Editors

One generator

poetry:editor writes an MCP config for each editor, a snippet file generated from the component registry, and a check hook that lints every template an agent edits. The config writes are upserts: a file keeps its other servers and hooks, one that already has Poetry is left alone, and a JSONC file Poetry cannot parse is reported, never clobbered.

The MCP server

Poetry's agent surface is a standard stdio MCP server (bundle exec poetry-agent, from the poetry-agent gem): boot-free, read-only, no SDK. Its ten tools teach an agent the catalog and gate its work. Call compose first, build from primitives, run check last, and take a PASS verdict rather than an eyeball.

RubyMine 2025.2+ is already an MCP client: Settings, then Tools, AI Assistant, Model Context Protocol; add a stdio server running bundle exec poetry-agent or import the .mcp.json.

The check hook

A rule in a skill file competes with everything else the agent is holding; a hook does not. poetry:editor writes bin/poetry-check-hook and registers it so that every template an agent edits under app/ is linted the moment the edit lands: Claude Code's PostToolUse hook on Edit and Write, Cursor's postToolUse on Write. Errors go straight back to the agent as feedback it has to act on, warnings arrive as context, and a clean template costs one Rails boot and says nothing. The script is plain Ruby with no dependencies and runs bin/rails poetry:check on the one file, so it sees exactly what the rake task sees. Anything that is not an app template is ignored without booting Rails, and a check that cannot run at all fails open.

Claude Code reads hooks at session start: after generating, start a new session (or check /hooks) before expecting feedback. The Cursor entry is best-effort; its edit payload is read leniently and the hook stays silent when it finds no path.

Snippets

.vscode/poetry.code-snippets holds one snippet per poetry_* helper, generated from the committed registry so it never drifts from the shipped catalog. Type a helper name and the snippet expands with the real variant and size values as a choice list, a block form for components that compose through slots, and inline for atoms. One file works in VS Code, Cursor, and Windsurf.

HTML+ERB tooling

Rails 8.2 made Herb its ERB engine, and Poetry's templates are gated to parse and compile under it, so the whole Herb toolchain works on a Poetry app: the language server (VS Code's Herb LSP extension, built into Zed's Ruby extension, @herb-tools/language-server for Neovim), the linter, and the render-graph check. Stimulus LSP runs on the same language service and reads data-controller in ERB and tag.div data: { controller: } alike. It resolves controllers from your app, not from a gem, so poetry:editor lists Poetry's identifiers in .stimulus-lsp/config.json and a hand-written poetry--core--sheet#close is never an "invalid controller"; bin/rails poetry:check is what validates those, data: keywords on Poetry helpers included (the Stimulus guide covers composing your controllers with Poetry's).

poetry:editor writes the one config all of it reads, and keeps yours if you have one. Two rules start off: the linter still misreads slot setters on a builder a Poetry helper yields (card.with_title inside poetry_card do |card|) and brace-form setters; both are tracked upstream and the pinned version means an upgrade never switches rules on behind you.

The formatter is still an upstream preview; Poetry's own templates are not run through it, because it rewraps the inline one-liners the components depend on. Run it on your views if you like the output.

Design tools

With the Poetry MCP wired alongside a Figma or Paper MCP, an agent can translate a design into Poetry components; the poetry-design skill's figma and paper references are the rulebook. Design tokens come in through the same AA-gated importer a DESIGN.md uses:

A swatch that fails WCAG AA is dropped and reported with the nearest passing value, never shipped.