Local CLI for Claude Code and Codex

Less noise in the context window. Nothing lost.

Fonn opens the native Claude Code or Codex CLI with your saved model profile. It trims recognized noisy shell output before the model reads it, and keeps every original on disk so the agent can read it back.

Install from source See the filter work

Saved profiles

A provider, model and effort level under a short name, so fonn --profile focused always starts the same way.

Subagent guidance

Startup instructions ask the agent to hand meaningful independent work to its built-in subagents. Simple tasks stay with the parent.

Output filtering

Recognized noisy shell output, like test progress rows, is shortened before the model reads it. The full original stays recoverable.

Your CLI, unchanged

Claude Code and Codex keep their own login, settings, permissions and questions. Fonn never bypasses an approval.

Quick start

git clone https://github.com/nord-forge/fonn.git
cd fonn
npm ci --ignore-scripts
npm run build
node packages/cli/dist/cli/main.js claude --cwd /absolute/path/to/project

InstallSource checkout, standalone filters, and the upcoming Homebrew cask.

How the filter decidesStep through every check with real samples or your own output.

Version 0.1.0. MIT licensed. Fonn is independent of Anthropic and OpenAI.