babysit

A transparent PTY wrapper that runs a shell command and exposes it to external AI agents (Claude Code, Codex, …) via plain babysit subcommands.

$ babysit make local-ci
babysit session ab12: make local-ci
  babysit log -s ab12 --tail 200
  babysit status -s ab12
Running tests...
✓ test_a
✗ test_b: assertion failed
make: *** [local-ci] Error 1
$ echo $?
2

babysit run make local-ci is the explicit form and behaves identically. Use -- (or the run form) when the wrapped command's name collides with a babysit subcommand: babysit -- list or babysit run list.

There is no TUI, no alt-screen, no key grabbing. Output streams straight to your terminal and stays in scrollback. Ctrl-C, Ctrl-Z, Ctrl-D and every other keystroke flow through to the wrapped command exactly as if you ran it directly. Babysit exits with the same exit code as the wrapped command, and to "quit babysit" you just kill the wrapped command (Ctrl-C, exit, etc.).

The session id printed at the top is the only thing babysit adds. Paste it into a Claude or Codex session running in another terminal:

"hey, can you tell me if anything goes wrong on babysit session ab12?"

The agent reads state via the subcommands below. babysit does no monitoring of its own — it just exposes the wrapped command as a small CLI/file API; the agent decides when and how to use it.

Subcommands

babysit [--name NAME] <cmd> [args…]        # wrap a command (bare form)
babysit run [--name NAME] <cmd> [args…]    # wrap a command (explicit form)
babysit list [--json]                       # all sessions
babysit status -s <id> [--json]             # state of the wrapped command
babysit log -s <id> [--tail N] [--raw]      # output (ANSI stripped unless --raw)
babysit restart -s <id>                     # kill + respawn the wrapped command
babysit kill -s <id>                        # terminate it
babysit send -s <id> "<text>"               # write text + newline to its stdin
babysit prune [--dry-run]                   # delete finished / dead sessions

-s <id> is shorthand for --session <id> and accepts either the id, a name set via --name, or the literal string latest. From inside the wrapped command itself the session is implicit via $BABYSIT_SESSION_ID, so the flag can be omitted.

status and log work even after babysit has exited — they fall back to the on-disk state files. restart, kill, and send need the live control socket and will fail if the babysit process is gone.

Session state on disk

Each session writes to ~/.babysit/sessions/<id>/:

meta.json       # static info (cmd, started_at, …)
status.json     # live state (running / exited / killed, exit_code)
output.log      # raw bytes from the wrapped command's PTY
control.sock    # Unix socket the subcommands talk to

babysit list flags sessions whose owning babysit process has died as dead (e.g. crash, kill -9, reboot before a clean exit could be recorded). Run babysit prune to clear out anything that's no longer running.

Build

cargo build --release
# binary at target/release/babysit