AI-agent-driven refactoring platform for real codebases.
Kata exposes Fowler's refactoring catalog and code-smell detection through a Model Context Protocol (MCP) server, so any AI agent — Claude Code, Codex, your own — can drive whole refactorings against a real solution. A class diagram surfaces the same intents in a UI when you want a human-in-the-loop view.
The workflow, in one sentence: an agent reads the smells Kata detected, proposes a diff, you preview it in the app, then apply it back to the source. Changes flow back into the Roslyn workspace / C++/CLI project files, so the diagram stays a live view of the code — not a static picture.
20-second demo: right-click a LongFunction smell on Order.PlaceOrder → Ask AI (Claude) → preview the proposed diff → Apply. The bloated method is decomposed into ValidateInputs / CalculateDiscountRate / CalculateTaxRate / BuildReceipt. See the full 3-minute recording for the complete flow.
- MCP-native — the refactor catalog isn't a plugin, it's the primary surface. 75+ MCP tools cover load-solution, list-smells, propose-*, apply-change-set, quality-delta, so an agent can drive Kata alongside its own tooling.
- Cross-language symbol index — C# ↔ C++/CLI resolution works Ctrl+Click
and refactor-wise across the boundary (the C++/CLI symbol layer in
Kata.Cppreimplements just enough Roslyn semantics to interop). - Whole-codebase Fowler catalog — 47 refactoring intents wired through
a
IIntentApplier<T>strategy pattern, each MSBuild-free unit-testable. - Smell → refactor loop — 24 Fowler smells detected as badges on nodes and members. The AI-fix flow reads the exact smell + local source, produces a unified diff, and hands you a preview dialog.
- Live graph — no sln reload after refactors; the diagram adapter updates incrementally.
- C# projects (via Roslyn) — full symbol semantics, cross-project refs, complete Fowler catalog
- C++/CLI projects — custom Roslyn-flavoured layer in
Kata.Cpp, inline members, macros, hybrid symbol resolution across the C# ↔ C++/CLI boundary - Mixed C# + C++/CLI solutions — the main dogfooding target. Ctrl+Click from a C# call site into a C++/CLI header and back.
- ASP.NET Razor / Web Forms views (as C# flavor) — view pseudo-types with cross-file rename
Additional language adapters (Java / Kotlin / Go / TypeScript) are in development for a future release.
Kata.Mcp is a Streamable HTTP server (per MCP 2026-07-28 spec), stateless by default. Multiple agents can connect simultaneously alongside a running Kata App instance. Common tools:
load_solution list_projects list_types
list_smells get_smell_context propose_rename
propose_extract_method propose_extract_class apply_change_set
get_quality_delta export_test_instruction
apply_change_set in standalone (headless) mode is opt-in via
--allow-headless-apply / KATA_ALLOW_HEADLESS_APPLY=1 — by default a
human confirms the diff in Kata.App's preview dialog first.
Kata is under active solo development by @dhq-boiler. It works well on the codebases it was built against; the surface is wide and the edges are still rough. Bug reports and reproducible examples are the most useful form of contribution right now.
| Community (this repo) | Pro (kata.dhq-boiler.dev/pro) | |
|---|---|---|
| License | PolyForm NC (source-available, free for noncommercial use) | Commercial (proprietary plugin) |
| Editor / class diagram / smell badges (114) | ✅ full viewer | ✅ same base |
| MCP server — read-only tools | ✅ list / get / view smells / policy / perf | ✅ same |
| View proposed refactors (diff preview) | ✅ | ✅ |
| Apply refactors (30+ Fowler) | ★ 14-day free trial, then view-only | ✅ unlimited |
| Cross-language find refs / rename | ★ 14-day free trial, then view-only | ✅ unlimited |
| AI diff apply (bring your own AI CLI) | ★ 14-day free trial, then view-only | ✅ unlimited |
| Governance report export | ★ 14-day free trial, then view-only | ✅ unlimited |
| License upgrade | — | Paste key in Preferences → Pro; Pro DLL auto-downloads via Pro channel |
| Pricing | Free | $49 buyout / $150 seat·yr / $290 Business seat·yr |
★ The 14-day free trial starts on the first Pro feature use — no signup, no card, no manual install. Everything Pro does works identically during the trial. After the trial, Community stays a full viewer forever. Upgrade any time to keep applying.
Community is the same binary customers install; Pro is a small plugin DLL that
Kata auto-downloads from the license-verified Pro channel
(kata.dhq-boiler.dev/pro-updates/) once a valid Pro license key is present.
There is no separate installer, no manual DLL drop. AI cost is on the user's
own Claude / Codex subscription either way — Pro adds no per-request markup.
Requires .NET 10 SDK and Windows (WPF for the App; MCP host runs headless).
dotnet build Kata.slnx
dotnet test tests\Kata.Tests\Kata.Tests.csproj
dotnet run --project src\Kata.App\Kata.App.csproj
dotnet run --project src\Kata.Mcp.HostApp\Kata.Mcp.HostApp.csprojDefault MCP endpoint: http://localhost:7345/mcp (override with KATA_MCP_URLS).
The Kata.App.Pro/ folder does not live in this tree — it's the private
plugin repo. Community builds fine without it; the ProLoader silently falls
back to NoOpProFeatures.
src/
Kata.Core/ — model, analysis, intents (language-neutral)
Kata.Roslyn/ — C# language adapter (Roslyn)
Kata.Cpp/ — C++/CLI parser + semantics
Kata.Razor/ — Razor / Blazor view adapter
Kata.WebForms/ — ASP.NET Web Forms view adapter
Kata.App/ — WPF frontend
Kata.App.PluginApi/ — public contract shared with the Pro plugin
Kata.Mcp/ — MCP tool definitions
Kata.Mcp.HostApp/ — MCP Streamable HTTP host executable
tests/
Kata.Tests/ — xUnit
Issues welcome. Before opening a PR:
- Run
dotnet build Kata.slnxanddotnet test— both must pass - Match the existing style (no new comments unless they explain a non-obvious why, no dead code, no speculative abstractions)
- Note that this project is licensed PolyForm NC, not MIT — commercial use of contributed code requires the Pro license
PolyForm Noncommercial 1.0.0. Free for personal, educational, research, hobbyist, and other noncommercial use. For commercial use, buy a Kata Pro license.
Copyright © 2026 dhq_boiler.