Tool Design & MCP Integration (D2)

A customer support agent has two tools: lookup_order_by_id and lookup_order_by_email. Both descriptions say only 'Looks up an order.' The agent frequently calls the wrong tool, passing an email to lookup_order_by_id. What description change most directly fixes the routing failure?

1. AAdd the accepted input type to each description: lookup_order_by_id accepts a numeric order ID; lookup_order_by_email accepts a customer email address
2. BRename the tools to make the input type obvious: id_lookup and email_lookup
3. CMerge the two tools into one lookup_order tool that accepts either an ID or email and routes internally
4. DAdd a system prompt rule stating the agent must read tool descriptions carefully before selecting a tool