Driving Coding-Agent Sessions

Overview

You can launch coding-agent sessions — Claude Code, Codex, or Pi — as "workers" in tmux, send them prompts, wait for them to finish, read their output, and hand them off to a human. Workers run with permissions bypassed, so they execute tool calls without prompting. Each worker emits lifecycle events to a JSONL file so the controller can observe what it's doing — Claude and Codex through their hook systems, Pi through a native extension csd loads into it.

All operations go through a single CLI: csd. After launching a worker, the controller receives a shim path at /tmp/csd-workers/bin/<tmux-name> that bakes in the worker handle. Every per-worker operation goes through that path — no positional state to thread between calls, no absolute skill path to prepend. A small set of environment variables tune behavior; see Environment variables at the bottom.

(The worker dir moved from /tmp/claude-workers to /tmp/csd-workers; when the default path is in use, csd creates a back-compat symlink /tmp/claude-workers → /tmp/csd-workers, so old paths and muscle memory still resolve.)

The shim path is deterministic: if you pick a memorable tmux name at launch, you can reconstruct /tmp/csd-workers/bin/<tmux-name> whenever you need it. For agents driving via tool calls, that's the right model — shell state doesn't persist between calls, so a SHIM=...; $SHIM cmd pattern just adds noise. The examples below use the bare path.

Harnesses

Pick a harness with --harness at launch (default claude):