Class 9 · 9.4

The FeatureDev plugin & its disciplined process

Meet FeatureDev — Anthropic's own plugin that marches Claude Code through a rigorous, staged feature build. The opposite of Ralph loops: rails, reviews, and repeatable discipline.

🎯 Goal: install discipline⏱ Read: 14 min🧭 Type: concept + setup

We can read tickets and drive GitHub. Now for the piece that makes the whole thing disciplined: a plugin that marches Claude Code through a rigorous, repeatable process for building a feature. It is called FeatureDev, it is an official Anthropic plugin, and it is the exact opposite of the wild Ralph loops from last week.

01Install a plugin the proper way

Back in Claude Code, run /plugin to browse the marketplace. You will spot lots of options — including an official GitHub plugin (a slightly different, environment-variable auth, but it would work much like our MCP setup). That is not the one we want today. We want FeatureDev.

claude

/plugin            # browse the marketplace, arrow to FeatureDev, Enter

02What FeatureDev actually is

FeatureDev guides Claude Code through a disciplined, multi-stage process to build a new feature — complete with specialised agents for exploring the codebase, designing the architecture, and reviewing quality. It keeps the model on rails.

Ralph loops

🌀 Chaos & autonomy

Total freedom: “go for it 10 times, see what happens.” Fast, exploratory, unpredictable.

FeatureDev

🛡️ Rigour & rails

A structured, keep-you-honest process with clear stages and reviews. Predictable and thorough.

If Anthropic uses it, that is a strong signal

FeatureDev is something Anthropic uses internally for their own software development. That is about as good a recommendation as a workflow can get.

03Install at project scope

When you install, Claude Code asks about scope:

User scope

Just for you

The plugin is available in all your projects, but only on your machine.

Project scope ✓

For everyone on the repo

Writes into a .claude folder in the project — commit it and every teammate gets the same plugin. This is what we want.

Choose project scope. Claude Code creates a .claude folder — a real file we can commit, so the whole team shares this disciplined setup.

04The disciplined process, stage by stage

Instead of leaping straight to code, FeatureDev walks a sequence. Knowing the shape helps you stay the boss and spot when a stage gets skipped (it happens — more on that soon).

A representative view of the on-rails flow: explore → clarify → architect → plan → implement → review → finalize.

Stages can get skipped — stay watchful

Even a disciplined plugin is not perfectly reliable. Later today Claude quietly skips the quality-review stage and only owns up when we ask it directly. The lesson: know the stages, and check that each one actually happened. You are still the boss.

05Housekeeping: .gitignore and commit the setup

Two quick, valuable chores — and we let Claude do them. First, a good .gitignore so we never commit secrets or junk. One prompt covers it:

“Please create a boilerplate .gitignore for this new project for a typical Python FastAPI / Next.js web app, then commit and push to GitHub.”

Claude writes a sensible .gitignore (crucially including .env so API keys never leak), then commits, pushes, and even pulls to sync the earlier merge. Check GitHub — the new .gitignore is there. Second, remember the .claude folder from installing FeatureDev at project scope: commit that too, so every teammate inherits the same plugin.

Why committing .claude matters

This is the quiet superpower of project scope: your plugins, and later your skills and project CLAUDE.md, all live in the repo. Clone the repo and you clone the whole working setup — everyone codes with the same rails.

✓ Key takeaways

Browse and install plugins with /plugin; we install FeatureDev, Anthropic's official feature-building plugin.
FeatureDev is the opposite of Ralph loops — a disciplined, on-rails, multi-stage process with specialised agents.
Install at project scope so the .claude folder can be committed and shared with the team.
The stages run roughly: explore → clarify → architect → plan → implement → review → finalize — and a stage can get skipped, so verify.
Let Claude create a .gitignore (include .env!) and commit .claude so the setup travels with the repo.