{"passport":{"unfragile":{"@version":"1.0","version":"2026-05","artifact":{"id":"npm_npm-modelcontextprotocolclient","slug":"npm-modelcontextprotocolclient","name":"@modelcontextprotocol/client","type":"mcp","url":"https://www.npmjs.com/package/@modelcontextprotocol/client","page_url":"https://unfragile.ai/npm-modelcontextprotocolclient","categories":["mcp-servers"],"tags":["modelcontextprotocol","mcp","client"],"pricing":{"model":"open_source","free":true,"starting_price":null},"status":"active","verified":false},"capabilities":[{"id":"npm_npm-modelcontextprotocolclient__cap_0","uri":"capability://tool.use.integration.bidirectional.mcp.client.server.transport","name":"bidirectional-mcp-client-server-transport","description":"Establishes and manages bidirectional message transport between MCP clients and servers using JSON-RPC 2.0 protocol over stdio, HTTP, or custom transports. Implements automatic message serialization/deserialization, request-response correlation via message IDs, and error handling with typed error responses. Handles both synchronous request-response patterns and asynchronous server-initiated notifications through a unified message queue and event dispatcher.","intents":["Connect an LLM application to remote tools and data sources via standardized MCP protocol","Build a client that can discover and invoke capabilities exposed by MCP servers","Handle bidirectional communication where servers can push notifications back to clients","Manage connection lifecycle including initialization, capability negotiation, and graceful shutdown"],"best_for":["TypeScript/JavaScript developers building LLM agents and assistants","Teams integrating multiple tool providers through a unified protocol","Developers migrating from custom RPC systems to standardized MCP"],"limitations":["TypeScript/JavaScript only — no native Python, Go, or Rust bindings","Stdio transport requires subprocess management; HTTP transport adds network latency","Message ordering guarantees only within a single connection; distributed scenarios require external coordination","No built-in message persistence or replay — connection loss requires client-side recovery logic"],"requires":["Node.js 16+ (for async/await and modern ES features)","TypeScript 4.5+ or JavaScript ES2020+","MCP server implementing compatible JSON-RPC 2.0 protocol","For stdio transport: ability to spawn child processes"],"input_types":["JSON-RPC 2.0 request objects","Tool/resource definitions from server capabilities","Structured arguments matching server-defined schemas"],"output_types":["JSON-RPC 2.0 response objects","Typed tool results","Server notifications and events","Capability metadata (tools, resources, prompts)"],"categories":["tool-use-integration","automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_1","uri":"capability://tool.use.integration.tool.invocation.with.schema.validation","name":"tool-invocation-with-schema-validation","description":"Provides typed tool calling with automatic JSON schema validation, parameter marshaling, and result handling. Client maintains a registry of available tools discovered from the server during initialization, validates incoming tool calls against their declared schemas, and routes execution to the appropriate handler. Supports both synchronous and asynchronous tool implementations with error propagation back to the LLM.","intents":["Safely invoke remote tools with automatic parameter validation before execution","Discover what tools a server exposes and their required/optional parameters","Handle tool execution errors and return structured error responses to the LLM","Implement custom tool handlers that wrap external APIs or business logic"],"best_for":["LLM application developers building agentic systems with external tool access","Teams standardizing tool interfaces across multiple backend services","Developers who want schema-driven tool integration without manual validation code"],"limitations":["Schema validation is JSON Schema only — no support for OpenAPI 3.0 or other schema formats","Tool execution is synchronous from the client perspective; long-running tools block the message loop unless wrapped in async handlers","No built-in rate limiting, retry logic, or circuit breakers for tool calls","Tool results must be JSON-serializable; binary data requires base64 encoding"],"requires":["Node.js 16+","MCP server that exposes tools via the tools/list and tools/call endpoints","JSON Schema validator (typically ajv or similar, bundled in client)"],"input_types":["Tool call requests with name and arguments","JSON-serializable argument values","Tool definitions with JSON Schema"],"output_types":["Tool execution results (JSON)","Tool error responses with error codes and messages","Tool metadata (name, description, schema)"],"categories":["tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_10","uri":"capability://code.generation.editing.type.safe.capability.registries","name":"type-safe-capability-registries","description":"Builds and maintains typed registries for tools, resources, and prompts discovered from the server, enabling type-safe access and validation. Each registry entry includes metadata (name, description, schema), and the client provides typed methods to look up and invoke capabilities. TypeScript types are generated from server-provided schemas, enabling IDE autocomplete and compile-time type checking.","intents":["Access tools, resources, and prompts with full type safety and IDE autocomplete","Validate capability names and arguments at compile time","Inspect capability metadata programmatically","Generate TypeScript types from server schemas"],"best_for":["TypeScript developers who want compile-time safety for MCP integrations","Teams building type-safe LLM applications","Developers using IDEs with strong TypeScript support"],"limitations":["Type generation requires TypeScript 4.5+; no runtime type checking in JavaScript","Schema-to-type conversion is limited to JSON Schema; complex schemas may not map cleanly to TypeScript types","Types are generated at build time; runtime schema changes require rebuild","No support for discriminated unions or complex type patterns"],"requires":["TypeScript 4.5+","TypeScript compiler or build tool","JSON Schema from server capabilities"],"input_types":["Server capability definitions (tools, resources, prompts)","JSON Schema for capability arguments"],"output_types":["TypeScript type definitions","Typed registry objects","IDE autocomplete suggestions"],"categories":["code-generation-editing","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_11","uri":"capability://automation.workflow.request.response.promise.based.api","name":"request-response-promise-based-api","description":"Provides a promise-based API for making requests to the server, with automatic message ID generation, request tracking, and response correlation. Each request returns a promise that resolves with the response or rejects with an error. Supports timeout handling and cancellation via AbortController.","intents":["Make requests to the server with async/await syntax","Handle request timeouts and cancellation","Track pending requests and their status","Implement request-response patterns without callback hell"],"best_for":["JavaScript/TypeScript developers familiar with promises and async/await","Applications that need clean, readable request handling","Teams using modern async patterns"],"limitations":["Promises are not cancellable natively; AbortController support depends on implementation","No built-in request queuing or rate limiting","Timeout handling is per-request; no global timeout configuration","Promise rejection loses stack context; error handling requires careful try-catch placement"],"requires":["Node.js 16+ (for Promise and async/await support)","Understanding of promise-based APIs"],"input_types":["Request method name","Request parameters","Timeout value (optional)","AbortSignal (optional)"],"output_types":["Promise resolving to response object","Promise rejecting with error object"],"categories":["automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_2","uri":"capability://memory.knowledge.resource.access.with.uri.templates","name":"resource-access-with-uri-templates","description":"Manages access to server-exposed resources (files, documents, database records) through URI-based addressing with template expansion. Client maintains a resource list from the server, resolves URI templates with provided arguments, and fetches resource contents with automatic caching and refresh semantics. Supports both read-only resource access and resource listing with filtering.","intents":["Access documents, files, or data records from a server using standardized URI syntax","List available resources and their metadata without loading full contents","Provide LLM with context from external data sources without embedding everything in the prompt","Implement resource-aware prompting where tool calls can reference specific resources"],"best_for":["Developers building RAG-adjacent systems where resources are managed by external servers","Teams with document management or knowledge base systems that need LLM integration","Applications where resource access patterns are dynamic and server-managed"],"limitations":["No built-in caching strategy — resources are fetched on-demand; no TTL or invalidation semantics","URI templates use simple variable substitution; no support for complex path expressions or query parameters","Resource contents must be text-based (UTF-8); binary resources require base64 encoding","No pagination support for large resource lists — server must handle filtering"],"requires":["Node.js 16+","MCP server implementing the resources/list and resources/read endpoints","URI template strings matching RFC 6570 (simple variable substitution)"],"input_types":["Resource URIs with template variables","Resource list filter parameters","Resource metadata queries"],"output_types":["Resource contents (text/UTF-8)","Resource metadata (name, description, MIME type, URI template)","Resource list with pagination tokens"],"categories":["memory-knowledge","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_3","uri":"capability://text.generation.language.prompt.template.management.and.composition","name":"prompt-template-management-and-composition","description":"Manages reusable prompt templates exposed by the server, with support for argument substitution, composition, and versioning. Client discovers available prompts during initialization, renders them with provided arguments, and can chain multiple prompts together. Supports both simple string templates and complex prompts with embedded tool calls and resource references.","intents":["Reuse standardized prompts across multiple LLM invocations without duplicating prompt engineering","Compose complex prompts from server-managed templates with dynamic argument injection","Version and update prompts server-side without changing client code","Implement prompt patterns that reference tools and resources available in the same MCP context"],"best_for":["Teams with shared prompt libraries that need to be versioned and updated centrally","LLM applications where prompt consistency across multiple agents is critical","Developers building prompt-as-code systems with server-side management"],"limitations":["Prompt templates are server-managed; no client-side template caching or offline rendering","Template syntax is server-defined; no standardized template language (Jinja2, Handlebars, etc.)","No built-in prompt validation or testing framework","Argument substitution is simple string replacement; no support for conditional logic or loops"],"requires":["Node.js 16+","MCP server implementing the prompts/list and prompts/get endpoints","Server-defined template format and argument schema"],"input_types":["Prompt names and argument objects","Prompt metadata queries"],"output_types":["Rendered prompt text","Prompt metadata (name, description, arguments, tools, resources)","Prompt list with filtering"],"categories":["text-generation-language","memory-knowledge"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_4","uri":"capability://tool.use.integration.capability.discovery.and.initialization","name":"capability-discovery-and-initialization","description":"Implements the MCP initialization handshake that discovers server capabilities (tools, resources, prompts) and negotiates protocol version and features. Client sends an initialize request with its own capabilities, receives the server's capability list, and builds internal registries for tools, resources, and prompts. Handles version negotiation and feature flags to ensure compatibility.","intents":["Discover what capabilities a server exposes before attempting to use them","Negotiate protocol version and optional features with the server","Validate server capabilities match client expectations","Handle servers with different capability sets gracefully"],"best_for":["Developers building flexible MCP clients that work with heterogeneous servers","Teams implementing MCP servers and needing to understand the initialization protocol","Applications that need to adapt behavior based on available server capabilities"],"limitations":["Initialization is synchronous and blocking; no lazy loading of capabilities","Capability changes on the server side require reconnection to refresh","No support for capability versioning or deprecation warnings","Server capabilities are discovered once at init time; dynamic capability changes are not supported"],"requires":["Node.js 16+","MCP server implementing the initialize endpoint","Protocol version compatibility (typically MCP 1.0)"],"input_types":["Client name and version","Client capability declarations"],"output_types":["Server name and version","Server capabilities (tools, resources, prompts)","Protocol version and feature flags","Server metadata"],"categories":["tool-use-integration","automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_5","uri":"capability://automation.workflow.stdio.transport.with.subprocess.management","name":"stdio-transport-with-subprocess-management","description":"Manages stdio-based transport for MCP servers running as local subprocesses. Spawns server processes, handles stdin/stdout communication with line-buffered JSON message exchange, manages process lifecycle (startup, shutdown, restart), and provides error handling for process crashes. Implements automatic reconnection and graceful shutdown with timeout handling.","intents":["Connect to MCP servers running as local command-line tools or scripts","Manage subprocess lifecycle without manual process handling","Handle server crashes and implement automatic reconnection","Debug communication by inspecting raw JSON messages"],"best_for":["Developers integrating local tools and scripts via MCP","Teams running MCP servers in containerized environments","Applications that need tight coupling with server processes"],"limitations":["Stdio transport is local-only; no network communication","Process spawning requires appropriate permissions and environment setup","Line-buffered JSON parsing can fail if server outputs non-JSON text to stdout","No built-in process resource limits or memory management","Reconnection logic is basic; no exponential backoff or jitter"],"requires":["Node.js 16+","Ability to spawn child processes (not available in browser/serverless)","MCP server executable or script with proper shebang/interpreter"],"input_types":["Server command and arguments","Environment variables","Stdin messages (JSON-RPC)"],"output_types":["Stdout messages (JSON-RPC)","Process exit codes and error messages","Server logs (if redirected)"],"categories":["automation-workflow","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_6","uri":"capability://automation.workflow.http.transport.with.request.response.correlation","name":"http-transport-with-request-response-correlation","description":"Implements HTTP-based transport for MCP servers accessible via HTTP endpoints. Sends JSON-RPC requests as HTTP POST bodies, correlates responses via message IDs, and handles HTTP-specific concerns like timeouts, retries, and connection pooling. Supports both request-response patterns and server-sent events (SSE) for server-initiated notifications.","intents":["Connect to MCP servers exposed via HTTP APIs","Integrate with cloud-hosted or remote MCP servers","Handle network failures and timeouts gracefully","Support server-initiated notifications via SSE or polling"],"best_for":["Developers integrating remote MCP servers over the network","Cloud-native applications using HTTP-based service communication","Teams with existing HTTP infrastructure for MCP"],"limitations":["HTTP adds network latency compared to stdio; typical round-trip is 50-500ms","No built-in request batching; each message is a separate HTTP request","SSE support for notifications requires server implementation; polling is inefficient","No built-in authentication beyond HTTP headers; OAuth/mTLS requires custom setup","Connection pooling and keep-alive must be configured at the HTTP client level"],"requires":["Node.js 16+","HTTP client library (typically node-fetch or axios, bundled)","MCP server accessible via HTTP with JSON-RPC endpoint","Network connectivity to server"],"input_types":["Server URL","HTTP headers (authentication, custom headers)","JSON-RPC request bodies"],"output_types":["HTTP response bodies (JSON-RPC)","HTTP status codes and error messages","SSE events (if supported)"],"categories":["automation-workflow","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_7","uri":"capability://safety.moderation.error.handling.with.typed.error.responses","name":"error-handling-with-typed-error-responses","description":"Implements comprehensive error handling with typed error responses following JSON-RPC 2.0 error specification. Distinguishes between protocol errors (invalid requests, parse errors), server errors (tool execution failures, resource not found), and transport errors (connection failures, timeouts). Provides structured error objects with error codes, messages, and optional error data for programmatic handling.","intents":["Handle tool execution failures and return meaningful error messages to the LLM","Distinguish between different error types (protocol, server, transport) for appropriate recovery","Implement error recovery logic based on error codes","Debug integration issues by inspecting detailed error information"],"best_for":["Developers building robust LLM agents that need to handle failures gracefully","Teams implementing error recovery and retry logic","Applications that need to provide meaningful error messages to users"],"limitations":["Error codes are limited to JSON-RPC standard codes; custom error codes require error data field","Error messages are server-generated; no client-side error message localization","No built-in retry logic; applications must implement their own","Stack traces are not included in error responses for security reasons"],"requires":["Node.js 16+","Understanding of JSON-RPC 2.0 error specification"],"input_types":["JSON-RPC error responses","HTTP error responses","Transport errors (connection failures, timeouts)"],"output_types":["Typed error objects with code, message, and data","Error recovery recommendations","Detailed error context for debugging"],"categories":["safety-moderation","automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_8","uri":"capability://automation.workflow.message.queue.and.event.dispatching","name":"message-queue-and-event-dispatching","description":"Manages an internal message queue for incoming messages and dispatches them to appropriate handlers based on message type (request, response, notification). Implements request-response correlation via message IDs, ensuring responses are routed to the correct pending requests. Provides event emitters for notifications and server-initiated messages, enabling event-driven application logic.","intents":["Handle asynchronous messages from the server without blocking the client","Correlate responses to requests even when messages arrive out of order","Implement event-driven logic that reacts to server notifications","Debug message flow by inspecting the message queue"],"best_for":["Developers building event-driven LLM applications","Teams implementing complex message handling logic","Applications that need to handle out-of-order message delivery"],"limitations":["Message queue is in-memory; no persistence across restarts","Queue size is unbounded; no backpressure handling for slow consumers","Event dispatching is synchronous; slow event handlers block the message loop","No message ordering guarantees across multiple connections"],"requires":["Node.js 16+","Understanding of event-driven programming patterns"],"input_types":["JSON-RPC messages (requests, responses, notifications)","Message IDs for correlation"],"output_types":["Dispatched messages to handlers","Event emissions for notifications","Response promises for pending requests"],"categories":["automation-workflow","planning-reasoning"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"npm_npm-modelcontextprotocolclient__cap_9","uri":"capability://automation.workflow.connection.lifecycle.management","name":"connection-lifecycle-management","description":"Manages the full connection lifecycle including initialization, capability negotiation, active communication, and graceful shutdown. Implements connection state tracking (connecting, connected, disconnected), timeout handling for initialization and requests, and cleanup of resources on disconnect. Provides hooks for connection state changes to enable application-level logic.","intents":["Track connection state and know when the server is ready for use","Implement timeout handling for initialization and long-running requests","Clean up resources properly on disconnect","React to connection state changes in application logic"],"best_for":["Developers building long-lived LLM applications that maintain persistent connections","Teams implementing connection pooling or failover logic","Applications that need to handle connection failures gracefully"],"limitations":["Connection state is local to the client; no distributed state management","Timeout values are fixed; no adaptive timeout adjustment based on latency","No built-in connection pooling or load balancing","Graceful shutdown requires explicit close() call; no automatic cleanup on process exit"],"requires":["Node.js 16+","Understanding of connection state machines"],"input_types":["Connection configuration (server URL, command, etc.)","Timeout values","Connection state change events"],"output_types":["Connection state (connecting, connected, disconnected)","Connection status events","Initialization completion signals"],"categories":["automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0}],"trust":{"score":30,"verified":false,"data_access_risk":"high","permissions":["Node.js 16+ (for async/await and modern ES features)","TypeScript 4.5+ or JavaScript ES2020+","MCP server implementing compatible JSON-RPC 2.0 protocol","For stdio transport: ability to spawn child processes","Node.js 16+","MCP server that exposes tools via the tools/list and tools/call endpoints","JSON Schema validator (typically ajv or similar, bundled in client)","TypeScript 4.5+","TypeScript compiler or build tool","JSON Schema from server capabilities"],"failure_modes":["TypeScript/JavaScript only — no native Python, Go, or Rust bindings","Stdio transport requires subprocess management; HTTP transport adds network latency","Message ordering guarantees only within a single connection; distributed scenarios require external coordination","No built-in message persistence or replay — connection loss requires client-side recovery logic","Schema validation is JSON Schema only — no support for OpenAPI 3.0 or other schema formats","Tool execution is synchronous from the client perspective; long-running tools block the message loop unless wrapped in async handlers","No built-in rate limiting, retry logic, or circuit breakers for tool calls","Tool results must be JSON-serializable; binary data requires base64 encoding","Type generation requires TypeScript 4.5+; no runtime type checking in JavaScript","Schema-to-type conversion is limited to JSON Schema; complex schemas may not map cleanly to TypeScript types","builder identity is not verified yet","no observed match outcomes yet"],"rank_breakdown":{"adoption":0.05,"quality":0.34,"ecosystem":0.38999999999999996,"match_graph":0.25,"freshness":0.75,"weights":{"adoption":0.25,"quality":0.25,"ecosystem":0.15,"match_graph":0.23,"freshness":0.12}},"observed_outcomes":{"matches":0,"success_rate":0,"avg_confidence":0,"top_intents":[],"last_matched_at":null},"maintenance":{"status":"active","updated_at":"2026-05-24T12:16:23.904Z","last_scraped_at":"2026-05-03T14:23:41.656Z","last_commit":null},"community":{"stars":null,"forks":null,"weekly_downloads":null,"model_downloads":null,"model_likes":null}},"distribution":{"claim_url":"https://unfragile.ai/submit?claim=npm-modelcontextprotocolclient","compare_url":"https://unfragile.ai/compare?artifact=npm-modelcontextprotocolclient"}},"signature":"gQFS9oNDq0XTXlr2Fwyr1xazX/pJZDMfy6SBwSgtE5Ahgt+jDuOuGqXKbdBudu4W8OiEPXd+FchVte/1Bfh/CQ==","signedAt":"2026-06-21T04:45:12.243Z","signedBy":"unfragile.ai","version":1},"_links":{"self":"https://unfragile.ai/api/v1/passport/npm-modelcontextprotocolclient","artifact":"https://unfragile.ai/npm-modelcontextprotocolclient","verify":"https://unfragile.ai/api/v1/verify?slug=npm-modelcontextprotocolclient","publicKey":"https://unfragile.ai/api/v1/trust-passport-public-key","spec":"https://unfragile.ai/trust","schema":"https://unfragile.ai/schema.json","docs":"https://unfragile.ai/docs"}}