claude-grammar

claude-grammar

Background English grammar coach for Claude Code, packaged as a native plugin. Runs on every prompt you submit, finds up to 3 grammar issues (ordered A1 → C1+ by CEFR level), and shows them in your statusline — never in Claude's context.

Claude Code-native: a single UserPromptSubmit hook, plain bash, no third-party services. The bundled /claude-grammar:setup command wires it into your statusline (ccstatusline, native statusLine, or a custom script).

What it looks like

Type a message with errors, hit enter — your prompt submits immediately. ~1–2 seconds later, the corrections appear in your statusline as a tree:

EN(2)
├ i has → I have
└ he go → he goes

Originals are colored red, fixes green; the badge and tree glyphs are dim. Suggestions go from lower to higher CEFR level (A1 → C1+). When your message is fine, the statusline stays clean.

Corrections are written for you, not for Claude. They live in a per-session file under /tmp/, never enter the model's context window, and won't influence its next response.

Install

claude plugin marketplace add rapita/claude-grammar
claude plugin install claude-grammar@rapita-claude-grammar

Then run the setup command in Claude Code:

/claude-grammar:setup

It copies the statusline widget into ~/.claude/grammar-status.sh and wires it into whatever statusline you already use. Re-run any time — it's idempotent and creates timestamped backups before any write.

Restart Claude Code, and the next message you submit will be checked.

Prerequisites

• macOS or Linux
• Claude Code installed and authenticated
• jq (brew install jq / apt install jq)
• A statusline tool — the setup command can wire ccstatusline or Claude Code's native statusLine for you

Cost

A claude -p call with Haiku fires on every prompt that passes the gates (non-empty, doesn't start with /, ≥10 chars). A few hundred input tokens and ~50 output tokens per check — negligible on the Pro/Team plans.

Troubleshooting

• Nothing shows in the statusline → run /claude-grammar:setup again. It'll detect what's missing and either fix it or print exact instructions. If it reports everything is wired, restart Claude Code.
• Not logged in · Please run /login → the hook uses the same auth as your shell claude. If something is stripping Claude's environment, restore it.
• Want to silence it temporarily → claude plugin disable claude-grammar@rapita-claude-grammar (re-enable with enable).

License

MIT. See CONTRIBUTING.md for design rationale, source install, tests, and everything else you'd touch when hacking on the plugin.