The Shippo MCP server exposes 9 tools with minimal schema documentation. Tool names follow verb_noun convention (CreateShipment, GetTrack, ValidateAddress, ListShipments, createWebhook, etc.), which is good. However, critical gaps exist: no visible input parameter schemas in the provided source code, descriptions are present but generic (10-50 chars), and no documented output schemas. The server acts as a bridge to a hosted API (mcp.shippo.com), which limits visibility into actual parameter definitions. Without access to the full tool registration code showing JSON Schema definitions, parameter types, and constraints, schema quality cannot be verified. Risk annotations (WRITE, READ_ONLY, DESTRUCTIVE) are present in metadata but not reflected in tool definitions.

• Add explicit JSON Schema definitions for all tool inputs. Include type, description, enum constraints, and min/max for every parameter. Example: { 'type': 'object', 'properties': { 'shipment_id': { 'type': 'string', 'description': 'Unique shipment identifier (e.g., shp_abc123)' } }, 'required': ['shipment_id'] }
• Expand tool descriptions to 80-150 characters. Include WHEN to use (e.g., 'Call this after creating a shipment to fetch available carrier rates'), prerequisites (e.g., 'Requires a valid shipment_id'), and what the tool returns. Example: 'Retrieve tracking updates for a shipped package. Call after purchasing a label. Returns tracking events, estimated delivery, and carrier status.'
• Document output schemas for each tool. Specify response field names, types, and which fields are needed for chaining (e.g., shipment_id, label_id, tracking_number). Include pagination info (limit, offset, total_count) for list tools.
• Standardize naming: choose either PascalCase (CreateShipment, GetTrack) or camelCase (createShipment, getTrack) across all tools. Consistency helps LLMs parse intent from names alone.
• Add error handling guidance. For each tool, document: (1) what errors can occur, (2) whether they are retryable, (3) what the LLM should do next. Example: 'If address validation fails with "invalid_zip", ask the user to confirm the postal code and retry.'