MCP-Plugin-dotnet

Provides a bridge between MCP clients (via stdio/http) and in-process .NET apps by exposing .NET methods as MCP tools/prompts/resources. The .NET app hosts an in-app SignalR client that connects to a standalone MCP bridge server (McpPlugin.Server), which then serves MCP over stdio/http transports. Tools/prompt/resource schemas are generated from C# types using ReflectorNet, with attribute-based registration and optional fuzzy method matching.

Evaluated Mar 30, 2026 (22d ago)
Repo ↗ DevTools ai mcp dotnet signalr reflection stdio http unity wpf server-client-bridge sdk
⚙ Agent Friendliness
59
/ 100
Can an agent use this?
🔒 Security
48
/ 100
Is it safe for agents?
⚡ Reliability
41
/ 100
Does it work consistently?

Score Breakdown

⚙ Agent Friendliness

MCP Quality
78
Documentation
72
Error Messages
0
Auth Simplicity
55
Rate Limits
10

🔒 Security

TLS Enforcement
60
Auth Strength
55
Scope Granularity
10
Dep. Hygiene
45
Secret Handling
65

Security model appears to rely on (a) optional bearer token for plugin connections and (b) optional synchronous authorization webhook; analytics webhooks include a token and HMAC signature field description (when webhook-token configured). TLS is not explicitly mandated in docs excerpt (examples use http://localhost; production guidance mentions using HTTPS for webhook endpoints). Scope granularity for authorization is not described. Fire-and-forget analytics webhook failures are logged but not blocking.

⚡ Reliability

Uptime/SLA
0
Version Stability
45
Breaking Changes
50
Error Recovery
70
AF Security Reliability

Best When

You have a long-running .NET process (e.g., Unity Editor or desktop app) and want MCP clients to interact with that live instance through a persistent bridge and strongly-typed tool schemas.

Avoid When

You cannot reliably secure SignalR and MCP endpoints (e.g., no TLS/auth, no allowlists, or fail-open authorization).

Use Cases

  • Expose Unity/WPF/Game-server running state to an MCP-capable AI assistant without repeatedly spawning new processes
  • Build MCP-powered internal copilots that can call .NET business logic (tools) and return results/resources
  • Connect multiple long-lived .NET apps to a central MCP bridge for interactive workflows
  • Add observability via analytics webhooks and gate connections via an authorization webhook

Not For

  • Public internet deployments without hardening the auth/network layer
  • Use cases requiring strict, well-defined tool-selection behavior without fuzzy matching risk
  • Organizations needing a fully specified REST/OpenAPI contract or SDK for non-.NET ecosystems
  • Teams that require explicit, documented idempotency semantics for tool calls

Interface

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

Authentication

Methods: Bearer token (server-side 'token' / MCP_PLUGIN_TOKEN) for connecting plugins Authorization webhook gating (webhook-authorization-url) with fail-open/fail-closed behavior Webhook token for analytics/authorization webhooks (webhook-token) via header (webhook-header default X-Webhook-Token)
OAuth: No Scopes: No

Auth is primarily described via a bearer-token requirement for connecting plugins plus optional connection authorization webhook. OAuth/scopes are not indicated.

Pricing

Free tier: No
Requires CC: No

Open-source library (NuGet badge shown). No hosted pricing described.

Agent Metadata

Pagination
none
Idempotent
False
Retry Guidance
Not documented

Known Gotchas

  • Fuzzy method matching (method name match level) can lead to unexpected tool selection if multiple similar method names exist
  • Tool side effects may not be idempotent; callers should consider retry safety
  • Transport configuration matters: client-transport=stdio vs streamableHttp impacts how the bridge accepts MCP clients
  • Authorization webhook may be configured fail-open; for security-sensitive deployments prefer fail-closed (fail-open=false)

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

8642
Packages Evaluated
17761
Need Evaluation
586
Need Re-evaluation
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