Server has 4 tools with complete schemas and descriptions. All tools follow verb_noun naming (lookup_, search_, get_, validate_). Descriptions are adequate (100-200 chars, within baseline 194 avg). However, parameter descriptions lack detail on constraints and formats. Error handling is basic, returns JSON errors but lacks recovery guidance. Output schemas are not documented. No tool annotations (readOnlyHint). Search tool has 6 optional params but no guidance on mutual exclusivity or defaults. CNPJ validation logic is present but not exposed as a constraint in parameter descriptions.

• Add Zod schema constraints: z.string().regex(/^\d{0,14}$/).describe('CNPJ: 14 digits, formatting optional (dots/dashes stripped automatically)'). This makes constraints machine-parseable.
• Document search_companies parameter precedence: 'If multiple filters provided, query takes precedence over name/cnae/uf/municipio. Omit query to use specific filters.'
• Add output schema documentation as JSDoc comments above each tool. Example: '// Returns: { razao_social, cnpj, situacao_cadastral, endereco, ... }' so LLM knows what fields to extract.
• Enhance error messages with recovery hints. E.g., 'CNPJ not found. Verify format (14 digits) or try search_companies() with company name.'
• Add readOnlyHint: true to all tool definitions via server.tool() options to signal safety to LLM and clients.