--- a/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/Probe.java	Tue Apr 21 10:47:43 2015 -0700
+++ b/graal/com.oracle.truffle.api/src/com/oracle/truffle/api/instrument/Probe.java	Tue Apr 21 15:56:48 2015 -0700
@@ -39,7 +39,8 @@
 /**
  * A <em>binding</em> between:
  * <ol>
- * <li>A program location in an executing Truffle AST (defined by a {@link SourceSection}), and</li>
+ * <li>A program location in an executing Truffle AST (corresponding to a {@link SourceSection}),
+ * and</li>
  * <li>A dynamically managed collection of "attached" {@linkplain Instrument Instruments} that
  * receive event notifications on behalf of external clients.</li>
  * </ol>
@@ -97,7 +98,7 @@
  * @see ProbeListener
  * @see SyntaxTag
  */
-public final class Probe implements SyntaxTagged {
+public final class Probe {
 
     private static final List<ASTProber> astProbers = new ArrayList<>();
 
@@ -251,11 +252,18 @@
         }
     }
 
+    /**
+     * Is this node tagged as belonging to a particular human-sensible category of language
+     * constructs?
+     */
     public boolean isTaggedAs(SyntaxTag tag) {
         assert tag != null;
         return tags.contains(tag);
     }
 
+    /**
+     * In which user-sensible categories has this node been tagged (<em>empty set</em> if none).
+     */
     public Collection<SyntaxTag> getSyntaxTags() {
         return Collections.unmodifiableCollection(tags);
     }