Symfony MCP SDK provides a single example tool ('Current time') with complete schema, clear description, and proper interface implementation. The tool demonstrates good structure with MetadataInterface and ToolExecutorInterface separation. However, the server is primarily an SDK/framework rather than a production MCP server with multiple tools. The single example tool is well-implemented but limited in scope. Tool names are action-oriented but lack the context of a multi-tool system. No evidence of batch operations, pagination patterns, or complex composition scenarios typical of production-grade servers. Error handling is minimal, ToolCallResult.php shows basic structure but lacks recovery guidance. Output schema is not documented (getOutputSchema() returns null), violating the documented output pattern.

• Define and return a structured output schema from getOutputSchema(). E.g. {"type": "object", "properties": {"timestamp": {"type": "string", "description": "ISO 8601 formatted UTC timestamp"}, "format_used": {"type": "string"}}}
• Add enum constraint to 'format' parameter with valid PHP date format codes (Y-m-d, Y-m-d H:i:s, etc.) rather than open-ended string. Prevents invalid format strings.
• Implement getAnnotations() to return a ToolAnnotationsInterface with readOnlyHint=true, idempotentHint=true, destructiveHint=false. Helps LLM understand tool is safe to retry.
• Add error description to tool definition: 'Returns invalid format error if the format string contains unsupported directives. Valid formats: Y-m-d H:i:s, Y-m-d, H:i:s, etc.'
• Include full example in tool description: 'Returns the current UTC time in the specified PHP date format. Example: format="Y-m-d H:i:s" returns "2025-07-28 14:32:15". Defaults to Y-m-d H:i:s.'
• Create additional example tools (e.g., get_user, create_task, list_tasks) in the examples directory to demonstrate composition, pagination, batch operations, and error handling patterns.

Inferred effective spec: 2025-06-18+.

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