Composer – Diagram Your Codebase with MCP
MCP wrapper around codebase diagramming when Mermaid and PlantUML already exist.
Visual architecture modeling for AI agents. Edit C4 diagrams in a drag-and-drop editor. AI reads, modifies, and implements the same model through built-in MCP server.
C4 diagrams as shared context for AI agents beats prompt drift.
Developers using AI coding assistants like Claude Code or Cursor
Lucidchart · Structurizr · IcePanel
The idea for Scryer is to provide a visual surface using C4 model diagrams to share with an AI so that we both understand the actual state of a codebase, and how proposed changes would affect it. It's basically model-driven development (like UML) but adapted for the LLM era. Because of that, I think using opinionated C4 (https://c4model.com/) is the best approach:
- It's simple enough to understand without putting the developer into a coma
- There's just enough context to guide the AI coherently
- Doesn't try to replace code, but defines structural guardrails and scope
Also, I've included some newer agent-oriented methodologies like "always/ask/never" contracts (which have turned out to be very useful), task decomposition, MCP + ACP connections, etc.
This is very experimental and early, so it's quite rough around the edges, but I'm already using it in my own dev workflow and I hope you guys check it out. I honestly think this might be the year of MDE/MDD - as we abstract away the code layer, software architecture fundamentals are becoming more important than ever.
MCP wrapper around codebase diagramming when Mermaid and PlantUML already exist.
Another AI diagram generator when Mermaid AI and Lucidchart already exist.
LLM-generated Excalidraw diagrams that actually lay out correctly using Sugiyama algorithm.
Bidirectional code↔diagram with Claude MCP beats text-only codebase analysis tools.
Agent-powered diagram generation from codebases beats manual C4 modeling.
Napkin keeps everything local while giving you an embeddable MCP endpoint so AI agents can draw and edit diagrams at http://127.0.0.1:21420/mcp. It combines Excalidraw-style hand-drawn tooling (rough.js, connectors, grid snapping, PNG/SVG export) with a Tauri/Rust desktop shell and delta-compressed version snapshots — a neat, concrete take on AI-assisted diagramming, though its impact hinges on MCP adoption and the surrounding agent ecosystem.