Kata
UML class diagrams that are the code.
Kata reads your solution directly, renders it as an interactive class diagram, detects code smells, and drives whole refactorings — Fowler catalog plus your own AI-assisted intents — right from the diagram surface. Changes flow back into the source, so the diagram stays a live view of the code, not a static picture.
Kata.slnx — 57 types, 57 relationships.What it does
Live class diagram
Opens a real .sln or .slnx — no
hand-drawn boxes. Sugiyama layout, namespace clusters, MSAGL rectilinear
edges with proper extends/implements labels.
Cross-language Ctrl+Click
Jumps from a member name to its definition across C# ↔ C++/CLI boundaries. Custom C++/CLI parser + Roslyn hybrid resolver.
Fowler refactoring catalog
Extract Method / Interface / Superclass / Hierarchy, Rename, Move Method, Convert Procedural to Objects — over 30 refactorings, each surfaced on the diagram and callable via MCP so external AI agents can drive them.
Code smell analyzer
24 Fowler smells — Large Class, Long Function, Data Clumps, Feature Envy, Message Chains, and friends — badged as 💩 right on the class node.
AI diff apply
Right-click a smell → ask Claude / Codex → get a unified diff → preview → apply. The diagram adapter updates incrementally, no full sln reload.
Uses your own AI subscription
No API fee on top of the app. Kata invokes your local Claude Code / Codex CLI. You control the model and the cost.
Community and Pro
| Community | Pro | |
|---|---|---|
| License | PolyForm Noncommercial (source-available, free for noncommercial use) | Commercial (proprietary plugin) |
| Editor / diagram | Full | Same base |
| Fowler refactorings | All 30+ | All 30+ |
| Code smell badges | All 24 smells | All 24 smells |
| AI diff apply | 10 uses per month | Unlimited |
| Team Collab features | — | Rolling out in 2026 |
| Commercial use | Not permitted | Permitted |
Getting started
Download
Grab the latest Community binary or clone github.com/dhq-boiler/Kata.
Open a solution
File → Open Solution (.sln / .slnx). Works with C# projects and C++/CLI (.vcxproj referenced from a .sln).
Refactor from the diagram
Right-click a node or member to open a refactoring, or click a 💩 badge and let AI propose a diff you can preview and apply.