Buildhound

Buildhound turns the Macs and Linux machines a team already owns into clean, single-use GitHub Actions runners, with setup handled by a coding agent such as Claude Code, Codex or Cursor. Each job runs in a fresh virtual machine that is destroyed when the job ends. Jobs go to your machines first, and GitHub-hosted runners remain as the fallback.

What It Is

Buildhound is a self-hosted CI runner service for GitHub Actions. A Mac with Apple silicon, or a Linux machine with KVM, connects to a control plane through the CLI and runs jobs for the shared labels buildhound-macos or buildhound-linux. A Mac can run both macOS and Linux jobs; a Linux host runs Linux jobs. The vendor states that jobs ran about 3x faster on a recent Mac than on GitHub-hosted runners in its own measurements.

How the workflow runs

A machine is registered with npx buildhound runner add. One line in each workflow changes runs-on to read a repository variable that has a hosted default. The Buildhound agent boots a VM from a checksum-verified image, runs the job and destroys the VM afterward. The control plane keeps the variable pointed at your label while a machine can take jobs and clears it when none can, so new jobs route to GitHub-hosted within about two minutes. A job that waits too long for a busy machine is re-run on GitHub-hosted.

Agent-first CLI and MCP server

The CLI prints JSON when not in a terminal, never asks questions, and ends with the next command to run. Commands include setup, scan, runner add, image build, route --apply, runner status and doctor. scan prices every job at GitHub's rates and finds wasted spend, and can open fixes as pull requests. An MCP server exposes the same operations as tools for Claude Code, Codex and Cursor.

Security model

The docs state that the Buildhound agent holds no GitHub credential, each job gets a fresh VM off your network, and jobs that use secrets run only on machines a person has marked Trusted. Jobs from strangers stay on GitHub-hosted runners.

Open-source components

The CLI, MCP server, scan rules, cost model and docs are published under the MIT licence. The control plane, dashboard and machine agent are not in the repository.