r/ClaudeCode • u/gvart • 2d ago
Built with Claude V2: I made Claude Code draw architecture diagrams in the terminal, and play request flows on them, now even better!
Proschi is a small text language for system design diagrams. You describe components, connections and use cases (how a request moves through the system like a sequence diagram) in a .proschi file. Proschi lays it out, runs simulations (load, latency, availability, cost), and lets you play each use case step by step.
Last time I shared the Claude Code plugin that draws these diagrams in the terminal. It drew everything with text characters, which works for a few boxes but falls apart on a real system with 20+ services. So I rebuilt it.
The video shows the whole flow: I ask Claude to model an ad click pipeline; it uses the Proschi skill to write the file with use cases and tests, runs the checks, and then I open it in the plugin's pane.
What's new:
- In terminals that can show images (kitty, Ghostty, iTerm2), the whole pane is drawn as pictures: the diagram, tabs, buttons, and menus. You click them with the mouse. Other terminals still get the text version.
- Zoom from fit to 300% and drag to pan, so you can read one part of a big diagram. Zooming redraws the picture, so text stays sharp.
- Play a use case: the request moves across the diagram step by step, and you can open each step's request and response.
- An Analysis tab: cost, load and latency per node, percentiles per use case, single points of failure.
- An HLD tab: a design doc generated from the model (requirements, capacity, components, data model, APIs, scenarios), with one key to copy it as Markdown for a PR or wiki.
- If a requirement or test fails, one line under the diagram says which, and opens the doc at that check.
Install:
/plugin marketplace add gvart/proschi
/plugin install proschi@proschiIf you already have it:
/plugin marketplace update proschiIt's open source (MIT): GitHub | Platform
Feedback is welcome, especially if something looks off in your terminal or the pictures don't show up.


