Server has 23 tools across QBO and Divvy integrations. Tool naming follows verb_noun convention (qbo_list_*, qbo_get_*, qbo_create_*, etc.), which is good. However, source code inspection reveals critical gaps: tool descriptions are not visible in the provided code samples, parameter schemas are not shown, and output schemas are undocumented. The tool-logging.ts file shows result serialization and error handling infrastructure, but without seeing actual tool registration (src/tools/*.ts files are not fully provided), schema quality cannot be verified. Based on visible code, descriptions appear to be missing or minimal, and parameter validation rules are not evident. The server implements result-size budgeting and error logging, which is positive, but these are infrastructure concerns, not definition quality.

• Add 50-200 character descriptions to all 23 tools explaining WHAT they do, WHEN to use them, and any prerequisites. Example: 'qbo_list_accounts: Retrieve all accounts from QuickBooks Online. Use this to discover available accounts before creating transactions. Returns account ID, name, type, and balance.'
• Document input schemas with explicit parameter types, descriptions, and constraints. For list tools, add limit (1-100, default 20) and offset/cursor parameters. For write tools, specify required vs optional fields and valid enums.
• Document output schemas for all tools. For list tools, include total_count or next_cursor, and explain which fields are safe to pass to downstream tools (e.g., account_id for qbo_create_purchase).
• Add idempotency support to write tools via idempotency_key parameter. Document in descriptions that repeated calls with the same key are safe and return the same result.
• Enhance error messages with recovery guidance. Instead of 'Error: Invalid account', return 'Invalid account_id. Call qbo_list_accounts to see available accounts, or check the account_id format (must be numeric).'
• Add tool annotations (readOnlyHint, destructiveHint, idempotentHint) to the MCP tool registration for write tools to signal to clients which operations are safe to retry.

Inferred effective spec: 2026-07-28+.

• Relies on Logging (deprecated) - log to stderr or use OpenTelemetry