hexdocs-fetcher

HexDocs Fetcher

Efficiently fetch Elixir library documentation from hexdocs.pm using Claude Code's native WebFetch tool.

Usage

When researching libraries, use WebFetch:

# Fetch library overview
WebFetch(
  url: "https://hexdocs.pm/oban",
  prompt: "Extract the main documentation, including module overview, installation instructions, and key functions. Format as clean markdown."
)

Fetch specific module docs

WebFetch( url: "https://hexdocs.pm/phoenix_live_view/Phoenix.LiveView.html", prompt: "Extract the module documentation including all public functions, their specs, and examples." )

Fetch getting started guide

WebFetch( url: "https://hexdocs.pm/ecto/getting-started.html", prompt: "Extract the complete getting started guide content." )


## Token Efficiency

WebFetch automatically converts HTML to markdown and extracts relevant content:

| Source | Raw HTML | With WebFetch | Benefit |
|--------|----------|---------------|---------|
| HexDocs page | ~80k tokens | ~15k tokens | **80% reduction** |
| Phoenix docs | ~120k tokens | ~25k tokens | **79% reduction** |
| README | ~20k tokens | ~8k tokens | **60% reduction** |

## Integration with hex-library-researcher

When evaluating libraries, fetch docs efficiently:

Get library overview with focused extraction

WebFetch( url: "https://hexdocs.pm/oban", prompt: "Extract: 1) Installation instructions 2) Main features 3) Basic usage example" )


## Common HexDocs URLs

Library overview

https://hexdocs.pm/{library}

Module documentation

https://hexdocs.pm/{library}/{Module}.html https://hexdocs.pm/{library}/{Module.Submodule}.html

Guides

https://hexdocs.pm/{library}/guides.html https://hexdocs.pm/{library}/{guide-name}.html

API reference

https://hexdocs.pm/{library}/api-reference.html


## Prompt Strategies

Use focused prompts for better extraction:

For API docs

prompt: "Extract all public function docs with @spec and examples"

For guides

prompt: "Extract the complete guide content preserving code examples"

For troubleshooting

prompt: "Extract any troubleshooting sections, common errors, and FAQs"

For configuration

prompt: "Extract configuration options and their defaults"


## Caching

WebFetch includes automatic 15-minute caching. When fetching the same URL multiple times in a session, results are cached automatically.

For longer persistence, save to planning directory:

After fetching, write the result to a file

Write( file_path: ".claude/plans/{slug}/research/docs/oban.md", content: "{extracted content}" )


## Tidewave Alternative

If Tidewave MCP is available, prefer `mcp__tidewave__get_docs` for exact version-matched documentation:

mcp__tidewave__get_docs(module: "Oban.Worker")


This fetches docs for the exact version in your `mix.lock`.

## Iron Laws

1. **NEVER fetch entire HexDocs sites** — always target specific modules or guides
2. **Use focused prompts** — generic fetches waste tokens; specify what to extract
3. **Prefer Tidewave when available** — exact version match beats generic hexdocs.pm

About this skill

Usage