diff --git a/src/OpenTracing/NoopSpan.php b/src/OpenTracing/NoopSpan.php
index <HASH>..<HASH> 100644
--- a/src/OpenTracing/NoopSpan.php
+++ b/src/OpenTracing/NoopSpan.php
@@ -27,7 +27,10 @@ final class NoopSpan implements Span
     {
     }
 
-    public function setTag($tag)
+    /**
+     * {@inheritdoc}
+     */
+    public function withTag($tag)
     {
     }
 
@@ -39,7 +42,10 @@ final class NoopSpan implements Span
     {
     }
 
-    public function setBaggageItem($key, $value)
+    /**
+     * {@inheritdoc}
+     */
+    public function withBaggageItem($key, $value)
     {
     }
 
diff --git a/src/OpenTracing/Span.php b/src/OpenTracing/Span.php
index <HASH>..<HASH> 100644
--- a/src/OpenTracing/Span.php
+++ b/src/OpenTracing/Span.php
@@ -34,7 +34,7 @@ interface Span
      * @param Tag|string $tag
      * @return mixed
      */
-    public function setTag($tag/** [, $tagValue] **/);
+    public function withTag($tag/** [, $tagValue] **/);
 
     /**
      * @param array, LogField[]|string[string] $logs
@@ -54,7 +54,7 @@ interface Span
      * @param string $value
      * @return Span
      */
-    public function setBaggageItem($key, $value);
+    public function withBaggageItem($key, $value);
 
     /**
      * @param string $key
Changes the name for setters.