Strong tool naming (all verb-first), comprehensive parameter descriptions, and clear destructive/read-only risk annotations. Output schemas are documented in descriptions. However, input schemas lack formal JSON Schema type definitions in the visible code, parameters are described textually but not registered with explicit type/required/enum constraints. Error handling is present but generic. Composition is clean (7 focused tools, no 'and' operations). Missing: formal schema validation, enum constraints for known-value params (e.g., balance types, payment statuses), and structured error recovery guidance.

• Add formal JSON Schema type definitions to all tool inputs. Register each parameter with type (string|number|boolean), required array, and enum constraints where applicable. Example: get_payment_status should declare request_id as required string; get_statement should declare date_from/date_to as required strings with format:date.
• Expose payment status enum as a constraint: status ∈ {WaitingForSign, Allowed, Created, Paid, Rejected, Canceled}. This enables LLM validation before calling get_payment_status.
• Document create_payment parameter interactions explicitly: 'If confirm=true, the payment is created (not dry-run). If dry_run=true, confirm is ignored and a preview is returned. Both cannot be true simultaneously.' Add a note that payer_bik is recommended for the for-sign flow.
• Add error recovery guidance to tool descriptions. Example for get_statement: 'If status is pending, retry with the returned statementId after 30 seconds. If status is error, check date_from/date_to format (YYYY-MM-DD) and account_id validity.'
• Document output schemas formally. For list_accounts, specify: 'Returns array of {accountId: string, currency: string, type: string, status: string}.' For get_account_balance, specify: 'Returns array of {balanceType: string, amount: {amount: number, currency: string}}.' This enables LLMs to plan downstream tool calls.