{"id":"mcpcat-webmcp-react","name":"webmcp-react","homepage":null,"repo_url":"https://github.com/MCPCat/webmcp-react","category":"ai-ml","subcategories":[],"tags":["react","typescript","webmcp","mcp","navigator-modelcontext","hooks","zod","json-schema","ssr-safe","experimental"],"what_it_does":"Provides React hooks/components (<WebMCPProvider>, useMcpTool) that expose typed tools to WebMCP via navigator.modelContext in a transport-agnostic, SSR-safe way. It uses Zod-first tool input definitions with optional JSON Schema fallback, and includes a polyfill for environments without native WebMCP. Tools can dynamically register/unregister with React lifecycle and supports annotations and execution state via the hook.","use_cases":["Exposing app functionality as typed WebMCP tools from a browser app","Building agent-aware UI where tools appear/disappear based on app state (React mount/unmount)","SSR-capable Next.js/Remix apps that still need WebMCP tool exposure","Providing hinting/metadata to AI agents via MCP tool annotations","Creating demos/playgrounds and developer tooling (e.g., dev panels to inspect tool state)"],"not_for":["Server-side-only use cases that cannot run in the browser","Replacing a backend/authorization layer for sensitive operations (it does not provide authentication/authorization by itself)","Production-grade solutions that require stable Web standard guarantees (WebMCP is described as experimental)","Use cases that need REST/GraphQL/gRPC APIs or webhooks for tool invocation"],"best_when":"When you want to expose typed, client-side tool functions to WebMCP-compatible agents (often via the WebMCP Bridge extension) and you value React lifecycle integration and input validation via Zod.","avoid_when":"When your environment cannot use navigator.modelContext (and you cannot rely on the polyfill/bridge), or when you need strong auth/rate limiting/security controls at the tool layer.","alternatives":["Implement WebMCP tool exposure directly without React hooks","Use another MCP/WebMCP client/server library depending on your architecture (e.g., MCP server-side tool runners)","Build a backend API (REST/GraphQL) and expose it to agents via a dedicated connector rather than navigator.modelContext"],"af_score":54.0,"security_score":49.2,"reliability_score":28.8,"package_type":"mcp_server","discovery_source":["github"],"priority":"high","status":"evaluated","version_evaluated":null,"last_evaluated":"2026-03-30T15:35:26.550556+00:00","interface":{"has_rest_api":false,"has_graphql":false,"has_grpc":false,"has_mcp_server":false,"mcp_server_url":null,"has_sdk":true,"sdk_languages":["TypeScript","JavaScript"],"openapi_spec_url":null,"webhooks":false},"auth":{"methods":[],"oauth":false,"scopes":false,"notes":"No authentication mechanism is described for the library itself. Authorization for tool handlers would be up to the application code (e.g., guarding handlers based on user/session context)."},"pricing":{"model":null,"free_tier_exists":false,"free_tier_limits":null,"paid_tiers":[],"requires_credit_card":false,"estimated_workload_costs":null,"notes":"Open-source library (MIT per README badges/license references). Pricing for usage is not applicable beyond your app/hosting costs."},"requirements":{"requires_signup":false,"requires_credit_card":false,"domain_verification":false,"data_residency":[],"compliance":[],"min_contract":null},"agent_readiness":{"af_score":54.0,"security_score":49.2,"reliability_score":28.8,"mcp_server_quality":0.0,"documentation_accuracy":80.0,"error_message_quality":0.0,"error_message_notes":null,"auth_complexity":90.0,"rate_limit_clarity":0.0,"tls_enforcement":100.0,"auth_strength":20.0,"scope_granularity":10.0,"dependency_hygiene":55.0,"secret_handling":70.0,"security_notes":"No authentication/authorization or scope model is provided by the library (handlers run in your app context). Treat tool handlers as sensitive and enforce user permissions server-side or via secure client context. The library includes a polyfill/bridge scenario; ensure that tool registration does not expose privileged actions to unauthorized agents/users. Rate limiting and abuse prevention are not mentioned in the provided materials.","uptime_documented":0.0,"version_stability":35.0,"breaking_changes_history":30.0,"error_recovery":50.0,"idempotency_support":"false","idempotency_notes":"The README mentions an idempotentHint annotation, but does not document automatic idempotency/retry behavior in the library itself.","pagination_style":"none","retry_guidance_documented":false,"known_agent_gotchas":["WebMCP is described as experimental; browser support and behavior may change.","Desktop MCP clients typically require the WebMCP Bridge extension to reach navigator.modelContext.","Tools register/unregister with React mount/unmount; agents may need to handle tools appearing/disappearing as UI state changes.","No library-level authentication/authorization is provided; ensure handlers enforce permissions."]}}