OpenSeek

What is OpenSeek?

OpenSeek is an open-source TUI (terminal) coding agent built in TypeScript on Bun that gives you the agentic terminal experience of tools like Claude Code or Cursor without provider lock-in: it ships 28 built-in providers with full BYOK freedom, 50+ tools, 100+ slash commands, Plan/Agent/YOLO execution modes, an MCP client, LSP feedback during edits, a headless HTTP/SSE runtime API, and a transparent per-model cost meter — MIT-licensed and installable via npm or bun.

Key features

• 28 built-in providers: OpenAI-compatible (DeepSeek, OpenRouter, Groq, Fireworks, Together, Mistral, xAI, Ollama, vLLM and more), Anthropic-protocol (Anthropic, Bedrock, Vertex, Azure Foundry), and Google Gemini — all bring-your-own-key
• 50+ built-in tools and 100+ slash commands covering file ops, shell, web search, MCP fan-out, plan-mode tree, sub-agents, and RLM
• Three execution modes: Plan (read-only, never writes a file), Agent (confirm-on-write default), and YOLO (full autonomy, auto-approve everything)
• MCP client with stdio, SSE, and websocket transports plus 1-click skills/server install
• LSP feedback in the loop — tsserver, rust-analyzer, pyright, gopls give inline diagnostics during edits
• Headless HTTP/SSE runtime API via `openseek serve --http` (port 7117) for IDE bridges and CI
• Cost meter with per-model $/Mtok pricing, real-time spend tracking, and cache-hit accounting
• Layered config (env > project overlay > user config > defaults) with `openseek doctor` showing where each value resolved from; project overlays only honor `model` so checked-in configs can't leak secrets or hijack the provider
• MIT license — fork it, embed it, sell something built on top of it

Who it's for

• Developers who want a Claude Code / Codex / Cursor-style agentic terminal experience but open-source with full control over which model provider they pay
• Teams routing across multiple model families (Claude, GPT, Gemini, DeepSeek, local Ollama/vLLM) from one CLI with one config surface
• CI pipelines and IDE bridges that need a headless coding agent over the HTTP/SSE runtime API
• Cost-conscious users who want real-time per-model spend tracking instead of an opaque subscription
• Cautious workflows that want a read-only Plan mode before any file is written

When not to use it

OpenSeek requires Bun ≥ 1.3 at runtime (node alone cannot run it) and supports macOS/Linux only — Windows users must go through WSL2. If you want a fully managed product with a bundled model subscription rather than bringing your own API keys, a hosted closed-source agent may fit better.

FAQ