blob/main/meta.json)**: Version and configuration metadata
## Configuring Multiple Sources in Context Hub
Once you have built your local registry, you must register it in the Context Hub configuration to add custom documentation sources alongside public ones.
### Editing the Configuration File
Modify `~/.chub/config.yaml` to include your custom source:
```yaml
sources:
- name: community
url: https://cdn.aichub.org/v1
- name: internal
path: /home/you/.chub-local
source: community,internal
```
The `source:` field controls which sources are trusted for lookups. When you add custom documentation sources to Context Hub, including them in this list ensures they are available for search and retrieval operations.
## How Context Hub Merges Multiple Sources
In [`cli/src/lib/registry.js`](https://github.com/andrewyng/context-hub/blob/main/cli/src/lib/registry.js), the `getMerged()` function (lines 97-112) handles the aggregation of all configured sources:
1. **Iterates** over `config.sources`
2. **Calls** `loadSourceRegistry(source)` for each entry to read its [`registry.json`](https://github.com/andrewyng/context-hub/blob/main/registry.json)
3. **Tags** every document with `_source` (the source name) and `_sourceObj` (the full source configuration)
4. **Caches** the merged result in `_merged` for subsequent lookups
The `isMultiSource()` helper (lines 107-110) returns `true` when `config.sources.length > 1`, enabling the CLI to display source labels for entries with colliding IDs (e.g., `internal:openai/chat`).
## Accessing Custom Documentation
After you add custom documentation sources to Context Hub, you can query them using standard CLI commands:
### Search Across All Sources
```bash
chub search "authentication"
```
This searches both the public CDN and your internal registry simultaneously.
### Retrieve Specific Entries
```bash
chub get internal:mycompany/internal-api
```
If the ID is unique across all sources, you can omit the source prefix:
```bash
chub get mycompany/internal-api
```
## Summary
- **Configuration**: Define custom sources in `~/.chub/config.yaml` with `name` and either `url` (remote) or `path` (local) attributes.
- **Building**: Use `chub build -o