A node with no `shape` defaulted to `box`, which resolves to the agent
handler. That made a shapeless `script` node run as an LLM call prompted
with its own label, while the `script` was reported as inert — wrong
behavior behind a warning.
`script` is read by the command handler and by nothing else, so a
shapeless node that sets it is unambiguously a command node. `shape()`
now infers `parallelogram` in that case. An explicit `shape` still wins.
Two rules keep the inference honest:
- `script_prompt_conflict` — setting both `script` and `prompt` is an
error. No handler reads both. It fires regardless of shape so that
adding one cannot downgrade the error to a warning.
- `command_requires_script` — a command node without a script is an
error. Without this the original trap just moves: a node meant as a
command that omits its script silently becomes an agent again.
Also drops the `tool_command` alias in favor of `script` alone, routing
the six read sites through a new `Node::script()` accessor.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
