EONYX is a terminal AI agent for working with code, written in Go.
It connects straight to any OpenAI-compatible API.
OpenAI, OpenRouter, DeepSeek, Moonshot.
Or a local Ollama, llama.cpp or LM Studio server.
No telemetry, no OAuth.
One process, one binary.

Model Context Protocol (MCP) is an open standard.
Through it an agent reaches external systems: databases, APIs, trackers, anything.
EONYX ships an MCP client built on the official Go SDK, modelcontextprotocol/go-sdk.
Servers are described in eonyx.json, and their tools appear to the model next to the built-in ones.

EONYX is not tied to the cloud.
It speaks to any OpenAI-compatible API.
Point it at a local model server and your code never leaves the machine.
No model key, no model traffic, no cloud.

Every turn starts with the model receiving context.
EONYX builds it from three parts.
AGENTS.md carries the project’s standing instructions.
Sessions hold the full history on disk.
Auto-summarization compacts the older turns as the window fills.

EONYX and Claude Code are both terminal AI agents for code.
The workflow rhymes: MCP, skills, hooks, subagents, plan mode, sessions.
The difference is architecture and freedom.
Claude Code is bound to the cloud and to Anthropic models.
EONYX is not.

A skill is a folder with a SKILL.md inside.
It is an instruction the agent loads when the task calls for it.
Package a repetitive procedure once: a code review, a deploy checklist, a report format.
It then costs no context until it is actually needed.

EONYX talks to any OpenAI-compatible API.
A provider is the way to reach a backend.
A model binds an id to a provider.
Here is how to connect one, hide the secrets and set price, window and retries.

EONYX is written in Go.
It builds into a single static binary.
Inside sits a small set of packages around one central abstraction.
Here is how it fits together.

Hooks are shell commands that run around a tool call.
One before it, one after it.
They bolt on formatting, auditing and guardrails without touching the agent’s code.

An agent reads code, edits it and runs commands.
So it has to stay inside explicit permissions.
EONYX stacks several layers: a static gateway, a file sandbox, plan mode and a hard block on dangerous commands.