@three-ws/brain-mcp
v0.1.2
Published
Any model, one interface — the three.ws multi-provider LLM router over MCP. Discover available providers/models (Claude, GPT-4o, Qwen, DeepSeek, NVIDIA Nemotron, IBM Granite…) and run a chat completion through whichever one fits. Free tiers need no key; p
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Readme
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-mcpOr run with npx (no install):
npx @three-ws/brain-mcpQuick start
Claude Code, one line:
claude mcp add brain -- npx -y @three-ws/brain-mcpTo 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-mcpClaude 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-mcpTools
| 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: 1–100 turns of { role: "user" | "assistant", content }, content ≤ 16,000 chars), provider (provider key from list_providers, default gpt-oss-120b), system (optional system prompt, ≤ 8,000 chars), maxTokens (optional, 64–16384, default 4096, clamped to the model's ceiling).
Example
Both responses below are shape illustrations — the live provider set and generations will differ.
// list_providers (example response)
> {}
{
"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 (example response)
> {
"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_providersfirst rather than hardcoding a key — the current Claude ids areclaude-fable-5,claude-opus-4-7,claude-sonnet-4-6, andclaude-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 ownTHREE_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). |
Errors
A failed tool call returns an MCP error result (isError: true) whose text is a single JSON object — { "ok": false, "error": "<code>", "message": "…" }, plus status and detail on upstream rejections:
| error | Meaning | Recovery |
| ------- | ------- | -------- |
| upstream_error | The router rejected the request — status carries the real HTTP code: 400 (bad arguments or an unknown provider key), 401 (paid model without a valid THREE_WS_API_KEY), 429 (rate-limited), 502 (the model's stream failed before producing output). | Act on status; for 401 set a key, for an unknown key re-run list_providers. |
| timeout | No complete response within THREE_WS_TIMEOUT_MS. Long flagship generations can be slow — the default 120 s matches the router's own ceiling. | Retry, lower maxTokens, or pick a fast-tier provider. |
| network_error | The request never reached the router (DNS, offline, TLS). | Check connectivity / THREE_WS_BASE. |
| bad_config | THREE_WS_TIMEOUT_MS is not a positive number (thrown at startup). | Fix the env var. |
If the requested provider fails mid-flight the router transparently falls back to a mirror or free tier and the reply's routed_via names the route taken — you only see an error when every route is exhausted.
Links
- Homepage: https://three.ws
- Changelog: https://three.ws/changelog
- Issues: https://github.com/nirholas/three.ws/issues
- License: Apache-2.0 — see LICENSE
