Tool Selection Policies: When to Call Tools vs Think
Tool Selection Policies: When to Call Tools vs Think
The hidden cost of tool calls
Tool calls cost money, time, and complexity. A mature agent has a tool policy: call tools only when the expected value is higher than thinking.
A simple decision rule
- If the question requires fresh facts → use tools
- If the answer is pure reasoning → think
- If the risk is high (finance, legal, medical) → verify with tools
Tool confidence thresholds
Let the agent estimate uncertainty. If uncertainty is high, fetch evidence. If low, answer directly.
Preventing hallucinated tool outputs
Tool outputs should be machine-readable (JSON) and the agent should quote from observations, not invent results.
Budget-aware policies
Stop calling tools when the budget is nearly exhausted. Provide the best-effort answer and clearly state what could not be verified.
