@three-ws/brain-mcp

Any model, one interface — discover LLM providers and run chat completions through the three.ws multi-provider router, from any AI agent.

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A Model Context Protocol server that gives any AI assistant the three.ws multi-provider LLM router over stdio. Discover which models are available — Claude, GPT-4o, o3, Qwen, DeepSeek, NVIDIA Nemotron, IBM Granite, and more — and run a chat completion through whichever one fits, without wiring each vendor SDK yourself.

The router fronts every provider behind one endpoint and transparently falls back across mirrors and free tiers if the chosen model is briefly down. The free open-weight tiers (GPT-OSS 120B, NVIDIA NIM models) work with no key; the paid first-party flagships unlock with a three.ws API key.

Install

npm install @three-ws/brain-mcp

Or run with npx (no install):

npx @three-ws/brain-mcp

Quick start

Claude Code, one line:

claude mcp add brain -- npx -y @three-ws/brain-mcp

To unlock the paid flagships, pass your three.ws API key:

claude mcp add brain -e THREE_WS_API_KEY=sk_live_… -- npx -y @three-ws/brain-mcp

Claude Desktop / Cursor (claude_desktop_config.json or mcp.json):

{
	"mcpServers": {
		"brain": {
			"command": "npx",
			"args": ["-y", "@three-ws/brain-mcp"],
			"env": { "THREE_WS_API_KEY": "sk_live_…" }
		}
	}
}

Inspect the surface with the MCP Inspector:

npx -y @modelcontextprotocol/inspector npx @three-ws/brain-mcp

Tools

Tool	Type	What it does
list_providers	read-only	List every LLM the router can reach — key, network, tier, max output, live availability, and whether it needs auth.
chat	read-only	Run a chat completion through the chosen provider; returns the full reply, the route taken, token usage, and timing.

Both tools read live data — the provider set and completions vary between calls, so neither is idempotent. chat does not mutate any platform state, so it is annotated read-only.

Input parameters

list_providers — no parameters.

chat — messages (required: array of { role: "user" | "assistant", content }), provider (provider key from list_providers, default gpt-oss-120b), system (optional system prompt), maxTokens (optional, 64–16384, clamped to the model's ceiling).

Example

// list_providers
> {}
{
  "ok": true,
  "count": 18,
  "available": 11,
  "default_provider": "gpt-oss-120b",
  "providers": [
    { "key": "gpt-oss-120b", "label": "GPT-OSS 120B", "network": "OpenAI · OpenRouter", "tier": "balanced", "maxOutput": 8192, "available": true, "requiresAuth": false },
    { "key": "claude-sonnet-4-6", "label": "Claude Sonnet 4.6", "network": "Anthropic", "tier": "balanced", "maxOutput": 16384, "available": true, "requiresAuth": true },
    { "key": "deepseek-r1", "label": "DeepSeek R1", "network": "DeepSeek", "tier": "reasoning", "maxOutput": 8192, "available": true, "requiresAuth": true }
    /* … */
  ]
}

// chat
> {
    "provider": "claude-sonnet-4-6",
    "system": "You are terse.",
    "messages": [{ "role": "user", "content": "Name three Solana RPC methods." }]
  }
{
  "ok": true,
  "provider": "claude-sonnet-4-6",
  "model": "Claude Sonnet 4.6",
  "network": "Anthropic",
  "tier": "balanced",
  "routed_via": null,
  "content": "getBalance, getAccountInfo, getSignaturesForAddress.",
  "usage": { "input_tokens": 24, "output_tokens": 14, "total_tokens": 38 },
  "timing_ms": { "first_token": 412, "total": 980 }
}

routed_via is null when the requested provider answered directly; otherwise it names the mirror or free-tier route the router fell back to (so you always get an answer even if the first choice is briefly down).

Model availability is dynamic. Always call list_providers first rather than hardcoding a key — the current Claude ids are claude-fable-5, claude-opus-4-7, claude-sonnet-4-6, and claude-haiku-4-5, but the live list is the source of truth.

Authentication

Model class	Needs a key?
Free open-weight tiers (GPT-OSS 120B, NVIDIA NIM: Nemotron / Kimi / Llama 4)	No
Paid first-party flagships (Claude, GPT-4o, o3, Qwen Plus, DeepSeek, …)	Yes — set THREE_WS_API_KEY

Create an API key at three.ws/account. Without it, paid models return a sign-in error and list_providers flags them with requiresAuth: true.

Requirements

• Node.js >= 20.
• Network access to https://three.ws (or your own THREE_WS_BASE).

Environment variables

Variable	Required	Default	Purpose
THREE_WS_BASE	no	https://three.ws	API base URL (override to self-host or target a preview).
THREE_WS_API_KEY	no	—	Bearer credential that unlocks the paid first-party flagships.
THREE_WS_TIMEOUT_MS	no	120000	Per-request timeout (completions stream server-side).

Links

• Homepage: https://three.ws
• Changelog: https://three.ws/changelog
• Issues: https://github.com/nirholas/three.ws/issues
• License: see LICENSE

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_{Part of the three.ws SDK suite — 3D AI agents, on-chain identity, and agent payments.
Website · Changelog · GitHub}

License

All rights reserved. See LICENSE.