Using Context7 for Elm in Claude Code

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How to Invoke It

Since you have Context7 installed, there are a few ways to use it:

1. Inline in any prompt

Just append use context7:

Show me how to define a custom type with variants in Elm. use context7

2. Specify the library directly

If you know the Context7 ID:

How do I use Browser.Navigation in Elm? use library /elm/elm for docs

3. The /docs slash command

If the superpowers plugin installed it:

/docs elm Http module

4. Spawn the docs-researcher agent

For longer lookups that won’t clutter your main context:

spawn docs-researcher to look up Elm's Json.Decode documentation

Under the hood, Context7 exposes two MCP tools: resolve-library-id (maps “elm” to the right Context7 ID) and get-library-docs (fetches the actual content). Claude Code calls these automatically when triggered.

Important Caveat for Elm Specifically

Context7 indexes documentation from official library sources — it’s designed for framework and library docs, not blog posts or tutorials. It works best for libraries with well-structured official documentation (React, Next.js, etc.). Whether Elm’s official guide and package docs are fully indexed is something you’d discover by trying it — if Context7 can’t resolve a library, it tells you. Not every ecosystem is covered.

So when you ask for “blog posts about Elm,” that’s outside Context7’s scope. Context7 fetches official documentation, not community blog content. For blog posts you’d want web search or a different MCP server.

Benefits for an Elm Project

The main value proposition is current, accurate API surfaces injected directly into the prompt context, so that Claude Code generates code against real function signatures rather than hallucinated or outdated ones. For Elm this would mean:

  • Correct type signatures for elm/http, elm/json, elm/browser, etc.
  • Accurate module structure and exposed functions
  • Working code examples from the actual docs rather than from training data (which may conflate Elm 0.18 and 0.19 patterns, for instance)

Given your Elm expertise, the practical benefit is less about teaching you Elm and more about keeping Claude Code honest — ensuring it generates code that actually compiles against the current package APIs rather than inventing function names or mixing up the Platform.Cmd vs Cmd story from different Elm versions.

If Elm Isn’t Indexed

If resolve-library-id comes back empty for Elm, your fallback options are:

  • Web search MCP — Claude Code with superpowers likely has this; it can fetch blog posts and docs from the web directly
  • /add-dir — point Claude Code at a local checkout of the Elm package docs or guide
  • A custom skill — you could create .claude/skills/elm-conventions/SKILL.md with your own Elm patterns, preferred idioms, and references to local doc files, giving Claude Code a reliable Elm knowledge base that you control