Write CLAUDE.md

[larnsce]

Goal

One short CLAUDE.md in this repository so every Claude Code session reads the same conventions. No recorded skill list, no hooks, no settings allowlist. Posit's r-lib skills can be installed at user level; that is a personal choice, not repository content.

Rewritten 2026-09-04 per dev/decisions-2026-09.md. The washr half of the earlier text belongs in washr if wanted.

Contents

• Purpose in two sentences: index metapackage, harvested catalog shipped as internal data, engine only
• Layout from Scaffold the owdata package with washr 1.1.0 #1, with the generated files that are never hand-edited: R/sysdata.rda, inst/extdata/, man/, NAMESPACE, data-raw/packages.json, data-raw/harvest_report.md
• Commands: Rscript -e "devtools::document()", devtools::test(), devtools::check(), Rscript data-raw/harvest.R with the local backend and a UTF-8 locale; the GitHub backend is never run from tests
• Branch rule: branches and pull requests to main; the harvest bot opens a PR; never commit generated data by hand
• Dependency rule: code under R/ uses base R and the packages already in Imports; do not add tidyverse packages to Imports; dplyr, purrr, stringr and readr are fine in data-raw/ and tests
• Test bar: a behavioural test per export, every expect_error() names its message, fixtures under tests/testthat/fixtures/ read with test_path(), the schema and value gates in test-schema.R gate the harvest
• Style: no em dashes, no emojis, blank line after headings, en-GB
• Pointers: Tracking: build the owdata index metapackage #12 and the decisions file

Acceptance criteria

• The file exists on main and fits on one screen
• A session asked to add a helper under R/ does not add a tidyverse package to Imports