What is vellum?
vellum is a Claude Code mod by bengous that plan at the frontiers and review the plan in the browser: decisions and interfaces before mechanics, vertical slices each closed by a check. /vellum:start opens a planning mode of its own:. It is listed under Interface and has 5 GitHub stars.
| Type | Claude code mod |
|---|---|
| Author | bengous |
| Repository | bengous/claude-code-plugins |
| Popularity | 5 GitHub stars |
| Category | Interface |
| Security | High risk (44/100) |
| Rank | #684 of 5,272 Claude Code mods; #256 in Interface |
| License | MIT |
| Last commit | 2026-10-17 |
| Hooks | 10 events |
| Sees | every prompt, mcp__vellum__grill_ask|mcp__vellum__propose|AskUserQuestion calls, mcp__vellum__state calls, mcp__vellum__submit calls, the vellum:start skill, the vellum:stop skill |
| Draws on | AbovePrompt |
Is vellum safe to install?
vellum scores 44/100 on the MCPMods security check: High risk. Things to review: sends data over the network; writes files or config; reads environment variables; watches every prompt or event. It passed 2 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 |
|---|---|
| Sends data over the network | Review |
| Starts no processes | Pass |
| Writes files or config | Review |
| Reads environment variables | Review |
| Watches every prompt or event | Review |
| Drives Claude (model calls, prompts) | Note |
| Validator reported problems | Note |
| Has an open-source license | Pass |
API calls in its code
| Call | What it means |
|---|---|
$.agent.list | |
$.agent.spawn | drives Claude |
$.clock.after | |
$.clock.every | |
$.clock.now | |
$.env.get | reads env vars |
$.env.set | sets env vars |
$.fs.stat | reads files |
$.http.fetch | network requests |
$.process.spawn | |
$.prompt.submit | drives Claude |
$.session.cwd | |
$.session.id | |
$.session.root | |
$.store.delete | keeps its own state |
$.store.get | keeps its own state |
$.store.set | keeps its own state |
$.tool.call | drives Claude |
$.tool.register | drives Claude |
$.ui.invalidate | draws interface |
$.ui.log | draws interface |
$.ui.resolve | draws interface |
$.ui.status | draws interface |
How do I install vellum?
- 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/bengous/claude-code-plugins claude plugin validate ./claude-code-plugins/vellum
- Install it. Run this in your terminal, then /reload-plugins in an open session.
git clone https://github.com/bengous/claude-code-plugins && claude --plugin-dir ./claude-code-plugins/vellum
Or ask Claude to set it up
Paste this into Claude Code and it installs vellum for you:
Install the "vellum" Claude Code mod from https://github.com/bengous/claude-code-plugins/tree/main/vellum. Run claude plugin validate on it first and show me what it can access before you enable it.
More from bengous/claude-code-plugins
This repository has 2 Claude Code mods on MCPMods.
- todos: Shows the repository's TODOs in a scrolling band above the prompt, newest first: TODO.md items and TODO/FIXME/HACK code (Review before installing)