> For the complete documentation index, see [llms.txt](https://book.ferro.pro/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.ferro.pro/ai/free.md).

# free

<https://openrouter.ai/openrouter/free>

* 200K Context Length | <https://openrouter.ai/compare/openrouter/free/openrouter/auto>

<https://opencode.ai/docs/zen/#pricing>