You expanded the descriptions of get_customer and lookup_order with input formats, example queries, and boundaries. Selection improved, but for billing disputes about a specific order the agent still calls get_customer repeatedly and rarely calls lookup_order. The system prompt contains the line: "Whenever a customer mentions a charge or a payment, review their account first." What should you do next?

Answer: D — Revise that system prompt line: its keyword-triggered instruction steers the agent toward get_customer and overrides the improved descriptions, so state what to look up rather than reacting to keywords.

System prompt wording can create unintended tool associations, and a keyword-triggered instruction can override well-written tool descriptions, so reviewing the prompt for this is part of tool-interface design (task 2.1). Piling on more description text (a) fights the prompt instead of removing the conflicting instruction. Forcing lookup_order on every first turn (b) breaks conversations that genuinely start with identity verification or account issues. A keyword router (c) is an over-engineered layer that bypasses the model's understanding and repeats the same keyword brittleness in code.