**Summary for practitioners:** fx is Vercel's terminal-based AI coding agent, written in Zig, released August 2026. It's open-source (Apache 2.0) and positions itself as "tiny" and "embeddable." Core capabilities include MCP support, basic Git integration, multi-file editing, sandbox/permissions, multimodal input, web search, and local model support. It connects to Vercel's AI Gateway, supporting models from OpenAI, Anthropic, Google, DeepSeek, and others. Authentication flows through Vercel login or bring-your-own-key. Pricing is free or usage-based (0–$20/mo on the gateway). The install is a curl script from fx.sh. Notable gaps: no IDE integration beyond terminal, no voice mode, no auto-test running, no extension hooks. The page itself is a reference table on Terminal Trove (a directory site), so you get structured metadata but no hands-on review, architecture details, or performance claims. The source doesn't explain what "embeddable" means technically or how the sandbox works in practice. One sharp question: if it's meant for terminal-only use, what does "embeddable" actually refer to—or is this a forward-looking claim?