# Dirac — Open-Source Coding Agent Tops Terminal-Bench-2 on Gemini 3 Flash Preview

> A solo-built Cline fork takes #1 on Terminal-Bench-2 with a Flash-tier model — the harness, not the model, was the bottleneck.

- Org: Dirac Delta Labs
- Date: 2026-04-28
- Category: repo, tool
- Source: https://github.com/dirac-run/dirac
- Canonical page: https://ai-tldr.dev/releases/dirac-run-coding-agent/

## In short

A Cline fork hits #1 on Terminal-Bench-2 with 65.2% running on Gemini 3 Flash Preview, edging out closed-source Junie CLI (64.3%) and the official Google harness baseline (47.8%). Apache-2.0, 937 stars in days.

## What it is

Dirac is an open-source CLI and VS Code coding agent forked from Cline by Dirac Delta Labs. The author submitted a Show HN on April 28 reporting Dirac scored 65.2% on the public Terminal-Bench-2 leaderboard using Gemini 3 Flash Preview, putting it ahead of closed-source Junie CLI (64.3%) and well ahead of Google's own harness baseline (47.8%) on the same model.

## How it works

Three key tricks stack: hash-anchored edits identify code regions by content hash so the model never re-reads unchanged context; AST-native patching emits syntactically valid edits the agent doesn't have to retry; multi-file batching collapses several reads or edits into a single tool round-trip. Native tool calling only — no MCP. Custom skills load via an agents.md format.

## Why it matters

It is a clean experimental data point that the agent harness — not the underlying model — is gating Terminal-Bench scores: a Flash-tier model in a tight harness beat agents running on much more expensive backends. Useful both as a low-cost day-to-day coder and as a reference design for harness builders.

## Who it's for

developers who want a low-cost CLI coding agent and harness authors looking for ideas worth copying.

## Try it

npm install -g dirac-cli

## Links

- [GitHub Repo](https://github.com/dirac-run/dirac)
- [Project Site](https://dirac.run/)
- [Show HN](https://news.ycombinator.com/item?id=47920787)
- [Leaderboard Discussion](https://huggingface.co/datasets/harborframework/terminal-bench-2-leaderboard/discussions/145)