Single tool 'execute_skill_action' has a reasonable name starting with verb, but the implementation is severely deficient. The tool definition exists in mcp_server.py with a schema, but the actual MCP server code is non-functional, it only prints a JSON status message and does not implement the MCP protocol at all. No request/response handling, no tool invocation logic, no error handling. The schema is present with 4 parameters (order_subtotal_usd, origin_country_iso, destination_country_iso, hs_tariff_code), all with type and description. However, the tool description is generic (41 chars) and lacks context on when/why to use it. Parameter descriptions are minimal (e.g., 'ISO country code of origin (e.g., 'US')', includes example value, which violates pattern:tool-description). No output schema documented. The client.py and example_usage.py are mock implementations with hardcoded responses, not integrated with the MCP server. This is a skeleton project, not a working MCP server.

• Implement the MCP protocol in mcp_server.py: parse JSON-RPC requests, dispatch to tool handlers, return structured responses. Use the official MCP Python SDK or implement the spec directly.
• Expand tool description to 100-150 chars: 'Calculate cross-border VAT, customs duties, and landed costs for international orders. Returns tax breakdown, tariff amounts, and DDP compliance status. Call this before finalizing international shipments.'
• Replace example values with enum constraints: origin_country_iso and destination_country_iso should list valid ISO 3166-1 alpha-2 codes (or accept any 2-letter code with validation). hs_tariff_code should specify format (e.g., '8 digits, e.g. 8471.30.01' → pattern: '^\d{4}\.\d{2}\.\d{2}$').
• Document the output schema with all fields: tax_calculation_id (string), origin (string), destination (string), vat_tax_amount_usd (number), customs_import_tariff_duty_usd (number), landed_cost_total_usd (number), ddp_delivery_duty_paid_compliant (boolean), tax_breakdown_dossier_url (string).
• Add error handling: validate ISO codes and HS tariff format; return actionable errors like 'Invalid destination country: DE is not supported. Supported: US, GB, CA, DE, FR, IT, ES' instead of silent failures.