  Large language models (LLMs) are being applied as actors for sequential
decision making tasks in domains such as robotics and games, utilizing their
general world knowledge and planning abilities. However, previous work does
little to explore what environment state information is provided to LLM actors
via language. Exhaustively describing high-dimensional states can impair
performance and raise inference costs for LLM actors. Previous LLM actors avoid
the issue by relying on hand-engineered, task-specific protocols to determine
which features to communicate about a state and which to leave out. In this
work, we propose Brief Language INputs for DEcision-making Responses (BLINDER),
a method for automatically selecting concise state descriptions by learning a
value function for task-conditioned state descriptions. We evaluate BLINDER on
the challenging video game NetHack and a robotic manipulation task. Our method
improves task success rate, reduces input size and compute costs, and
generalizes between LLM actors.
