I rebuilt my AI coding agent workspace in Rust. It uses 1/15 the memory of the Electron app I replaced

Description and use

Krill, a Rust‑based coding agent workspace, uses 1/15 the memory and 1/27 the CPU of the Electron app Orca, while keeping sessions persistent and lightweight.

Problem

Running multiple coding agents in an Electron app caused excessive memory and CPU usage on a Mac.

Outcome

Krill uses 1/15 the memory and 1/27 the idle CPU of Orca for 10 terminals, with comparable install size and session persistence.

Workflow

• Create a new session with krill new
• Open a repository and spawn worktrees
• Start agents via CLI (Claude Code, Codex, etc.)
• Monitor agent status hooks to queue approvals
• Reconnect to sessions after app restart using krill attach

Evidence

Krill uses 1/15 the memory of Orca's memory at 10 terminals

Source

At 10 terminals: Memory (phys_footprint) 85.9 MiB for Krill, 1,274.9 MiB for Orca

Krill took 7.5 s to finish the burst versus Orca's 4.0 s at 20 terminals

The agent workspace I was using did the job, but it was an Electron app, and with a dozen terminals open it had quietly become the heaviest thing on my Mac.