MIT /open source /C4 · DDD · governance

Architecture that lives here,
and holds whatever builds from it.

One model, built by you or by AI, that becomes the harness for whatever builds from it.

Open Studio in the browser Explore the Hub

Modelled by either Draw it in Studio, chat it with AI, or connect your agent over MCP.

Read as context Agents read boundaries, ADRs and requirements before writing code.

Checked against Scenarios and fitness functions name the tests that prove them; radical check fails CI when code drifts from the model.

Metamodel01 The rules: types, relations, containment. Radical or plain C4, fully editable. Model02 One validated graph. Add an element once, see it in every view. Views03 Structure, Flow, Hierarchy, Table, Matrix and Wiki — six readings of one model. Milestones04 Freeze, compare and restore named snapshots of the model.

Two metamodels

The metamodel is the rulebook: which elements exist, what may sit inside what, and which relations may join them. Studio checks every edit against it, by hand, by AI or over MCP. Pick one when you create a model; both can be extended with your own types.

Radicaldefault C4 with the domain behind it and everything that shapes the architecture, linked element to element: why it exists, what it must do, how it behaves, what it looks like and what was decided. C4 Person · System · Container · Component · Database · Web App · Queue · Group Domain Domain · Entity Requirements Need · Requirement (EARS) · Scenario (Gherkin) States State machine · State · Pseudostate · Event UX Mockup Governance ADR · Fitness function · Blueprint Need ←derives Requirement ←verifies Scenario · Requirement ←satisfies System · ADR constrains→ Container · Fitness function implements→ ADR Every type and relation, explained → C4 Simon Brown's C4 model and nothing else: people, software systems, the containers that run or store data, and the components inside them, joined by one relation, Interacts. For when the diagram is the whole job. C4 Person · System · Container · Component · Database · Web App · Queue Other Group System ⊃ Container ⊃ Component · Person interacts→ System The C4 types and rules →

Also in the box

Governance built in. Raw needs, EARS requirements, ADRs and fitness functions as linked model elements.
AI that edits the model. Validated, undoable patches. Claude, OpenAI, Gemini or Ollama — your key, nothing proxied.
MCP server. Claude Code, Claude Desktop or Codex read and edit a model folder with the same tools as Studio's assistant.
Concept Hub. 120+ ready-made requirements, ADRs, fitness functions, patterns and blueprints.
Smart Layout. Tries twelve layouts, scores each as drawn and keeps the cleanest; curved or orthogonal lines per view.
Rows, columns, grids. Pin elements in line, in the order you picked them. Drags, physics and Smart Layout keep it.
Design, view, present, inspect. Edit, explore read-only, turn views into slides, or see what radical check says about the model.
Plain files, no lock-in. One .radical JSON file or a folder of Markdown — git-friendly.
Desktop, browser or VS Code. Same editor everywhere.

Start from the Hub

Skip the blank canvas — pick concepts and add them to Studio in one click.

Blueprints Patterns Requirements ADRs Fitness Functions

Connect your agent

A local MCP server gives Claude Code, Claude Desktop, Codex or any MCP client the model as tools: read the summary and the metamodel rules, search, add and move elements, create views, sequences and slides, run Smart Layout, keep elements in rows, columns or grids, run Radical Forge stage by stage, save and compare milestones, list the model's issues, read what is selected in Studio, or extend the metamodel with your own types. Every write is checked against the metamodel, and Studio shows it on the open canvas.

Setup & tools → Source →

# Node.js ≥ 20.11 — point it at a Markdown model folder
claude mcp add radical-folder -- npx -y @radicaltools/mcp \
  --folder /path/to/my-model

Run it locally

Node.js ≥ 20.11 — or skip the install and use studio.radical.tools.

GitHub → Releases → Manual →

# clone, install, run
git clone https://github.com/radicaltools/radical.tools.git
cd radical.tools
npm install
npm run dev