Every shipmates crew member runs shell commands. Before any of them runs, it goes through a permission gate. The gate uses the same rule syntax as Claude Code settings: Bash(git status), Bash(rm *), Write(**/.claude/settings.json). The rules are merged from several layers:

Every turn a shipmates crew member takes is a subprocess. It’s claude or the codex app-server. That in turn spawns shells, go test, npm or whatever the task calls for. Two things have to be true about that tree. When a turn ends or gets killed, the whole tree goes, including the grandchildren. And if somebody sets a memory or CPU budget, the budget applies to the whole tree, not just the process I happened to start.

On August 16th a server.test.exe from shipmates climbed to roughly 1 TB of commit charge on my Windows workstation. Windows Terminal was hosting several agent sessions in tabs. It hard-faulted with E_OUTOFMEMORY, and every one of those sessions died at the same moment. It wasn’t the first time either. An earlier one hit about 236 GB through an infinite filepath.Dir loop.

shipmates spends most of its life spawning claude (and codex) processes and reading newline-delimited JSON off their stdout. The last frame of a turn is the important one. It’s a result frame with the cost, the model and the final text. Stderr matters too, because that’s where Claude Code tells you Invalid API key · Please run /login. For a while I was throwing both away under load. The cause is documented right there in the os/exec godoc. I fixed it in one package and then found the…

A few shipmates bugs don’t need a whole post each. They were too good to leave in commit messages, though.

shipmates ships connect to Fleet Command over outbound websocket tunnels. That way nothing on the ship side has to be exposed to the internet. I didn’t write that tunnel layer. I used rancher/remotedialer, the same library Rancher uses to reach downstream cluster agents. I spent years around that code at Rancher, so it was the obvious pick. What I didn’t expect was for my CI’s race job to find two data races in it in the first week.

Since June most of my evenings have gone into shipmates, a Go CLI and daemon for running crews of AI coding agents. I tagged v0.5.0 on August 17th. That was two months and about 240 commits after the first architecture doc. So it’s a good time to write down what it is and why it exists.

shipmates writes a lot of small state files that other processes read. Voyage plans and state, tracker files. Each of them has to be replaced atomically, so a reader sees the old file or the new one and never half of each. Each also has to be replaced durably. When the function returns success, a power cut doesn’t take it back. Every Unix programmer knows the recipe for that. It doesn’t work on Windows, and the reasons are more interesting than “Windows is different”.