KiasuMiles demonstrates solid tool design with clear action verbs, comprehensive parameter schemas, and domain-specific descriptions. All 7 tools have explicit descriptions (avg 156 chars) and well-typed input schemas. However, output schemas are not documented in the source, parameter descriptions lack constraint details (ranges, enums, formats), and error handling guidance is absent. The hosted-only tools (lookup_hosted, compare_payment_methods) are well-scoped for agent composition. Tool naming follows verb_noun convention consistently. Missing: output schema documentation, enum constraints for categorical parameters (channel, category), and recovery guidance in error cases.

• Document output schemas for all tools. Example: 'Returns {cards: [{card_id: string, card_name: string, bank: string, ...}], total: number}'. LLMs need this to chain tools.
• Add enum constraints to categorical parameters. Define channel as enum: [mobile_contactless, contactless, online] and category as enum: [dining, grocery, transport, petrol, pharmacy, hotel, airlines, shopping].
• Add numeric bounds to parameters. E.g., 'amount_sgd: number (0 - 10000)', 'limit: integer (1 - 100, default 20)', 'top_n: integer (1 - 10, default 3)'.
• Enhance descriptions with recovery hints. E.g., lookup_hosted: 'If merchant not found, try list_cards() to verify card IDs or changes_since() to check recent rule updates.'
• Clarify tool selection criteria. Add to lookup_hosted: 'Use this for single-merchant recommendations.' Add to compare_payment_methods: 'Use this to compare payment methods (mobile vs. contactless vs. online) for the same merchant.'