Cosine vs. fx (by Vercel)

Feature	Cosine	fx (by Vercel)

Tagline	Your coding agent in your terminal.	Tiny, open, embeddable, native coding agent by Vercel.
Website	https://cosine.sh/cli	https://fx.sh
Language	go	zig
Release Date		August 17, 2026
Last Updated	September 4, 2026	August 19, 2026
Provider Type	AI Lab	Independent
MCP Support	Yes	Yes
Multi-Agent Support	Yes	No
Git Integration	deep	basic
Multi-File Editing	Yes	Yes
Auto Test Running	Yes	No
Sandbox / Permissions	Yes	Yes
Image / Multimodal Input	Yes	Yes
Voice Mode	No	No
IDE Integration	VS Code	None - Terminal only
Hooks / Extensions	Yes	No
Web Search	Yes	Yes
Local Model Support	No	Yes
Context Window	Model dependent	Model-dependent
Supported Models	Lumen Scout, Lumen Outpost; GPT-5.5/5.4, Claude Opus 4.7/4.6, Claude Sonnet 4.6, Gemini 3.1 Pro, Gemini 3 Flash, Kimi K2.6, GLM 5.1, MiniMax M2.7, Qwen 3.6 Plus, DeepSeek v4 Pro	All Vercel AI Gateway supported models, including OpenAI, Anthropic, Google, DeepSeek, z.AI, Moonshot, etc
Pricing Model	Usage Based, Freemium, Subscription	Free, BYOK, Usage Based
Free Tier	No	No
Price Range	$19-999/mo	0 - $20 / mo / Custom (Vercel AI Gateway)
Source Code Availability	Proprietary Software	Open Source (Apache-2.0)
Source Code	N/A	https://github.com/vercel-labs/fx
Development State	active	active