julia-lsp — Claude Code plugin for Julia: what it does, how to install
Wires the Julia language server into Claude, so the agent gets diagnostics, go-to-definition and reference search for Julia projects.
/plugin marketplace add anthropics/claude-plugins-community
/plugin install julia-lsp@claude-communityWhat julia-lsp does
This plugin connects Claude to LanguageServer.jl. The agent stops guessing about your Julia code and starts asking the server: where is this defined, who calls it, what does the type look like.
You need LanguageServer.jl in your Julia environment first. Add it with using Pkg; Pkg.add("LanguageServer"), and the author suggests a global environment such as @v1.12. Skip that step and there is no server for the plugin to talk to.
Expect the first request of a session to hang for 30–60 seconds while Julia JIT-compiles the server. After that it responds quickly. startupTimeout in .claude-plugin/plugin.json is set to 120 seconds to cover that compile, and you can raise or lower it. To try the plugin straight from a checkout, run claude --plugin-dir /path/to/this/repo.
What it helps with
- jump to the definition of a function buried in another Julia module
- list every call site of a method
- see diagnostics while editing instead of after a test run
- check a signature or type by hovering
- navigate an unfamiliar Julia package without grepping
Example prompts for the agent
- Find every reference to
solve_stepin this project - Go to the definition of
AbstractModeland show me its fields - What diagnostics does LanguageServer report for
src/solver.jl?
How to install julia-lsp
Plugin marketplace
/plugin marketplace add anthropics/claude-plugins-community/plugin install julia-lsp@claude-communityStep by step, with commands for each platform: Claude Code plugins: marketplaces, installing, and building your own
Questions about julia-lsp
How do I install julia-lsp in Claude Code?
Add the marketplace first: /plugin marketplace add anthropics/claude-plugins-community, then install the plugin: /plugin install julia-lsp@claude-community.
What does julia-lsp do?
It gives Claude language-server features for Julia through LanguageServer.jl: diagnostics, go-to-definition, find references and hover information.
Why is the first request so slow?
Julia JIT-compiles LanguageServer.jl on first use, which takes 30–60 seconds. Later requests are fast, and startupTimeout is set to 120 seconds in the plugin config.
Source text
SKILL.md · MIT
# julia-lsp
Julia language server plugin for [Claude Code](https://claude.ai/code), powered by [LanguageServer.jl](https://github.com/julia-vscode/LanguageServer.jl).
Gives Claude Code real-time code intelligence for Julia projects: diagnostics, go-to-definition, find references, hover info, and more.
## Prerequisites
Install [LanguageServer.jl](https://github.com/julia-vscode/LanguageServer.jl) in your Julia environment. It's recommended to install this in your global Julia environment (e.g. `@v1.12`).
```julia
using Pkg; Pkg.add("LanguageServer")
```
## Usage
```bash
claude --plugin-dir /path/to/this/repo
```
The first LSP request in a session may take 30-60 seconds while Julia JIT-compiles LanguageServer.jl. Subsequent requests are fast.
## Configuration
The plugin is configured in `.claude-plugin/plugin.json`. The `startupTimeout` is set to 120 seconds to accommodate Julia's JIT compilation. You can adjust this if needed.
## License
MIT
© alecloudenback · MIT · alecloudenback/ClaudeCodeJuliaLSP
