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RelayRouter

Thanks to RelayRouter for sponsoring this project! RelayRouter is a multi-protocol AI API relay — one key, many models. It speaks both the OpenAI /v1/chat/completions and Anthropic /v1/messages wire protocols and dispatches by API-key group: Claude · GPT-5.x · Codex · Gemini · DeepSeek · Kimi · MiniMax — at 0.5×–5.5× upstream pricing depending on the group. OpenSeek ships first-class support via two built-in providers (relayrouter + relayrouter-anthropic), pinned to the top of the picker. Register here to get started.

Why OpenSeek?

Modern AI coding tools — Claude Code, Codex, Cursor — are great but closed-source and lock you to specific providers. OpenSeek gives you the same agentic terminal experience, open-source, with full BYOK freedom across 28 built-in providers and a transparent cost meter.

• 28 built-in providers — OpenAI-compat (Mikan, DeepSeek, OpenRouter, Groq, Fireworks, NVIDIA NIM, Together, Cerebras, DeepInfra, Perplexity, Mistral, xAI, Cohere, Vercel Gateway, Novita, SGLang, vLLM, MiniMax, RelayRouter), Anthropic-protocol (Anthropic, Bedrock, Vertex, Azure Foundry, RelayRouter-Anthropic), Google (Gemini, Vertex), and local (Ollama, custom)
• 50+ tools, 100+ slash commands — file ops, shell, web search, MCP fan-out, plan-mode tree, sub-agents, RLM
• Plan / Agent / YOLO modes — read-only planning → confirmed execution → full autonomy
• MCP client — stdio / SSE / websocket transports, 1-click skills/server install
• LSP feedback — tsserver, rust-analyzer, pyright, gopls, … inline diagnostics during edits
• Headless HTTP/SSE runtime API — openseek serve --http for IDE bridges & CI
• Cost meter — per-model $/Mtok pricing, real-time spend tracking, cache-hit accounting

Requirements

• macOS or Linux (Windows: use WSL2)
• Bun ≥ 1.3 — required at runtime, not optional. The codebase uses Bun.spawn / Bun.serve / Bun.file; node alone cannot run it. Even if you install via npm i -g, the openseek command shells out to bun at startup and will fail with env: bun: No such file or directory if bun is not on your PATH.

Quick Start

1. Install bun (skip if already installed)

curl -fsSL https://bun.sh/install | bash   # any Unix
brew install oven-sh/bun/bun               # macOS (Homebrew)

Verify: bun --version should print ≥ 1.3.0.

2. Install openseek

Pick one. All three put openseek on your PATH.

# A. npm
npm install -g openseek

# B. bun (same registry as A, smoother if you already use bun)
bun add -g openseek

# C. From source (recommended while iterating)
git clone https://github.com/LichAmnesia/openseek.git
cd openseek
bun install
bun run build
ln -sf "$PWD/bin/openseek" ~/.local/bin/openseek

3. Run

openseek               # start the TUI
openseek setup         # first-run wizard — pick provider + paste API key
openseek doctor        # print resolved config + per-field source layer
openseek serve --http  # headless HTTP/SSE on :7117

4. Pick a provider (RelayRouter recommended)

The fastest way to try every model family from one key: register a RelayRouter account, copy the key, pick a group on the dashboard, and point OpenSeek at it.

# Claude family — key on a "Claude" group (e.g. Claude 2x)
OPENSEEK_PROVIDER=relayrouter-anthropic \
OPENSEEK_API_KEY=sk-... \
OPENSEEK_MODEL=claude-sonnet-4-6 \
  openseek

# GPT / Codex — key on the "Codex 0.75x" group (most permissive)
OPENSEEK_PROVIDER=relayrouter \
OPENSEEK_API_KEY=sk-... \
OPENSEEK_MODEL=gpt-5.4 \
  openseek

→ Sign up here to get RelayRouter credit.

Configuration

OpenSeek resolves each setting (provider / model / API key / base URL) from the highest layer that defines it. Higher layers override lower ones.

#	Layer	Location	Notes
1	env	OPENSEEK_PROVIDER, OPENSEEK_MODEL, OPENSEEK_API_KEY, OPENSEEK_BASE_URL	Plus provider-specific keys (DEEPSEEK_API_KEY, ANTHROPIC_API_KEY, etc.)
2	project overlay	<workspace>/.openseek/config.toml	Sandboxed — only model is honored. api_key / base_url / provider are silently dropped so a checked-in overlay can't leak secrets or hijack the provider.
3	user config	~/.openseek/config.toml	Persisted by the first-run wizard (openseek setup). 0600 perms.
4	default	hard-coded fallbacks	What ships in the binary.

Run openseek doctor to see exactly where each value resolved from:

$ openseek doctor

Resolved configuration:
  provider   deepseek                       ← user (~/.openseek/config.toml)
  model      deepseek-v4-flash              ← user (~/.openseek/config.toml)
  api_key    sk-a…b8e2                      ← env
  base_url   (provider default)             ← built-in default

Precedence (highest first):
  1. env       OPENSEEK_PROVIDER / OPENSEEK_MODEL / OPENSEEK_API_KEY / OPENSEEK_BASE_URL
  2. project   <workspace>/.openseek/config.toml  (model only — secrets ignored)
  3. user      ~/.openseek/config.toml
  4. default   built-in fallbacks

Inside the TUI, /help lists all slash commands grouped by category; /help <name> shows details for one command, /help <category> filters to a single category (session / config / tools / git / agent / skills / diagnostics / advanced / …), and /help all is a flat list.

Develop

bun install
bun run dev          # boots the CLI directly from TypeScript sources, no build needed

Verify

bun run lint        # biome
bun run typecheck   # tsc --noEmit
bun run test        # bun test
bun run verify      # all three

Repo layout

openseek/
├── packages/         14 workspace packages
│   ├── core/         shared leaf utilities
│   ├── provider/     28 provider adapters (Vercel ai SDK)
│   ├── session/      main agent loop + compaction strategies
│   ├── tool/         built-in tool registry
│   ├── command/      slash-command registry
│   ├── tui/          @opentui/solid terminal renderer
│   ├── mcp/          MCP client (stdio / SSE / websocket)
│   ├── skill/        skill loader
│   ├── agent/        sub-agents + RLM fan-out
│   ├── memory/       SessionMemory
│   ├── plugin/       plugin protocol
│   ├── server/       HTTP / SSE runtime API
│   ├── lsp/          LSP client (tsserver, rust-analyzer, pyright, ...)
│   └── cli/          entrypoint
├── scripts/          init / build / lint / typecheck / test / verify
├── tests/            cross-package smoke / e2e / coverage gate
├── install/          curl-bash installer + Brewfile + Nix expression
├── bin/openseek      executable shim
└── package.json      bun workspaces root

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License

MIT — see LICENSE.