cc-grammar

Automatic grammar checking for coding agents. Catches grammar, spelling, and punctuation errors in your messages and displays them in the status line — without polluting the conversation context.

Supports Claude Code, Pi Coding Agent, Codex CLI, and Gemini CLI.

Uses claude -p (Claude Code pipe mode) — no API keys needed. Piggybacks on your existing Claude Code authentication.

How it works

1. You type a message and hit enter
2. Your message is sent to a fast LLM for grammar analysis (in the background)
3. Errors (if any) are displayed in the status line at the bottom of your terminal
4. The agent's conversation stays clean — no context injection

Prerequisites

• Node.js >= 20
• Claude Code installed and authenticated
• One of: Claude Code, Pi, Codex CLI, or Gemini CLI

Installation

Claude Code (default)

npx cc-grammar install

Pi Coding Agent

pi install npm:cc-grammar

Codex CLI

npx cc-grammar install --agent codex

Gemini CLI

npx cc-grammar install --agent gemini

Configure model (optional)

Default model is haiku (fast and cheap). To change:

npx cc-grammar set model sonnet

Verify it works:

npx cc-grammar test

Uninstall

npx cc-grammar uninstall                    # Claude Code (default)
npx cc-grammar uninstall --agent codex      # Codex CLI
npx cc-grammar uninstall --agent gemini     # Gemini CLI
pi remove npm:cc-grammar                    # Pi

Update

npx cc-grammar update

Commands

| Command | Description | |---------|-------------| | npx cc-grammar install [--agent <name>] | Install for a coding agent | | npx cc-grammar uninstall [--agent <name>] | Remove from a coding agent | | npx cc-grammar update | Update to latest version | | npx cc-grammar setup | Interactive model setup | | npx cc-grammar set <field> <val> | Update a single setting | | npx cc-grammar config | Show current config | | npx cc-grammar test | Test grammar check with sample input | | npx cc-grammar models | List available model aliases |

Supported agents: claude (default), pi, codex, gemini

Settings fields: model, minLength, systemPrompt

Model aliases

| Alias | Description | |-------|-------------| | haiku | Default — fast and cheap | | sonnet | Balanced | | opus | Most capable |

Or use a full model ID (e.g. claude-haiku-4-5-20251001).

Usage

Just type normally in your coding agent. Grammar errors appear automatically in the status line:

✏️  "I has" → "I have" (subject-verb) | "thinked" → "thought" (irregular past)

Messages shorter than 10 characters and slash commands are skipped.

Architecture

lib/grammar-engine.mjs          ← Agent-agnostic core (uses claude -p)
  ├── adapters/claude-code/     ← Shell hook + status line
  ├── adapters/pi/              ← TypeScript extension (in-process)
  ├── adapters/codex/           ← Shell hook
  └── adapters/gemini/          ← Shell hook

All adapters share the same grammar engine and config (~/.config/claude-grammar/grammar.config.json).

License

MIT