074dc6cdbd## Summary - Rename `interceptors/mcpserver/` → `interceptors/extension/`, replacing the `Server` wrapper with a lightweight `Extension` that can install itself on any `*mcp.Server` - Remove the stored `*mcp.Server` field — `Extension` is now a pure interceptor container with no server reference - Add `Install(server)` method to register JSON-RPC methods and init middleware on a given server - Update `LocalChain(ctx)` → `LocalChain(ctx, server)` to accept the server as a parameter - Remove `MCPServer()`, `Run()`, and `NewStreamableHTTPHandler()` wrapper methods — users interact with `mcp.Server` directly - Update all examples, tests, and documentation to use the new API ## Why `mcpserver.Server` pretended to *be* the server — it had `Run()`, `NewStreamableHTTPHandler()`, etc. — but it could never cover the full `*mcp.Server` API, so users constantly needed `MCPServer()` to unwrap it. `Extension` doesn't pretend to be the server. It's a pure interceptor container that can install itself on any server (or multiple servers) on the fly. No stored server reference, no wrapping, no delegation surface to maintain. ### Before ```go mcpServer := mcp.NewServer(...) srv := mcpserver.NewServer(mcpServer) srv.AddInterceptor(v) chain, err := srv.LocalChain(ctx) ``` ### After ```go mcpServer := mcp.NewServer(...) ext := extension.New() ext.AddInterceptor(v) ext.Install(mcpServer) chain, err := ext.LocalChain(ctx, mcpServer) ``` Signed-off-by: Kurt Degiorgio <kdegiorgio@bloomberg.net>
60 lines
1.9 KiB
Markdown
60 lines
1.9 KiB
Markdown
# MCP Interceptors - Go Implementation
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Go implementation of the MCP Interceptor Extension based on
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[SEP-1763](https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1763).
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Note: Currently the MCP SDK is vendored, in-order to add the Protocol Methods needed for interceptors.
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## Quick Start
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```go
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mcpServer := mcp.NewServer(&mcp.Implementation{
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Name: "my-server",
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Version: "0.1.0",
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}, nil)
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// Create an extension and register interceptors.
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ext := extension.New()
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// Register a validator that blocks dangerous tool calls.
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ext.AddInterceptor(&interceptors.Validator{
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Metadata: interceptors.Metadata{
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Name: "block-dangerous",
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Hook: interceptors.Hook{
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Events: []string{interceptors.EventToolsCall},
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Phase: interceptors.PhaseRequest,
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},
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Mode: interceptors.ModeEnforce,
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},
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Handler: func(_ context.Context, inv *interceptors.Invocation) (*interceptors.ValidationResult, error) {
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raw := inv.Payload.(json.RawMessage)
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var params struct{ Name string `json:"name"` }
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json.Unmarshal(raw, ¶ms)
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// validate the request...
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return &interceptors.ValidationResult{Valid: true}, nil
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},
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})
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// Install on the server and create a chain for middleware.
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ext.Install(mcpServer)
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chain, err := ext.LocalChain(ctx, mcpServer)
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mcpServer.AddReceivingMiddleware(gomiddleware.Middleware(chain))
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mcpServer.Run(context.Background(), &mcp.StdioTransport{})
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```
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See [`examples/`](examples/) for complete working examples.
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## Documentation
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- [**DESIGN.md**](doc/DESIGN.md) — architecture, execution model, integration
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with the go-sdk.
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- [**PERFORMANCE.md**](doc/PERFORMANCE.md) — per-request cost model, allocation
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summary, and optimization notes.
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- [**CONFORMANCE.md**](doc/CONFORMANCE.md) — SEP conformance status.
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Package API documentation is available via `go doc`:
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```sh
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go doc github.com/modelcontextprotocol/ext-interceptors/go/sdk/interceptors
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```
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