What is hal-grammar-check?
hal-grammar-check is a Claude Code mod by vinta that grammar-check your prompt as you type, shown above the prompt box. It is listed under Interface and has 139 GitHub stars.
| Type | Claude code mod |
|---|---|
| Author | vinta |
| Repository | vinta/hal-9000 |
| Popularity | 139 GitHub stars |
| Category | Interface |
| Security | Low risk (84/100) |
| Rank | #104 of 5,272 Claude Code mods; #25 in Interface |
| License | MIT |
| Last commit | 2026-10-17 |
| Stars this week | +1 |
| Hooks | 4 events |
| Sees | every prompt |
| Draws on | AbovePrompt |
Is hal-grammar-check safe to install?
hal-grammar-check scores 84/100 on the MCPMods security check: Low risk. Things to review: watches every prompt or event. It passed 6 of 8 checks.
Mod footprints come from claude plugin validate, which lists every event a mod hooks and every API call it makes without running it.
| Check | Result |
|---|---|
| No network access | Pass |
| Starts no processes | Pass |
| Writes no files or config | Pass |
| Doesn't read environment variables | Pass |
| Watches every prompt or event | Review |
| Drives Claude (model calls, prompts) | Note |
| Passes claude plugin validate | Pass |
| Has an open-source license | Pass |
API calls in its code
| Call | What it means |
|---|---|
$.clock.after | |
$.model.complete | drives Claude |
$.process.spawn | |
$.state.get | |
$.state.set | |
$.ui.resolve | draws interface |
How do I install hal-grammar-check?
- Check your Claude Code version. Mods need Claude Code 2.1.287 or later and are on by default.
claude --version
- Read its footprint. This lists every event it hooks and every API call it makes, without running it.
git clone https://github.com/vinta/hal-9000 claude plugin validate ./hal-9000/plugins/hal-grammar-check
- Install it. Run this in your terminal, then /reload-plugins in an open session.
claude plugin marketplace add vinta/hal-9000 && claude plugin install hal-grammar-check@hal-9000
Or ask Claude to set it up
Paste this into Claude Code and it installs hal-grammar-check for you:
Install the "hal-grammar-check" Claude Code mod from https://github.com/vinta/hal-9000/tree/main/plugins/hal-grammar-check. Run claude plugin validate on it first and show me what it can access before you enable it.
More from vinta/hal-9000
This repository has 2 Claude Code mods on MCPMods.
- hal-session-auto-rename: Automatically name each session and rename it as the conversation evolves (Low risk)