webmcp-react

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.

Evaluated Mar 30, 2026 (22d ago)
Repo ↗ Ai Ml react typescript webmcp mcp navigator-modelcontext hooks zod json-schema ssr-safe experimental
⚙ Agent Friendliness
54
/ 100
Can an agent use this?
🔒 Security
49
/ 100
Is it safe for agents?
⚡ Reliability
29
/ 100
Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality
0
Documentation
80
Error Messages
0
Auth Simplicity
90
Rate Limits
0

🔒 Security

TLS Enforcement
100
Auth Strength
20
Scope Granularity
10
Dep. Hygiene
55
Secret Handling
70

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.

⚡ Reliability

Uptime/SLA
0
Version Stability
35
Breaking Changes
30
Error Recovery
50
AF Security Reliability

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.

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

Interface

REST API
No
GraphQL
No
gRPC
No
MCP Server
No
SDK
Yes
Webhooks
No

Authentication

OAuth: No Scopes: No

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

Free tier: No
Requires CC: No

Open-source library (MIT per README badges/license references). Pricing for usage is not applicable beyond your app/hosting costs.

Agent Metadata

Pagination
none
Idempotent
False
Retry Guidance
Not documented

Known 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.

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Scores are editorial opinions as of 2026-03-30.

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17761
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586
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