Backboard Open-Sources R-CLI Coding Agent That Outscored All Terminal Bench 2.1 Entries

Backboard has released R-CLI, its AI coding harness, under the MIT license, making it freely available for anyone to run using their own API keys. The tool is built on a recursive engine called RLM, which breaks coding tasks into smaller bounded contexts handled by child agents rather than relying on a single large context window. Using R-CLI with Claude Opus, the company recorded an 85.4 percent score on Terminal Bench 2.1, surpassing the same model's published score of 78.9 percent via Claude Code and exceeding all 17 other listed entries, though the run has not yet been submitted for official judge review. A separate test using Moonshot AI's Kimi K2 model via OpenRouter achieved 91 percent accuracy across 89 tasks at a total cost of just $28.72, suggesting frontier-level coding performance may be achievable at a fraction of typical costs. The repository is available on GitHub, and the project requires only Bun, Git, and ripgrep to build from source.