Index: modeshape-jcr/src/main/java/org/modeshape/jcr/AbstractJcrNode.java
===================================================================
--- modeshape-jcr/src/main/java/org/modeshape/jcr/AbstractJcrNode.java	(revision 1790)
+++ modeshape-jcr/src/main/java/org/modeshape/jcr/AbstractJcrNode.java	(working copy)
@@ -1213,6 +1213,61 @@ abstract class AbstractJcrNode extends AbstractJcrItem implements javax.jcr.Node
         return editor.createChild(childName, desiredUuid, childPrimaryTypeName);
     }
 
+    /**
+     * Performs a "best effort" check on whether a node can be added at the given relative path from this node with the given
+     * primary node type (if one is specified).
+     * <p>
+     * Note that a result of {@code true} from this method does not guarantee that a call to {@code #addNode(String, String)} with
+     * the same arguments will succeed, but a result of {@code false} guarantees that it would fail (assuming that the current
+     * repository state does not change).
+     * </p>
+     * 
+     * @param relPath the relative path at which the node would be added; may not be null
+     * @param primaryNodeTypeName the primary type that would be used for the node; null indicates that a default primary type
+     *        should be used if possible
+     * @return false if the node could not be added for any reason; true if the node <i>might</i> be able to be added
+     * @throws RepositoryException if an error occurs accessing the repository
+     */
+    final boolean canAddNode( String relPath,
+                              String primaryNodeTypeName ) throws RepositoryException {
+        CheckArg.isNotEmpty(relPath, relPath);
+
+        if (isLocked() && !holdsLock()) {
+            return false;
+        }
+
+        // Determine the path ...
+        Path path = null;
+        try {
+            path = cache.pathFactory().create(relPath);
+        } catch (org.modeshape.graph.property.ValueFormatException e) {
+            return false;
+        }
+        if (path.size() == 0) {
+            return false;
+        }
+        if (path.getLastSegment().getIndex() > 1 || relPath.endsWith("]")) {
+            return false;
+        }
+        if (path.size() > 1) {
+            // The only segment in the path is the child name ...
+            Path parentPath = path.getParent();
+            try {
+                // Find the parent node ...
+                cache.findNode(nodeId, location.getPath(), parentPath);
+            } catch (RepositoryException e) {
+                return false;
+            }
+        }
+
+        // Determine the name for the primary node type
+        if (primaryNodeTypeName != null) {
+            if (!session().nodeTypeManager().hasNodeType(primaryNodeTypeName)) return false;
+        }
+
+        return true;
+    }
+
     protected final Property removeExistingValuedProperty( String name ) throws ConstraintViolationException, RepositoryException {
         AbstractJcrProperty property = cache.findJcrProperty(nodeId, location.getPath(), nameFrom(name));
         if (property != null) {
Index: modeshape-jcr/src/main/java/org/modeshape/jcr/JcrSession.java
===================================================================
--- modeshape-jcr/src/main/java/org/modeshape/jcr/JcrSession.java	(revision 1790)
+++ modeshape-jcr/src/main/java/org/modeshape/jcr/JcrSession.java	(working copy)
@@ -457,6 +457,45 @@ class JcrSession implements Session {
     }
 
     /**
+     * Makes a "best effort" determination of whether the given method can be successfully called on the given target with the
+     * given arguments. A return value of {@code false} indicates that the method would not succeed. A return value of {@code
+     * true} indicates that the method <i>might</i> succeed.
+     * 
+     * @param methodName the method to invoke; may not be null
+     * @param target the object on which to invoke it; may not be null
+     * @param arguments the arguments to pass to the method; varies depending on the method
+     * @return
+     * @throws IllegalArgumentException
+     * @throws RepositoryException
+     */
+    public boolean hasCapability( String methodName,
+                                  Object target,
+                                  Object[] arguments ) throws IllegalArgumentException, RepositoryException {
+        CheckArg.isNotEmpty(methodName, "methodName");
+        CheckArg.isNotNull(target, "target");
+
+        if (target instanceof AbstractJcrNode) {
+            AbstractJcrNode node = (AbstractJcrNode)target;
+            if ("addNode".equals(methodName)) {
+                CheckArg.hasSizeOfAtLeast(arguments, 1, "arguments");
+                CheckArg.hasSizeOfAtMost(arguments, 2, "arguments");
+                CheckArg.isInstanceOf(arguments[0], String.class, "arguments[0]");
+
+                String relPath = (String) arguments[0];
+                String primaryNodeTypeName = null;
+                if (arguments.length > 1) {
+                    CheckArg.isInstanceOf(arguments[1], String.class, "arguments[1]");
+                    primaryNodeTypeName = (String) arguments[1];
+                }
+
+                return node.canAddNode(relPath, primaryNodeTypeName);
+            }
+        }
+
+        return true;
+    }
+
+    /**
      * {@inheritDoc}
      * 
      * @see javax.jcr.Session#exportDocumentView(java.lang.String, org.xml.sax.ContentHandler, boolean, boolean)
Index: modeshape-jcr/src/test/java/org/modeshape/jcr/JcrSessionTest.java
===================================================================
--- modeshape-jcr/src/test/java/org/modeshape/jcr/JcrSessionTest.java	(revision 1790)
+++ modeshape-jcr/src/test/java/org/modeshape/jcr/JcrSessionTest.java	(working copy)
@@ -467,4 +467,17 @@ public class JcrSessionTest extends AbstractSessionTest {
         Node fileNode = folderNode.addNode("fileNode", "nt:file");
         assertThat(fileNode.hasProperty("jcr:created"), is(true));
     }
+
+    @Test
+    public void shouldHaveCapabilityToPerformValidAddNode() throws Exception {
+        assertTrue(session.hasCapability("addNode", session.getRootNode(), new String[] {"someNewNode"}));
+        assertTrue(session.hasCapability("addNode", session.getRootNode(), new String[] {"someNewNode", "nt:unstructured"}));
+    }
+
+    @Test
+    public void shouldNotHaveCapabilityToPerformInvalidAddNode() throws Exception {
+        assertTrue(!session.hasCapability("addNode", session.getRootNode(), new String[] {"someNewNode[2]"}));
+        assertTrue(!session.hasCapability("addNode", session.getRootNode(), new String[] {"someNewNode", "nt:invalidType"}));
+    }
+
 }