mcp server implementation with perl async i/o
Enables building MCP (Model Context Protocol) servers in Perl by providing async event-loop integration through Mojolicious's non-blocking I/O framework. Handles JSON-RPC 2.0 message serialization, bidirectional communication over stdio/WebSocket transports, and automatic request routing to handler methods. Uses Mojolicious's Mojo::IOLoop for event-driven request processing without blocking.
Unique: Leverages Mojolicious's battle-tested Mojo::IOLoop event reactor to provide Perl developers with non-blocking MCP server capabilities, avoiding the complexity of raw socket handling while maintaining compatibility with Mojolicious ecosystem patterns (routes, plugins, middleware)
vs alternatives: Provides Perl-native MCP implementation with Mojolicious integration, whereas most MCP SDKs target Python/Node.js and require Perl developers to use language bindings or subprocess wrappers
mcp client request/response handling with protocol validation
Implements MCP client-side protocol handling including JSON-RPC 2.0 message construction, request ID tracking, response correlation, and error handling. Validates incoming messages against MCP schema, manages request timeouts, and provides typed method calls for standard MCP operations (list_resources, call_tool, read_resource). Uses Perl's type system and validation libraries to ensure protocol compliance.
Unique: Provides automatic request ID management and response correlation using Perl's hash-based promise/future pattern, eliminating manual tracking of in-flight requests while maintaining type safety through Mojolicious's validation framework
vs alternatives: Simpler than raw JSON-RPC clients because it abstracts protocol details and provides typed method signatures, whereas generic HTTP/WebSocket clients require developers to manually construct and parse JSON-RPC messages
resource and tool definition with schema-based validation
Provides declarative syntax for defining MCP resources (files, APIs, databases) and tools (callable functions) with JSON Schema validation. Developers define resource metadata (name, description, MIME type, URI template) and tool signatures (parameters, return types) using Perl data structures or builder methods. The SDK automatically generates JSON Schema from Perl type hints and validates incoming requests against these schemas before invoking handlers.
Unique: Integrates with Perl's Type::Tiny ecosystem to generate JSON Schema from native Perl type constraints, enabling developers to define tool signatures once and automatically validate requests, whereas most MCP SDKs require separate schema files or manual validation code
vs alternatives: Reduces boilerplate by deriving schemas from Perl types rather than requiring developers to write and maintain separate JSON Schema files, similar to Python Pydantic but with Perl's type system
transport abstraction layer (stdio, websocket, http)
Abstracts MCP communication over multiple transport protocols through a pluggable transport interface. Supports stdio (for local tool integration), WebSocket (for persistent connections), and HTTP (for request-response patterns). Each transport handles framing, serialization, and connection lifecycle independently. The SDK routes messages through the appropriate transport based on server/client configuration without requiring application code changes.
Unique: Provides unified transport abstraction where developers write server/client code once and switch transports via configuration, using Mojolicious's plugin architecture to load transport handlers dynamically without code changes
vs alternatives: More flexible than SDKs that hardcode a single transport (e.g., Python SDK's stdio-only approach), enabling Perl developers to deploy same MCP implementation across local, remote, and cloud environments
async request handling with perl futures/promises
Enables non-blocking request handling using Perl's Future or Promise libraries integrated with Mojolicious's Mojo::IOLoop event reactor. Tool handlers can return futures that resolve asynchronously, allowing the server to process multiple concurrent requests without blocking. The SDK automatically manages future resolution, error propagation, and timeout handling within the event loop.
Unique: Integrates Perl's Future library with Mojolicious's Mojo::IOLoop to provide async/await-like semantics without requiring Perl 5.32+ async/await syntax, making async MCP servers accessible to developers on older Perl versions
vs alternatives: Enables Perl developers to build concurrent MCP servers comparable to Node.js/Python async servers, whereas naive Perl implementations would block on each request
middleware and plugin system for request/response interception
Provides Mojolicious-style middleware hooks for intercepting and modifying MCP requests and responses before/after handler execution. Developers register middleware that runs in a chain, enabling cross-cutting concerns like logging, authentication, rate limiting, and request transformation. Middleware can short-circuit request processing (e.g., deny unauthorized requests) or modify request/response payloads.
Unique: Reuses Mojolicious's proven middleware architecture (used in production web frameworks) for MCP, providing developers with familiar patterns for request/response interception rather than custom hook systems
vs alternatives: More powerful than simple logging hooks because middleware can modify requests/responses and short-circuit execution, similar to Express.js middleware but adapted for MCP protocol semantics
error handling and exception propagation with mcp error codes
Provides structured error handling that maps Perl exceptions to MCP-compliant error responses with standard error codes (INVALID_REQUEST, METHOD_NOT_FOUND, INVALID_PARAMS, INTERNAL_ERROR, SERVER_ERROR). Developers throw Perl exceptions in tool handlers, and the SDK automatically converts them to JSON-RPC error objects with appropriate codes and messages. Supports custom error codes and error context propagation.
Unique: Automatically maps Perl exceptions to MCP-compliant error codes and messages, eliminating manual error serialization and ensuring all errors follow JSON-RPC 2.0 specification
vs alternatives: More structured than generic exception handlers because it understands MCP error semantics and automatically selects appropriate error codes, whereas raw exception handlers would require developers to manually construct error responses
type coercion and parameter validation for tool arguments
Automatically validates and coerces tool arguments based on JSON Schema definitions before passing to handlers. Converts JSON types to Perl types (strings to numbers, arrays to Perl arrays, objects to hashes), validates constraints (min/max, pattern, enum), and rejects invalid arguments with detailed error messages. Uses JSON Schema validators integrated with Perl type systems.
Unique: Combines JSON Schema validation with Perl type coercion, automatically converting JSON types to Perl equivalents while validating constraints, reducing boilerplate compared to manual validation in each handler
vs alternatives: More comprehensive than simple type checking because it validates constraints (min/max, pattern, enum) and coerces types, whereas basic type guards only check type without validation