Lucid Train compared with Eraser.
The closest competitor in intent, and the clearest split in approach: hosted and prompt-driven on one side, local and repository-aware on the other.
Lucid Train generates architecture diagrams by reading your actual repository, runs as a desktop application against local models so source code never leaves the machine, and can hand the diagram to a coding agent as an implementation specification. Eraser is a hosted browser tool that generates diagrams from a prompt and offers real-time collaboration. The core difference is that Lucid Train starts from your code rather than from your description of it.
It reads the repository, not your description of it
Eraser's DiagramGPT turns a prompt into a diagram, which means the diagram is only as accurate as your memory of the system. Lucid Train surveys manifests, entry points and the import graph and draws what is actually there, which routinely surfaces components people had forgotten and edges nobody had written down. On an existing codebase that difference is the whole comparison.
Local, offline, your own models
Lucid Train is a native desktop app that runs against any OpenAI-compatible endpoint, including a local Ollama model with no API key and no telemetry. Eraser is a browser product, so anything you paste or connect goes to their servers under their terms. For a large number of organisations that single fact settles which tool is usable.
Diagram to code, and other agents as engines
Eraser goes from text to diagram and stops. Lucid Train converts the canvas into a markdown specification and starts a coding turn that returns reviewable diffs, and it can run that turn on Claude Code, Codex, Cursor or OpenCode as the engine. It is also an MCP server itself, so Claude Code and Cursor can call its diagram tools directly.
Depth in the canvas
Four diagram kinds, six themes, seven tier bands, per-node documentation panels, node states that mark single points of failure, story mode with a narrator, 50 versions of history per diagram, and a vision model that checks the rendered canvas and fixes alignment. That is a canvas built for one job rather than a general drawing surface.
What Eraser is good at
Real-time collaboration, which a desktop application does not attempt. Its diagram-as-code syntax is clean and version-controllable, and being browser-based means a teammate opens a link rather than installing anything. For a team that diagrams together on a call, that matters.
Side by side
| Lucid Train | Eraser | |
|---|---|---|
| Generates from a repository | Yes, reads the code | From prompts and pasted snippets |
| Runs fully offline | Yes, with local models | No |
| Source code leaves your machine | No, with a local model | Yes, hosted |
| Bring your own model | Any OpenAI-compatible endpoint | No |
| Diagram to code as a specification | Yes | No |
| Runs other agents as engines | Claude Code, Codex, Cursor, OpenCode | No |
| Works as an MCP server | Yes | MCP server available |
| Export | SVG, 2x PNG, Markdown, .excalidraw | SVG, PNG |
| Version history | 50 versions per diagram | Yes |
| Real-time collaboration | No | Yes |
| Price | CLI free and open source; desktop $3/month, 7-day trial, no card | Free tier, then per seat |
Questions
Is Lucid Train a good Eraser alternative?
For generating and maintaining architecture diagrams from a codebase, yes, and it adds local execution, model choice and the diagram-to-code direction. Eraser keeps the advantage on real-time collaborative editing.
Does Eraser send my code anywhere?
It is a hosted product, so anything you paste or connect goes to their servers under their terms. That is normal for browser tools and is exactly the constraint a local-first desktop app removes.
Can I use Lucid Train from Claude Code or Cursor?
Yes. Lucid Train runs as an stdio MCP server, so its diagram tools are callable from Claude Code, Codex and Cursor directly.
Affiliation
Lucid Train is an independent product and is not affiliated with, endorsed by, or connected to the product described on this page. All names and trademarks belong to their respective owners. Pricing and features were checked on 19 August 2026 and change without notice; check the vendor's own site before deciding.
Related
- Lucid Train vs MermaidMermaid's advantage is that it lives in your Markdown. Its limit is that you are still authoring the diagram by hand, in text, against a layout engine that gives up early.
- Lucid Train vs ExcalidrawThe least adversarial comparison on the site, because Lucid Train's diagrams are Excalidraw scenes.
- Lucid Train vs MiroMiro is a meeting tool that can hold a diagram. This is a diagram tool that generates from your code.
- Lucid Train vs StructurizrStructurizr asks you to maintain a model. Lucid Train reads the code instead.
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