firstmate

Running one coding agent is a solved problem. Running three simultaneously — each on a different project area, each producing clean output without stomping on the others — is where most setups collapse into tab chaos. firstmate addresses this by introducing a crew model: one agent you talk to dispatches and supervises a set of autonomous coding agents, each operating in an isolated git worktree. You give a high-level directive; the first mate breaks it apart, assigns work, and manages the crew’s output so you receive PRs or reports rather than half-finished terminals.

The worktree isolation is the architectural decision that separates firstmate from a simple wrapper around parallel agent calls. Each crew member gets a clean branch context, which means two agents working on adjacent parts of the codebase do not produce merge conflicts mid-run. The vendor describes this as ‘non-colliding worktrees,’ and it is what makes parallel investigation and audit tasks tractable — an agent can read and probe one part of the repo without touching another agent’s working state.

firstmate is a self-hosted, open-source tool released under MIT license with no hosted offering and no API surface. That is a deliberate tradeoff: teams that want full control over where the agents run and what they touch can deploy it without negotiating vendor access. The tradeoff is that teams needing to trigger agent crews programmatically from a CI system or external orchestrator have no built-in hook — they are writing shell integrations against a tool not designed for that use case. The fit is strongest for developer-facing workflows where a human is present to talk to the first mate and review what the crew produces before it ships.