`smolvm 0.8.0 machine exec -t` allocates an in-VM PTY but never
forwards the host terminal's window size — the PTY starts at
`0 0` and host resizes (tmux pane resize, terminal window
resize) go unnoticed, so the claude TUI inside a smolmachines
bottle renders for whatever tiny box it last saw and ignores
operator resizes. `docker exec -it` propagates window-size
changes automatically; smolvm doesn't.
Workaround: a small Python wrapper
(`backend/smolmachines/pty_resize.py`) that interposes between
the operator's terminal and `smolvm machine exec`. It spawns
smolvm as a child, traps host SIGWINCH, and on every resize
(plus once at startup) runs a side-channel
`smolvm machine exec --name <M> -- sh -c 'for f in /dev/pts/*;
do stty -F $f cols X rows Y; done'`. The kernel delivers
SIGWINCH to the in-VM foreground process group when the slave
PTY's size changes, so claude picks up the new dimensions
without extra signalling.
`SmolmachinesBottle.claude_argv` prepends
`[sys.executable, -m, claude_bottle.backend.smolmachines.
pty_resize, <machine>, --, ...]` to the existing smolvm argv
in TTY mode. Non-TTY mode (provisioning shell-outs) skips the
wrapper — no PTY to resize.
The wrapper survives the dashboard's
`_build_resume_argv_with_fallback` shell-wrap because the
split-at-`claude` token still finds the right position — the
wrapper's prefix wraps the entire smolvm-exec framing.
Tests:
- `test_smolmachines_pty_resize.py` (new): argv parsing, the
side-channel command shape (cols/rows / for-loop over
/dev/pts/*), and `_read_winsize`'s fallback across
stdin/stdout/stderr including the smolvm-allocated-PTY-
reports-`0 0` ironic case.
- `test_smolmachines_bottle.py`: updated TTY-mode assertions
to unwrap the pty_resize prefix; added `TestClaudeArgvNoTTY`
to lock the non-TTY skip.
636 unit tests pass.
Removable when smolvm grows native SIGWINCH forwarding.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Launching a smolmachines agent from the dashboard inside tmux
crashed with
AttributeError: 'SmolmachinesBottle' object has no attribute
'claude_docker_argv'
because the tmux pane-respawn path called
`bottle.claude_docker_argv(...)` directly — a method that only
existed on DockerBottle. The foreground-handoff path (curses
endwin → subprocess.run → restore) doesn't hit it; it goes
through `bottle.exec_claude` which is on the ABC.
- Move the argv builder onto the `Bottle` ABC as
`claude_argv(argv, *, tty=True) -> list[str]`. Both backends
implement it; both `exec_claude` impls collapse to
`subprocess.run(self.claude_argv(argv, tty=tty), check=False)`.
- DockerBottle: rename `claude_docker_argv` → `claude_argv`,
body unchanged.
- SmolmachinesBottle: extract the argv-building from
`exec_claude` into `claude_argv`; the new method returns the
full `smolvm machine exec --name … -- runuser -u node --
claude …` argv. The `runuser` switch lives on the
exec-framing prefix so the dashboard's
`_build_resume_argv_with_fallback` split-at-"claude" trick
keeps the UID switch when wrapping the claude tail in
`sh -c "… --continue || …"`.
- Dashboard: drop the docker-specific wording — local + helper
arg names `docker_argv` → `claude_argv`; docstrings on
`_build_resume_argv_with_fallback`, `_build_split_pane_argv`,
`_build_respawn_pane_argv` now say "backend-exec argv". The
shell-fallback wrap is unchanged; the existing logic works
for smolmachines because `claude` is still the marker token.
Tests:
- `tests/unit/test_smolmachines_bottle.py` (new): locks down
the smolmachines argv shape — prompt-file flag injection,
guest-env `-e K=V` forwarding, TTY toggle, runuser-precedes-
claude invariant.
- `test_docker_bottle.py`: TestClaudeDockerArgv →
TestClaudeArgv; method renames follow.
- `test_dashboard_active_agents.py`: docstring follow.
615 unit tests pass.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
didericis-claude