Why noeta

This page says what noeta is for, who it is for, what it deliberately is not, and how it relates to Claude Code.

What it is

noeta is an open-source coding agent that behaves, from the model's side, like Claude Code, and is built, from the operator's side, like a server program. It is one Python package (noeta) with a terminal UI (noeta-tui), a web app and a desktop shell on top of the same API.

Two decisions shape everything else:

1. What the model sees follows Claude Code. Models carry their strongest habits on the tools and prompts of the most-used coding agent. noeta sends the same tool names and schemas, keeps the rules and order of Claude Code's prompt parts (in its own words), sends the same reminders and notices, compacts the way Claude Code does, and shapes the provider request the same way. A difference is a bug unless it is listed with its reason (ADR-003, parity/deviations.md).
2. Underneath, a task is an append-only log with one writer. Nothing about a running task lives only in a process. A worker claims a task, folds its log into its state, takes one step and appends what happened. Any worker can continue any task, a crash never repeats a side effect blindly, and a task that waits for a person holds nothing (ADR-001, A task is a log).

What it is for

• Coding agents that run unattended. A task can run for hours, survive a worker being killed or redeployed, and pick up on another machine where its log stops.
• Agents that wait for people. Approvals and questions park the task. Answer from the terminal, the web app, an editor or your own service, minutes or days later.
• Many machines. Point any number of noeta worker processes at one Postgres store and put noeta serve in front; front ends attach to any server (Run it as a server, Many machines).
• Embedding. The same kernel is a Python library: create tasks, watch their events and answer their questions from your own program (Embed it in Python).
• Any model. Anthropic's API, any OpenAI-compatible endpoint (vLLM, gateways, DeepSeek), or OpenAI's Responses API, several at once with each model routed to its provider (Models and providers).
• Programs written for Claude Code. noeta -p speaks Claude Code's headless flags and its stream-json protocol, so a program built on Claude Code's Agent SDK can drive noeta unchanged (The terminal UI and -p).

Who it is for

• Developers who want Claude Code's working style with a model of their choice, in a terminal, an editor or a browser.
• Teams that run coding agents on servers: CI jobs, review bots, long refactors, agents that answer in a chat.
• People who build products on an agent and need its state durable, auditable (the log is the full record) and spread over machines.
• Plugin authors: every capability is a plugin behind one interface, and a plugin can be a single Python file (Write a plugin).

What it is not

• Not Claude Code's code. noeta is a separate implementation. Its prompts are written in its own words; only the rules, their order and the model-visible shapes follow Claude Code.
• Not a reader of Claude Code's files. noeta reads only ~/.noeta/, a project's .noeta/, NOETA.md / AGENTS.md and the machine's managed directory. The formats inside are Claude Code's, so moving over is a copy, but ~/.claude/, .claude/, CLAUDE.md and .mcp.json are never read, so the two tools never run each other's hooks or servers (ADR-004).
• Not multi-tenant. A store and a server serve one party: whoever holds the server's token drives every task, and tools run as the worker's OS user. Separate parties get separate servers and stores, or separation you build on the extension points (ADR-028).
• Not a workflow engine. There is no graph to define. The model decides each step; a fixed procedure is an agent plus sub-agents (or the Workflow tool, as in Claude Code).
• Not a hosted service. It runs in your process, on your machines, against your store. There is no noeta cloud and nothing phones home.
• Not everything Claude Code has. Claude Code plugin monitors, bin/ folders, LSP servers, themes and output styles are not loaded; some hook events belong to Claude Code features noeta lacks and are skipped with a warning. The full list is in Compared with other agents and Known limitations.
• Not on PyPI yet. 1.0 is in development; install it from the repository (Quickstart). The 0.x releases were the separate noeta-runtime / noeta-sdk packages and describe a different codebase.

How it relates to Claude Code

	Claude Code	noeta
What the model sees	the reference	follows it; differences listed in parity/deviations.md and checked by make parity
Settings, hooks, skills, agents, MCP, plugin folders	~/.claude, .claude/, CLAUDE.md, .mcp.json	the same formats in ~/.noeta, .noeta/, NOETA.md / AGENTS.md, .noeta/mcp.json
Environment knobs	CLAUDE_*, MAX_MCP_OUTPUT_TOKENS, …	the same knobs under the NOETA_ prefix
Headless use	claude -p, stream-json, Agent SDK	noeta -p with the same flags and protocol
A conversation	one local session	a task: a log in a store, continued by any worker
A crash mid-tool	the session ends	the next worker continues; the unfinished call is answered "outcome unknown" unless the tool can look its outcome up
Waiting for approval	a process waits	the task parks and holds no worker
Models	Anthropic's	Anthropic's, OpenAI-compatible, OpenAI Responses, several at once
Extending it	plugins, hooks, MCP	the same, plus Python plugins behind one Extension interface
Telemetry	yes, can be turned off	none

How the matching is kept honest — recordings of real Claude Code requests, an offline replay, and a list of accepted differences — is on Matching Claude Code. How noeta compares with pi, DeepSeek Harness and other agents, point by point, is on Compared with other agents.