Polish

Start the dev server, open the feature in a browser, and iterate. You use the feature, say what feels off, and fixes happen.

Phase 0: Get on the right branch

1. If a PR number or branch name was provided, check it out (probe for existing worktrees first).
2. If blank, use the current branch.
3. Verify the current branch is not main/master.

Phase 1: Start the dev server

1.1 Check for .claude/launch.json

Run bash scripts/read-launch-json.sh. If it finds a configuration, use it — the user already told us how to start the project.

1.2 Auto-detect (when no launch.json)

Run bash scripts/detect-project-type.sh to identify the framework.

Route by type to the matching recipe reference for start command and port defaults:

Type	Recipe
rails	references/dev-server-rails.md
next	references/dev-server-next.md
vite	references/dev-server-vite.md
nuxt	references/dev-server-nuxt.md
astro	references/dev-server-astro.md
remix	references/dev-server-remix.md
sveltekit	references/dev-server-sveltekit.md
procfile	references/dev-server-procfile.md
unknown	Ask the user how to start the project

For framework types that need a package manager, run bash scripts/resolve-package-manager.sh and substitute the result into the start command.

Resolve the port with bash scripts/resolve-port.sh --type <type>.

1.3 Start the server

Start the dev server in the background, log output to a temp file. Probe http://localhost:<port> for up to 30 seconds. If it doesn't come up, show the last 20 lines of the log and ask the user what to do.

1.4 Open in browser

Load references/ide-detection.md for the env-var probe table. Open the browser using the IDE's mechanism (Claude Code → open, Cursor → Cursor browser, VS Code → Simple Browser).

Tell the user:

Dev server running on http://localhost:<port>
Browse the feature and tell me what could be better.

Phase 2: Iterate

This is the core loop. The user browses the feature and tells you what to improve. You fix it. Repeat until they're happy.

• When the user describes something to fix → make the change, the dev server hot-reloads
• When the user asks to check something → use agent-browser to screenshot or inspect the page
• When the user says they're done → commit the fixes and stop

No checklist. No envelope. Just conversation.

References

Reference files (loaded on demand):

• references/launch-json-schema.md — launch.json schema + per-framework stubs
• references/ide-detection.md — host IDE detection and browser-handoff
• references/dev-server-detection.md — port resolution documentation
• references/dev-server-rails.md — Rails dev-server defaults
• references/dev-server-next.md — Next.js dev-server defaults
• references/dev-server-vite.md — Vite dev-server defaults
• references/dev-server-nuxt.md — Nuxt dev-server defaults
• references/dev-server-astro.md — Astro dev-server defaults
• references/dev-server-remix.md — Remix dev-server defaults
• references/dev-server-sveltekit.md — SvelteKit dev-server defaults
• references/dev-server-procfile.md — Procfile-based dev-server defaults

Scripts (invoked via bash scripts/<name>):

• scripts/read-launch-json.sh — launch.json reader
• scripts/detect-project-type.sh — project-type classifier
• scripts/resolve-package-manager.sh — lockfile-based package-manager resolver
• scripts/resolve-port.sh — port resolution cascade