toolnexus

We wrote one agent SDK and ported it, by hand, to seven languages — JS, Python, Go, Java, C#, Elixir, Clojure — until the same conformance suite passes byte-identical output in every one of them.

Your LLM, with MCP tools and agent skills built in — in 3 lines, in 7 languages.

Point toolnexus at an mcp.json and a skills/ folder and you get a working agent: the tool-calling loop, skills injection, six unified tool sources, and conversation memory — all included. Vendor-neutral, byte-identical across JavaScript · Python · Go · Java · C# · Elixir · Clojure — the Clojure port is one .cljc tree that runs on both the JVM and cljgo, held to the same full tier as the other six and published to Clojars like the rest.

Right-sized. Not a framework — no builders, advisors, runnables, or config to wade through. Not a toy that falls over the moment you need streaming or a retry. Exactly what a real agent needs — MCP, skills, native + HTTP + built-in tools, remote A2A agents, in-process sub-agents, the loop, hooks, streaming, retries, memory — and nothing it doesn't.

npm i toolnexus                                   # JS / TypeScript
pip install toolnexus                             # Python
go get github.com/muthuishere/toolnexus/golang    # Go
dotnet add package Toolnexus                       # C#
{:toolnexus, "~> 0.18"}                             # Elixir (mix.exs deps)
# Java (Maven): io.github.muthuishere:toolnexus:0.18.1
# Clojure (deps.edn): net.clojars.muthuishere/toolnexus {:mvn/version "0.18.1"} — JVM and cljgo

The insight (borrowed from opencode): MCP server tools, agent skills, your own functions, remote HTTP endpoints, the built-in shell/file tools, remote A2A agents, and in-process sub-agents are all the same thing to an LLM — a named, described, schema'd callable. toolnexus unifies every tool source behind one Tool interface and drives any model with them.

From zero to agent in 3 steps

1. Point at an mcp.json — the standard Claude-desktop-style config:

{
  "mcpServers": {
    "fs":   { "command": ["npx", "-y", "@modelcontextprotocol/server-filesystem", "/data"] },
    "acme": { "type": "remote", "url": "https://api.acme.com/mcp",
              "headers": { "Authorization": "Bearer ${ACME_TOKEN}" } }
  }
}

2. Point at a skills/ folder — **/SKILL.md files with YAML frontmatter, loaded on demand through one skill tool (progressive disclosure).

3. Run.

import { createToolkit, createClient } from "toolnexus"

const tk = await createToolkit({ mcp: "mcp.json", skills: ["skills"] })
const agent = createClient({ baseUrl: "https://openrouter.ai/api/v1", style: "openai", model: "openai/gpt-4o-mini" })

const { text } = await agent.run("Refund order 4021 using the policy.", { toolkit: tk })

The same three steps, in the same shape, in every port — see your language's API reference below.

The seven ports

language	package	API reference
JavaScript / TypeScript	toolnexus (npm)	api/javascript
Python	toolnexus (PyPI)	api/python
Go	github.com/muthuishere/toolnexus/golang	api/go
Java	io.github.muthuishere:toolnexus	api/java
C# / .NET	Toolnexus (NuGet)	api/csharp
Elixir	toolnexus (Hex)	api/elixir
Clojure	net.clojars.muthuishere/toolnexus	api/clojure

Each port's own README covers install and a quick start; everything beyond that is on the docs site.

Documentation

Start here	Quickstart · Concepts · Install
Tool sources	MCP · Skills · Native · HTTP · Built-ins · A2A
The loop	Streaming · Memory · Suspension · Resilience · Observability
Agents	Sub-agents & teams · Personas · Typed decisions (Classifier)
Cookbook	Zero to agent · MCP servers · Agent skills · Judge
Numbers	Performance · Comparison · Judge, live

The contract

SPEC.md is the cross-language contract — §0 is the one-page conformance suite every port must satisfy. A behaviour change lands in all seven ports or it is not done; the shared fixtures in examples/ are what "identical" is measured against.

Changes go through OpenSpec before code. See CLAUDE.md for the workflow, CHANGELOG.md for what shipped, and PUBLISHING.md for how each port is released.

Community

Join the AgentNexus Discord.

License

MIT — see LICENSE.