Merge pull request #175 from dosentmatter/fix/154-user-id-w-prefix

fix: support user id with w prefix

Author: korotovsky

pkg/handler/conversations.go

@@ -998,10 +998,15 @@ func (ch *ConversationsHandler) parseParamsToolSearch(req mcp.CallToolRequest) (
 	}, nil
 }
 
+// Slack user IDs may begin with U or W: https://docs.slack.dev/changelog/2016/08/11/user-id-format-changes
+func isSlackUserIDPrefix(s string) bool {
+	return strings.HasPrefix(s, "U") || strings.HasPrefix(s, "W")
+}
+
 func (ch *ConversationsHandler) paramFormatUser(raw string) (string, error) {
 	users := ch.apiProvider.ProvideUsersMap()
 	raw = strings.TrimSpace(raw)
-	if strings.HasPrefix(raw, "U") {
+	if isSlackUserIDPrefix(raw) {
 		u, ok := users.Users[raw]
 		if !ok {
 			return "", fmt.Errorf("user %q not found", raw)

pkg/handler/conversations_test.go

@@ -590,3 +590,24 @@ func TestUnitLimitByExpression_Invalid(t *testing.T) {
 		})
 	}
 }
+
+func TestUnitIsSlackUserIDPrefix(t *testing.T) {
+	tests := []struct {
+		name string
+		s    string
+		want bool
+	}{
+		{"U prefix", "U0123ABCD", true},
+		{"W prefix", "W0123ABCD", true},
+		{"plain name not ID", "alice", false},
+		{"empty", "", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := isSlackUserIDPrefix(tt.s)
+			if got != tt.want {
+				t.Errorf("isSlackUserIDPrefix(%q) = %v, want %v", tt.s, got, tt.want)
+			}
+		})
+	}
+}