The prompt operation sends a textual prompt to a configured language model
and returns the resulting textual completion. It is the core mechanism by which
Gendo pipelines interact with local or external language models. This operation
enables integration of natural-language generation and inference directly
within automated pipeline execution.
The syntax of the prompt operation is defined as follows:
[ $destination ] prompt [ prompt-text ]
The $destination identifier is optional. If omitted, the model’s response is
implicitly bound to the special slot _. The prompt-text argument is also
optional. If provided, it explicitly specifies the prompt text sent to the
language model. When prompt-text is omitted, the current value of _ (which
must be a textual value) is used as the prompt implicitly. It is invalid to
omit both $destination and prompt-text, as the operation would have no
explicit action.
An example of a typical prompt invocation using both destination and explicit
prompt-text is:
$summary prompt “Summarize the text above in a single sentence.”
This sends the provided prompt text to the language model and binds the
response directly to the identifier summary.
A simpler example, implicitly using the current value of _ as the prompt and
binding the response implicitly back to _, is as follows:
prompt
In this example, the current textual value of _ is sent to the language
model, and the model’s response replaces the current value of _.
Using prompt with only the destination identifier explicitly defined looks
like this:
$assistant-response prompt
Here, the current value of _ is used implicitly as the prompt, and the
response from the model is bound explicitly to the identifier
assistant-response.
All identifiers bound using prompt follow the single-assignment rule, meaning
each identifier may only be assigned once within the pipeline. Rebinding an
identifier results in an error.
The prompt operation itself does not modify its input text or perform side
effects beyond invoking the configured language model. It returns the model’s
completion verbatim. This makes the operation predictable, deterministic (given
identical inputs and a deterministic model), and suitable for reproducible
pipelines.