ser2mcp demonstrates solid definition quality with comprehensive parameter schemas and detailed descriptions across 14 tools. All tools have explicit input schemas with typed parameters and descriptions. Tool names follow verb_noun convention (uart_open, uart_read, uart_write). However, descriptions are verbose (often 200+ chars) and could be more concise for LLM parsing. Output schemas are not formally documented in the visible code. Error handling guidance is minimal, most tools lack recovery hints. Security considerations (file path validation, permission checks) are mentioned in INSTRUCTIONS but not enforced at tool level.

• Add formal JSON Schema output definitions for all tools. Document return fields (data, reason, pending, overflow_delta, new_data_observed, etc.) with types and descriptions so LLMs know what to expect.
• Shorten tool descriptions to 50-150 chars. Move implementation details (idle_ms logic, buffer overflow behavior) into parameter descriptions. Example: 'uart_read' → 'Read buffered serial data, returning when idle, full, or timeout.' Keep INSTRUCTIONS for advanced usage.
• Add error recovery hints to tool descriptions. E.g., uart_open: 'Opens a serial port. If port not found, call uart_list_ports() to see available ports.' uart_expect: 'Waits for a pattern. If timeout, check pattern encoding (hex vs text) and increase timeout_ms.'
• Implement path validation for uart_send_file and uart_send_estimate. Restrict to a configured directory or require explicit user approval. Log file access for audit trails.
• Formalize numeric constraints in JSON Schema (minValue, maxValue, minimum, maximum) rather than text descriptions. E.g., uart_open.baudrate: {type: integer, minimum: 50, maximum: 4000000}.

Inferred effective spec: 2025-06-18+.

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