feat(observability): add MCP tool name logging in access log

* Include tool name from request in access log entries
* Update user agent header in HTTP requests
* Add tests for MCP tool name logging

cmd/amcs-cli/cmd/root.go

@@ -21,6 +21,8 @@ var (
 	cfg        Config
 )
 
+const cliUserAgent = "amcs-cli/0.0.1"
+
 var rootCmd = &cobra.Command{
 	Use:           "amcs-cli",
 	Short:         "CLI for connecting to a remote AMCS MCP server",
@@ -114,6 +116,9 @@ func (t *bearerTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 		base = http.DefaultTransport
 	}
 	clone := req.Clone(req.Context())
+	if strings.TrimSpace(clone.Header.Get("User-Agent")) == "" {
+		clone.Header.Set("User-Agent", cliUserAgent)
+	}
 	if strings.TrimSpace(t.token) != "" {
 		clone.Header.Set("Authorization", "Bearer "+t.token)
 	}

cmd/amcs-cli/cmd/root_test.go

@@ -8,11 +8,15 @@ import (
 
 func TestBearerTransportFormatsBearerToken(t *testing.T) {
 	const want = "Bearer X"
+	const wantUA = "amcs-cli/0.0.1"
 
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if got := r.Header.Get("Authorization"); got != want {
 			t.Fatalf("Authorization header = %q, want %q", got, want)
 		}
+		if got := r.Header.Get("User-Agent"); got != wantUA {
+			t.Fatalf("User-Agent header = %q, want %q", got, wantUA)
+		}
 		w.WriteHeader(http.StatusNoContent)
 	}))
 	defer ts.Close()