From 0b09f3ad5a0b62f2cc538afdc40968855b534b6d Mon Sep 17 00:00:00 2001
From: Rob Findley <rfindley@google.com>
Date: Wed, 14 May 2025 17:58:58 +0000
Subject: [PATCH] internal/mcp: hide CancelledParams

Since cancellation is handled transparently, this type need not be
exported.

Change-Id: Id4e195b0c3bd49eca52587032a027ffa449eb9d1
Reviewed-on: https://go-review.googlesource.com/c/tools/+/672796
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Sam Thanawalla <samthanawalla@google.com>
---
 mcp/generate.go  |  2 +-
 mcp/protocol.go  | 22 +++++++++++-----------
 mcp/transport.go |  4 ++--
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/mcp/generate.go b/mcp/generate.go
index 6ac0a65..cfffef8 100644
--- a/mcp/generate.go
+++ b/mcp/generate.go
@@ -66,7 +66,7 @@ var declarations = config{
 	"CallToolResult": {},
 	"CancelledNotification": {
 		Name:   "-",
-		Fields: config{"Params": {Name: "CancelledParams"}},
+		Fields: config{"Params": {Name: "cancelledParams"}},
 	},
 	"ClientCapabilities": {},
 	"GetPromptRequest": {
diff --git a/mcp/protocol.go b/mcp/protocol.go
index 2664ce3..5450f71 100644
--- a/mcp/protocol.go
+++ b/mcp/protocol.go
@@ -54,17 +54,6 @@ type CallToolResult struct {
 	IsError bool `json:"isError,omitempty"`
 }
 
-type CancelledParams struct {
-	// An optional string describing the reason for the cancellation. This MAY be
-	// logged or presented to the user.
-	Reason string `json:"reason,omitempty"`
-	// The ID of the request to cancel.
-	//
-	// This MUST correspond to the ID of a request previously issued in the same
-	// direction.
-	RequestID any `json:"requestId"`
-}
-
 // Capabilities a client may support. Known capabilities are defined here, in
 // this schema, but this is not a closed set: any client can define its own,
 // additional capabilities.
@@ -315,6 +304,17 @@ type ToolAnnotations struct {
 	Title string `json:"title,omitempty"`
 }
 
+type cancelledParams struct {
+	// An optional string describing the reason for the cancellation. This MAY be
+	// logged or presented to the user.
+	Reason string `json:"reason,omitempty"`
+	// The ID of the request to cancel.
+	//
+	// This MUST correspond to the ID of a request previously issued in the same
+	// direction.
+	RequestID any `json:"requestId"`
+}
+
 // Describes the name and version of an MCP implementation.
 type implementation struct {
 	Name    string `json:"name"`
diff --git a/mcp/transport.go b/mcp/transport.go
index f69299d..f0fda45 100644
--- a/mcp/transport.go
+++ b/mcp/transport.go
@@ -126,7 +126,7 @@ type canceller struct {
 // Preempt implements jsonrpc2.Preempter.
 func (c *canceller) Preempt(ctx context.Context, req *jsonrpc2.Request) (result any, err error) {
 	if req.Method == "notifications/cancelled" {
-		var params CancelledParams
+		var params cancelledParams
 		if err := json.Unmarshal(req.Params, &params); err != nil {
 			return nil, err
 		}
@@ -151,7 +151,7 @@ func call(ctx context.Context, conn *jsonrpc2.Connection, method string, params,
 		return fmt.Errorf("calling %q: %w", method, ErrConnectionClosed)
 	case ctx.Err() != nil:
 		// Notify the peer of cancellation.
-		err := conn.Notify(xcontext.Detach(ctx), "notifications/cancelled", &CancelledParams{
+		err := conn.Notify(xcontext.Detach(ctx), "notifications/cancelled", &cancelledParams{
 			Reason:    ctx.Err().Error(),
 			RequestID: call.ID().Raw(),
 		})