Dirac: Open-Source Agent Tops TerminalBench with 65.2%, Cheaper and Open

Dirac is an open-source coding agent that just topped the TerminalBench 2.0 leaderboard for gemini-3-flash-preview with a 65.2% score — beating Google's official baseline of 47.6% and the previous top closed-source agent Junie CLI at 64.3%. The run was done fully open-source, with no benchmark-specific AGENTS.md files or other cheating mechanisms. The maintainer submitted a PR to the leaderboard 8 days ago but has not received a response due to backlog.

Key Features

• Hash-anchored parallel edits for efficient and accurate code changes.
• AST manipulation to understand and transform code structurally.
• Context curation to keep context tightly focused, improving accuracy and reducing costs — claims 64.8% average cost reduction vs other agents.
• No MCP (Model Context Protocol) — straightforward tooling.

TerminalBench 2.0 Results

Scored on gemini-3-flash-preview: 65.2% vs Google's 47.6% and Junie CLI's 64.3%. The run was done in a leaderboard-compliant way (no resource or timeout modifications). All code is on GitHub — no difference between what was run and what is public.

Cost Comparison

Dirac's average cost per task across 8 benchmarks (against Cline, Kilo, Ohmypi, Opencode, Pimono, Roo) was $0.18, vs the next best at $0.38. That's a 64.8% reduction, or 2.8x cheaper. For example, Task1 (transformers, 8 files) cost $0.13 vs Cline's $0.37. Task6 (transformers, 25 files) cost $0.34 vs Ohmypi's $0.94.

Installation & Usage

Clone the repo and follow setup instructions in the README.md. The agent runs as a CLI tool. No special setup beyond Node.js and API keys for the chosen model.