Lucid Train compared with Gemini CLI.
Stated up front: Gemini CLI is not a supported engine. Gemini models are reachable another way.
Gemini CLI is Google's open-source terminal agent under Apache 2.0, notable for a free tier of 60 requests a minute and 1,000 a day on a personal Google account, a 1M token context window on Gemini 3 models, and MCP support. One thing to state plainly rather than bury: Lucid Train cannot use Gemini CLI as an engine. Its harness supports Claude Code, Codex, Cursor CLI and OpenCode only. You can reach Gemini models through the bundled engine via OpenRouter, but that is a different thing from driving Google's agent.
What Lucid Train does not do here
There is no Gemini harness. The engine list is Claude Code, Codex, Cursor CLI and OpenCode, and anything outside it is rejected rather than partially working. This page exists partly to answer that question directly, because it is asked often enough that leaving it implied would be unhelpful.
How you can still reach Gemini models
The bundled engine talks to OpenRouter with your own key, and Gemini models are available there. That gives you the model inside Lucid Train's own agent loop, with role routing across Plan, Edit and Vision. What it does not give you is Google's agent, its tool loop or its free tier, which are properties of the CLI rather than of the model.
The free tier is a real advantage
Worth saying without hedging: 1,000 requests a day on a personal Google account is a genuinely generous free allowance, and no route through Lucid Train reproduces it. If cost is the binding constraint and you are happy in the terminal, Gemini CLI is a strong answer and this page is not arguing otherwise.
What Lucid Train adds that a terminal agent does not
An architecture diagram generated from the repository by a layout solver, convertible into an implementation specification; a dependency audit that also scans your MCP configuration; a Grafana connection; and one approval and diff-review gate across whichever engine is running. Those are the reasons to add an application, and they are unrelated to which model is underneath.
Side by side
| Lucid Train | Gemini CLI | |
|---|---|---|
| Usable as a Lucid Train engine | Not applicable | No |
| Licence | CLI open source; app paid | Apache 2.0 |
| Free tier | CLI free and open source | 1,000 requests a day |
| Models | Any provider, or a CLI engine | Gemini |
| MCP support | Yes, stdio | Yes |
| Architecture diagrams | Yes | No |
| Runs on local models | Yes | No |
| Price | CLI free and open source; desktop $3/month, 7-day trial, no card | Free tier, then your Google plan |
Questions
Related
- Lucid Train vs OpenHandsA platform with many surfaces, against a harness built around one idea.
- Lucid Train vs draw.ioOne generates the diagram from your code and solves the layout. The other is a blank canvas and a shape library.
- Lucid Train vs EraserThe 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 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.
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