• Programming Interface. This kind of interface allows the model to go beyond pure natural language
and specify its action using a program. Such uniﬁcation requires the model to be acquainted with the
syntax of the function calls. The recent code-generating language models (CLM) such as Incoder (Fried
et al., 2022) and CodeX (Chen et al., 2021) provide the possibility of such uniﬁcation. The programming
interface has been applied widely. For example, Code-as-Policies (Liang et al., 2022a) ﬁnds that with
CLM as the backbone for robotic control, the robots can leverage the code grammar to perform complex
actions, generalize to novel instructions, and give precise control with accurate parameter values to the
functions. The programming interface provides promising opportunities for tool learning because (1)
complex tool learning logic can be modeled using the control ﬂow of programming language; (2) explicit
calls of external APIs can be naturally implemented by executing programs.
Tool Learning with Foundation Models