apc-mcp demonstrates solid tool design with complete schemas, clear descriptions, and proper error handling. All 6 tools have explicit registrations with Zod schemas and descriptions. Naming follows verb_noun convention (book_, get_, track_, cancel_, list_). Descriptions average ~180 chars, within the 10-1024 baseline. Parameters are well-typed with enums for constrained inputs (itemType, format, service). However, output schemas are not formally documented, responses are JSON stringified without explicit schema declarations. Address objects are reused effectively via addressSchema. Error handling returns isError flags and actionable messages. Minor gaps: no tool annotations (readOnlyHint/destructiveHint), no pagination support for list_services, and no confirmation pattern for destructive cancel_shipment.

• Document output schemas explicitly. Define return type for each tool (e.g. book_shipment returns {success: boolean, waybill: string, orderNumber: string, ...}). Include this in tool descriptions or as a separate schema field.
• Add tool annotations via server.tool() options: destructiveHint for book_shipment/cancel_shipment, readOnlyHint for get_label/track_shipment/list_services. Helps LLMs reason about safety.
• Implement confirmation pattern for cancel_shipment. Return a confirmation token on first call; require it on second call to actually cancel. Prevents accidental reversals.
• Add pagination to list_services: accept limit (default 20, max 100) and offset/cursor parameters. Return total count and next_cursor. Scales gracefully if service catalogue grows.
• Consider splitting book_batch_and_label into book_batch (returns waybills) and merge_labels (takes waybills, returns merged PDF). Allows agents to book, then label separately if needed.