Harnessctl

harnessctl

**One command for Claude Code, Codex, DeepAgents, Gemini, Cursor, OpenCode, and custom coding agents.**

[](LICENSE) [](https://www.npmjs.com/package/harnessctl)

`harnessctl` is a small CLI that lets you run, compare, hand off, and fail over between coding-agent CLIs without changing how you work.

Use it when one agent is better at planning, another is better at editing, and a third is available when the first one hits a rate limit.

Install

npm install -g harnessctl
harnessctl setup

Or use Homebrew:

brew install mnvsk97/tap/harnessctl

Other options:

# Linux / macOS binary installer
curl -fsSL https://raw.githubusercontent.com/mnvsk97/harnessctl/main/install/install.sh | bash

# From source
git clone https://github.com/mnvsk97/harnessctl.git
cd harnessctl
bun install
bun run src/cli.ts --help

Quick Start

# Run the default agent
harnessctl run "fix the auth bug"

# Pick an agent
harnessctl run --agent codex "refactor the database layer"
harnessctl run --agent deepagents "run the tests and fix failures"

# Open an interactive agent shell
harnessctl shell --agent claude

# Check configured agents
harnessctl doctor

Core Workflows

Hand Off Between Agents

Every run gets a run ID. Use it to continue with another agent.

harnessctl run --agent codex "refactor auth"
# run: 1713364500000-codex

harnessctl handoff 1713364500000-codex --agent claude "review and add tests"

The next agent gets a compact handoff: original task, summary, changed files, and a pointer to the full context file under `.harnessctl/handoffs/`.

Compare Agents

Run the same prompt across agents and optionally ask a judge agent to pick the best result.

harnessctl compare "fix this bug" --agents codex,claude
harnessctl compare "fix this bug" --agents codex,claude --judge claude