internal/mcp: add telemetry for MCP tool usage

ethanalee-work · ethanalee-work · commit c312a17ecac1 · 2025-09-12T15:24:47.000-07:00
- add new counters for MCP tool usage. Fixes golang/go#75448 Change-Id: I966efe12da4432f00b00d9eb2c68b1ea4d6e8140 Reviewed-on: https://go-review.googlesource.com/c/tools/+/703358 Reviewed-by: Robert Findley <rfindley@google.com> LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/gopls/internal/mcp/context.go b/gopls/internal/mcp/context.go
@@ -32,6 +32,7 @@ type ContextParams struct {
 }
 
 func (h *handler) contextHandler(ctx context.Context, req *mcp.CallToolRequest, params ContextParams) (*mcp.CallToolResult, any, error) {
+	countGoContextMCP.Inc()
 	fh, snapshot, release, err := h.fileOf(ctx, params.File)
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/counters.go b/gopls/internal/mcp/counters.go
@@ -0,0 +1,23 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package mcp
+
+import "golang.org/x/telemetry/counter"
+
+// Proposed counters for evaluating usage of Go MCP Server tools. These counters
+// increment when a user utilizes a specific Go MCP tool.
+var (
+	countGoContextMCP          = counter.New("gopls/mcp-tool:go_context")
+	countGoDiagnosticsMCP      = counter.New("gopls/mcp-tool:go_diagnostics")
+	countGoFileContextMCP      = counter.New("gopls/mcp-tool:go_file_context")
+	countGoFileDiagnosticsMCP  = counter.New("gopls/mcp-tool:go_file_diagnostics")
+	countGoFileMetadataMCP     = counter.New("gopls/mcp-tool:go_file_metadata")
+	countGoPackageAPIMCP       = counter.New("gopls/mcp-tool:go_package_api")
+	countGoReferencesMCP       = counter.New("gopls/mcp-tool:go_references")
+	countGoSearchMCP           = counter.New("gopls/mcp-tool:go_search")
+	countGoSymbolReferencesMCP = counter.New("gopls/mcp-tool:go_symbol_references")
+	countGoWorkspaceMCP        = counter.New("gopls/mcp-tool:go_workspace")
+	countGoVulncheckMCP        = counter.New("gopls/mcp-tool:go_vulncheck")
+)
diff --git a/gopls/internal/mcp/file_context.go b/gopls/internal/mcp/file_context.go
@@ -21,6 +21,7 @@ type fileContextParams struct {
 }
 
 func (h *handler) fileContextHandler(ctx context.Context, req *mcp.CallToolRequest, params fileContextParams) (*mcp.CallToolResult, any, error) {
+	countGoFileContextMCP.Inc()
 	fh, snapshot, release, err := h.fileOf(ctx, params.File)
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/file_diagnostics.go b/gopls/internal/mcp/file_diagnostics.go
@@ -29,6 +29,7 @@ type diagnosticsParams struct {
 }
 
 func (h *handler) fileDiagnosticsHandler(ctx context.Context, req *mcp.CallToolRequest, params diagnosticsParams) (*mcp.CallToolResult, any, error) {
+	countGoFileDiagnosticsMCP.Inc()
 	fh, snapshot, release, err := h.fileOf(ctx, params.File)
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/file_metadata.go b/gopls/internal/mcp/file_metadata.go
@@ -17,6 +17,7 @@ type fileMetadataParams struct {
 }
 
 func (h *handler) fileMetadataHandler(ctx context.Context, req *mcp.CallToolRequest, params fileMetadataParams) (*mcp.CallToolResult, any, error) {
+	countGoFileMetadataMCP.Inc()
 	fh, snapshot, release, err := h.fileOf(ctx, params.File)
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/outline.go b/gopls/internal/mcp/outline.go
@@ -18,6 +18,7 @@ type outlineParams struct {
 }
 
 func (h *handler) outlineHandler(ctx context.Context, req *mcp.CallToolRequest, params outlineParams) (*mcp.CallToolResult, any, error) {
+	countGoPackageAPIMCP.Inc()
 	snapshot, release, err := h.snapshot()
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/references.go b/gopls/internal/mcp/references.go
@@ -21,6 +21,7 @@ type findReferencesParams struct {
 }
 
 func (h *handler) referencesHandler(ctx context.Context, req *mcp.CallToolRequest, params findReferencesParams) (*mcp.CallToolResult, any, error) {
+	countGoReferencesMCP.Inc()
 	fh, snapshot, release, err := h.session.FileOf(ctx, params.Location.URI)
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/search.go b/gopls/internal/mcp/search.go
@@ -18,6 +18,7 @@ type searchParams struct {
 }
 
 func (h *handler) searchHandler(ctx context.Context, req *mcp.CallToolRequest, params searchParams) (*mcp.CallToolResult, any, error) {
+	countGoSearchMCP.Inc()
 	query := params.Query
 	if len(query) == 0 {
 		return nil, nil, fmt.Errorf("empty query")
diff --git a/gopls/internal/mcp/symbol_references.go b/gopls/internal/mcp/symbol_references.go
@@ -29,6 +29,7 @@ type symbolReferencesParams struct {
 // It finds all references to the requested symbol and describes their
 // locations.
 func (h *handler) symbolReferencesHandler(ctx context.Context, req *mcp.CallToolRequest, params symbolReferencesParams) (*mcp.CallToolResult, any, error) {
+	countGoSymbolReferencesMCP.Inc()
 	fh, snapshot, release, err := h.fileOf(ctx, params.File)
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/vulncheck.go b/gopls/internal/mcp/vulncheck.go
@@ -33,6 +33,7 @@ type VulncheckResultOutput struct {
 }
 
 func (h *handler) vulncheckHandler(ctx context.Context, req *mcp.CallToolRequest, params *vulncheckParams) (*mcp.CallToolResult, *VulncheckResultOutput, error) {
+	countGoVulncheckMCP.Inc()
 	snapshot, release, err := h.snapshot()
 	if err != nil {
 		return nil, nil, err
diff --git a/gopls/internal/mcp/workspace.go b/gopls/internal/mcp/workspace.go
@@ -20,6 +20,7 @@ import (
 )
 
 func (h *handler) workspaceHandler(ctx context.Context, req *mcp.CallToolRequest, _ any) (*mcp.CallToolResult, any, error) {
+	countGoWorkspaceMCP.Inc()
 	var summary bytes.Buffer
 	views := h.session.Views()
 	for _, v := range views {
diff --git a/gopls/internal/mcp/workspace_diagnostics.go b/gopls/internal/mcp/workspace_diagnostics.go
@@ -23,6 +23,7 @@ type workspaceDiagnosticsParams struct {
 }
 
 func (h *handler) workspaceDiagnosticsHandler(ctx context.Context, req *mcp.CallToolRequest, params workspaceDiagnosticsParams) (*mcp.CallToolResult, any, error) {
+	countGoDiagnosticsMCP.Inc()
 	var (
 		fh       file.Handle
 		snapshot *cache.Snapshot

Original file line number	Diff line number	Diff line change
`@@ -32,6 +32,7 @@ type ContextParams struct {`
`32`	`32`	`}`
`33`	`33`
`34`	`34`	`func (h handler) contextHandler(ctx context.Context, req mcp.CallToolRequest, params ContextParams) (*mcp.CallToolResult, any, error) {`
	`35`	`+ countGoContextMCP.Inc()`
`35`	`36`	`fh, snapshot, release, err := h.fileOf(ctx, params.File)`
`36`	`37`	`if err != nil {`
`37`	`38`	`return nil, nil, err`
Original file line number	Diff line number	Diff line change
`@@ -21,6 +21,7 @@ type fileContextParams struct {`
`21`	`21`	`}`
`22`	`22`
`23`	`23`	`func (h handler) fileContextHandler(ctx context.Context, req mcp.CallToolRequest, params fileContextParams) (*mcp.CallToolResult, any, error) {`
	`24`	`+ countGoFileContextMCP.Inc()`
`24`	`25`	`fh, snapshot, release, err := h.fileOf(ctx, params.File)`
`25`	`26`	`if err != nil {`
`26`	`27`	`return nil, nil, err`
Original file line number	Diff line number	Diff line change
`@@ -29,6 +29,7 @@ type diagnosticsParams struct {`
`29`	`29`	`}`
`30`	`30`
`31`	`31`	`func (h handler) fileDiagnosticsHandler(ctx context.Context, req mcp.CallToolRequest, params diagnosticsParams) (*mcp.CallToolResult, any, error) {`
	`32`	`+ countGoFileDiagnosticsMCP.Inc()`
`32`	`33`	`fh, snapshot, release, err := h.fileOf(ctx, params.File)`
`33`	`34`	`if err != nil {`
`34`	`35`	`return nil, nil, err`
Original file line number	Diff line number	Diff line change
`@@ -17,6 +17,7 @@ type fileMetadataParams struct {`
`17`	`17`	`}`
`18`	`18`
`19`	`19`	`func (h handler) fileMetadataHandler(ctx context.Context, req mcp.CallToolRequest, params fileMetadataParams) (*mcp.CallToolResult, any, error) {`
	`20`	`+ countGoFileMetadataMCP.Inc()`
`20`	`21`	`fh, snapshot, release, err := h.fileOf(ctx, params.File)`
`21`	`22`	`if err != nil {`
`22`	`23`	`return nil, nil, err`
Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,7 @@ type outlineParams struct {`
`18`	`18`	`}`
`19`	`19`
`20`	`20`	`func (h handler) outlineHandler(ctx context.Context, req mcp.CallToolRequest, params outlineParams) (*mcp.CallToolResult, any, error) {`
	`21`	`+ countGoPackageAPIMCP.Inc()`
`21`	`22`	`snapshot, release, err := h.snapshot()`
`22`	`23`	`if err != nil {`
`23`	`24`	`return nil, nil, err`
Original file line number	Diff line number	Diff line change
`@@ -21,6 +21,7 @@ type findReferencesParams struct {`
`21`	`21`	`}`
`22`	`22`
`23`	`23`	`func (h handler) referencesHandler(ctx context.Context, req mcp.CallToolRequest, params findReferencesParams) (*mcp.CallToolResult, any, error) {`
	`24`	`+ countGoReferencesMCP.Inc()`
`24`	`25`	`fh, snapshot, release, err := h.session.FileOf(ctx, params.Location.URI)`
`25`	`26`	`if err != nil {`
`26`	`27`	`return nil, nil, err`
Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,7 @@ type searchParams struct {`
`18`	`18`	`}`
`19`	`19`
`20`	`20`	`func (h handler) searchHandler(ctx context.Context, req mcp.CallToolRequest, params searchParams) (*mcp.CallToolResult, any, error) {`
	`21`	`+ countGoSearchMCP.Inc()`
`21`	`22`	`query := params.Query`
`22`	`23`	`if len(query) == 0 {`
`23`	`24`	`return nil, nil, fmt.Errorf("empty query")`
Original file line number	Diff line number	Diff line change
`@@ -33,6 +33,7 @@ type VulncheckResultOutput struct {`
`33`	`33`	`}`
`34`	`34`
`35`	`35`	`func (h handler) vulncheckHandler(ctx context.Context, req mcp.CallToolRequest, params vulncheckParams) (mcp.CallToolResult, *VulncheckResultOutput, error) {`
	`36`	`+ countGoVulncheckMCP.Inc()`
`36`	`37`	`snapshot, release, err := h.snapshot()`
`37`	`38`	`if err != nil {`
`38`	`39`	`return nil, nil, err`