r-dev-agent

r-dev-agent

R development agent and language server plugin for Claude Code. Brings first-class R support to Claude Code with smart project detection, strict test discipline, on-demand documentation, and LSP-powered diagnostics.

What's Included

Plugin	Description
r-dev	R development agent — handles packages, Shiny apps, Quarto projects, and general R scripting
r-lsp	R language server — provides diagnostics, go-to-definition, hover docs, and completions

Quick Start

1. Install R prerequisites

install.packages(c("languageserver", "devtools", "testthat", "roxygen2", "pak"))

# For on-demand R documentation in Claude Code:
pak::pak("posit-dev/btw")

2. Add the marketplace

claude plugins marketplace add https://github.com/matheusrech/r-dev-agent.git

3. Install the plugins

claude plugins install r-dev@r-dev-agent
claude plugins install r-lsp@r-dev-agent

4. Set up the btw MCP server (recommended)

claude mcp add -s "user" r-btw -- Rscript -e "btw::btw_mcp_server(tools = 'docs')"

5. Restart Claude Code

The R LSP and agent activate on your next session.

How the Agent Works

Project Detection

When spawned, the agent silently detects your project type and reads the relevant source files:

Marker Files	Project Type	Auto-reads
DESCRIPTION + R/	R package	R/, NAMESPACE, DESCRIPTION
app.R or ui.R + server.R	Shiny app	App files + R/ modules
_quarto.yml or *.qmd	Quarto project	Config + all .qmd files
*.Rmd	R Markdown	All .Rmd files
Fallback	Plain R scripts	All .R files in working dir

Test Safety

The agent follows strict rules to prevent the most common AI coding failure mode — modifying tests to make them pass:

• Can create new test files and add new test cases
• Cannot modify existing assertions, delete tests, add skips, or introduce mocking to bypass failures
• When tests fail, it fixes the implementation — never the tests

Documentation

Uses the btw MCP server on demand — not at startup. The R LSP handles basic signatures and diagnostics passively; btw provides deeper documentation when the agent encounters unfamiliar functions.

Skill Delegation

The agent knows about and invokes these Claude Code skills when they're available:

• r-tidyverse-expert — tidyverse patterns, dplyr 1.1+, rlang, purrr
• testing-r-packages — testthat 3 patterns, snapshots, fixtures
• r-cli — CLI output formatting
• cran-extrachecks — CRAN submission prep
• meta-analysis-workflow — effect sizes, forest plots
• quarto-authoring — Quarto document authoring
• brand-yml — brand styling for Shiny/Quarto
• release-post — release blog posts

Requirements

• R >= 4.1.0 (for native pipe |>)
• Claude Code >= 2.1.0
• R packages: languageserver (for LSP), devtools, testthat
• Recommended: btw (for MCP docs), pak (for dependency management)

Background

This project was inspired by Simon P. Couch's blog posts on using Claude Code for R development. His key insights — that R needs explicit context building, that Claude deletes tests instead of fixing code, and that MCP servers for R documentation are transformative — directly shaped this agent's design.

The gap between R and Python/JavaScript support in Claude Code used to require extensive workarounds. This plugin aims to close that gap.

License

MIT