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wtf is open-ultra?

numinous-technology/open-ultra — explained in plain English

Analysis updated 2026-05-18

2PythonAudience · developerComplexity · 3/5LicenseSetup · moderate

TL;DR

open-ultra is a proxy that sits in front of your coding AI assistant and gradually shifts requests to cheaper AI models once they prove they match your main model's quality, cutting API costs.

Mindmap

mindmap
  root((open-ultra))
    What it does
      Routes AI requests to cheaper models
      Grades cheap models against main model
      Turns on routing once proven
    Tech stack
      Python
      uv tool install
      Anthropic and OpenAI compatible APIs
    Use cases
      Cut Claude Code API costs
      Compare cheap vs frontier models
      Automate cost savings
    Audience
      Developers using coding agents
      Ops and DevOps
      Cost conscious teams

Code map

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Why would anyone build with this?

REASON 1

Reduce your Claude Code or Codex API bill by routing easy tasks to cheaper models automatically.

REASON 2

See a report of how often cheap models match your main model's quality before trusting them with real traffic.

REASON 3

Run coding agent traffic through a local proxy that keeps all data and trained routing on your own machine.

REASON 4

Test whether budget-tier models can handle your specific coding workload before switching over fully.

What's in the stack?

PythonuvAnthropic APIOpenAI APIOpenRouter

How it stacks up

numinous-technology/open-ultra0-bingwu-0/live-interpreter010zx00x1/faresnipe
Stars222
LanguagePythonPythonPython
Setup difficultymoderatemoderateeasy
Complexity3/52/52/5
Audiencedevelopergeneralgeneral

Figures from each repo's GitHub metadata at analysis time.

How do you spin it up?

Difficulty · moderate Time to first run · 30min

Requires a uv install, an API key for your frontier model, and running openultra init before routing can be trusted.

Use, modify, and distribute freely, including commercially, as long as you keep the license notice and attribution.

Wtf does this do

open-ultra sits between your coding assistant, such as Claude Code, and the AI model it talks to, with the goal of quietly switching some of your requests over to cheaper AI models once it has proven those cheaper models can match the quality of your usual, more expensive one. This is meant to save money on API costs without you having to notice a drop in quality. Here is how it works in practice. Every request from your coding agent still goes straight through to your main, expensive model exactly as before, so nothing about your day-to-day experience changes at first. At the same time, a hidden copy of each request is also sent to one or more cheaper models running in the background. A separate judge model then compares what the cheap model produced against what your main model actually did, either by comparing answers directly, or, for coding tasks, by letting the cheap model work in an isolated, throwaway copy of your project and comparing the resulting code changes. Once a cheap model has built up enough of a track record of matching the main model on a particular kind of task, you can turn on live routing, and the tool will start sending that type of request to the cheap model instead, only falling back to the expensive model for tasks the cheap one has not proven itself on yet. The tool is installed as a command-line program and works with several existing coding assistants, including Claude Code, Codex, and OpenCode, either by launching them through a wrapper command for a single session or by editing their settings so every future session is routed through the tool automatically. Setup involves an initial configuration step to add an API key and choose a starting set of cheap models, after which you can check reports on how often the cheap models are matching your main model and how much money that would save, before deciding whether to turn routing on. All the collected data and trained routing decisions stay on your own machine rather than being sent anywhere else. The project is licensed under the Apache 2.0 License.

Yoink these prompts

Prompt 1
Walk me through installing open-ultra with uv and running openultra init to set it up for Claude Code.
Prompt 2
Explain how open-ultra decides when a cheap model is allowed to handle my requests instead of the frontier model.
Prompt 3
Show me how to check openultra report to see potential savings before turning on live routing.
Prompt 4
Help me set up openultra attach claude so every future Claude Code session routes through the proxy automatically.

Frequently asked questions

wtf is open-ultra?

open-ultra is a proxy that sits in front of your coding AI assistant and gradually shifts requests to cheaper AI models once they prove they match your main model's quality, cutting API costs.

What language is open-ultra written in?

Mainly Python. The stack also includes Python, uv, Anthropic API.

What license does open-ultra use?

Use, modify, and distribute freely, including commercially, as long as you keep the license notice and attribution.

How hard is open-ultra to set up?

Setup difficulty is rated moderate, with roughly 30min to a first successful run.

Who is open-ultra for?

Mainly developer.

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