diff --git a/IPython/html/static/notebook/js/codecell.js b/IPython/html/static/notebook/js/codecell.js
index b823fa2..95d6269 100644
--- a/IPython/html/static/notebook/js/codecell.js
+++ b/IPython/html/static/notebook/js/codecell.js
@@ -244,12 +244,22 @@ var IPython = (function (IPython) {
         this.set_input_prompt('*');
         this.element.addClass("running");
         var callbacks = {
-            'execute_reply': $.proxy(this._handle_execute_reply, this),
-            'output': $.proxy(this.output_area.handle_output, this.output_area),
-            'clear_output': $.proxy(this.output_area.handle_clear_output, this.output_area),
-            'set_next_input': $.proxy(this._handle_set_next_input, this),
-            'input_request': $.proxy(this._handle_input_request, this)
-        };
+            shell : {
+                reply : $.proxy(this._handle_execute_reply, this),
+                payload : {
+                    set_next_input : $.proxy(this._handle_set_next_input, this),
+                    page : function (payload) {
+                        $([IPython.events]).trigger('open_with_text.Pager', payload);
+                    }
+                }
+            },
+            iopub : {
+                output : $.proxy(this.output_area.handle_output, this.output_area),
+                clear_output : $.proxy(this.output_area.handle_clear_output, this.output_area),
+            },
+            input : $.proxy(this._handle_input_request, this)
+        }
+        
         this.last_msg_id = this.kernel.execute(this.get_text(), callbacks, {silent: false, store_history: true});
     };
 
@@ -257,8 +267,8 @@ var IPython = (function (IPython) {
      * @method _handle_execute_reply
      * @private
      */
-    CodeCell.prototype._handle_execute_reply = function (content) {
-        this.set_input_prompt(content.execution_count);
+    CodeCell.prototype._handle_execute_reply = function (msg) {
+        this.set_input_prompt(msg.content.execution_count);
         this.element.removeClass("running");
         $([IPython.events]).trigger('set_dirty.Notebook', {value: true});
     }
@@ -267,8 +277,8 @@ var IPython = (function (IPython) {
      * @method _handle_set_next_input
      * @private
      */
-    CodeCell.prototype._handle_set_next_input = function (text) {
-        var data = {'cell': this, 'text': text}
+    CodeCell.prototype._handle_set_next_input = function (payload) {
+        var data = {'cell': this, 'text': payload.text}
         $([IPython.events]).trigger('set_next_input.Notebook', data);
     }
 
@@ -276,8 +286,8 @@ var IPython = (function (IPython) {
      * @method _handle_input_request
      * @private
      */
-    CodeCell.prototype._handle_input_request = function (content) {
-        this.output_area.append_raw_input(content);
+    CodeCell.prototype._handle_input_request = function (msg) {
+        this.output_area.append_raw_input(msg);
     }
 
 
@@ -438,4 +448,4 @@ var IPython = (function (IPython) {
     IPython.CodeCell = CodeCell;
 
     return IPython;
-}(IPython));
\ No newline at end of file
+}(IPython));
diff --git a/IPython/html/static/notebook/js/completer.js b/IPython/html/static/notebook/js/completer.js
index 992c87f..b2b77b5 100644
--- a/IPython/html/static/notebook/js/completer.js
+++ b/IPython/html/static/notebook/js/completer.js
@@ -150,16 +150,17 @@ var IPython = (function (IPython) {
                 matched_text: ""
             })
         } else {
-            var callbacks = {
-                'complete_reply': $.proxy(this.finish_completing, this)
-            };
+            var callbacks = { shell : {
+                reply: $.proxy(this.finish_completing, this)
+            }};
             this.cell.kernel.complete(line, cur.ch, callbacks);
         }
     };
 
-    Completer.prototype.finish_completing = function (content) {
+    Completer.prototype.finish_completing = function (msg) {
         // let's build a function that wrap all that stuff into what is needed
         // for the new completer:
+        var content = msg.content;
         var matched_text = content.matched_text;
         var matches = content.matches;
 
diff --git a/IPython/html/static/notebook/js/outputarea.js b/IPython/html/static/notebook/js/outputarea.js
index 3307004..91886df 100644
--- a/IPython/html/static/notebook/js/outputarea.js
+++ b/IPython/html/static/notebook/js/outputarea.js
@@ -231,9 +231,10 @@ var IPython = (function (IPython) {
     };
 
 
-    OutputArea.prototype.handle_output = function (msg_type, content) {
+    OutputArea.prototype.handle_output = function (msg) {
         var json = {};
-        json.output_type = msg_type;
+        var msg_type = json.output_type = msg.header.msg_type;
+        var content = msg.content;
         if (msg_type === "stream") {
             json.text = content.data;
             json.stream = content.name;
@@ -564,9 +565,10 @@ var IPython = (function (IPython) {
         element.append(toinsert);
     };
 
-    OutputArea.prototype.append_raw_input = function (content) {
+    OutputArea.prototype.append_raw_input = function (msg) {
         var that = this;
         this.expand();
+        var content = msg.content;
         var area = this.create_output_area();
         
         // disable any other raw_inputs, if they are left around
@@ -618,8 +620,8 @@ var IPython = (function (IPython) {
     }
 
 
-    OutputArea.prototype.handle_clear_output = function (content) {
-        this.clear_output(content.wait);
+    OutputArea.prototype.handle_clear_output = function (msg) {
+        this.clear_output(msg.content.wait);
     };
 
 
diff --git a/IPython/html/static/notebook/js/tooltip.js b/IPython/html/static/notebook/js/tooltip.js
index 9c3679e..ca57880 100644
--- a/IPython/html/static/notebook/js/tooltip.js
+++ b/IPython/html/static/notebook/js/tooltip.js
@@ -222,12 +222,12 @@ var IPython = (function (IPython) {
 
 
     Tooltip.prototype._request_tooltip = function (cell, line) {
-        var callbacks = {
-            'object_info_reply': $.proxy(this._show, this)
-        }
+        var callbacks = { shell : {
+            reply : $.proxy(this._show, this)
+        }};
         var oir_token = this.extract_oir_token(line);
         var msg_id = cell.kernel.object_info_request(oir_token, callbacks);
-    }
+    };
 
     // make an imediate completion request
     Tooltip.prototype.request = function (cell, hide_if_no_docstring) {
@@ -301,7 +301,8 @@ var IPython = (function (IPython) {
     Tooltip.prototype._show = function (reply) {
         // move the bubble if it is not hidden
         // otherwise fade it
-        this.name = reply.name;
+        var content = reply.content;
+        this.name = content.name;
 
         // do some math to have the tooltip arrow on more or less on left or right
         // width of the editor
@@ -334,20 +335,20 @@ var IPython = (function (IPython) {
         });
 
         // build docstring
-        var defstring = reply.call_def;
+        var defstring = content.call_def;
         if (defstring == null) {
-            defstring = reply.init_definition;
+            defstring = content.init_definition;
         }
         if (defstring == null) {
-            defstring = reply.definition;
+            defstring = content.definition;
         }
 
-        var docstring = reply.call_docstring;
+        var docstring = content.call_docstring;
         if (docstring == null) {
-            docstring = reply.init_docstring;
+            docstring = content.init_docstring;
         }
         if (docstring == null) {
-            docstring = reply.docstring;
+            docstring = content.docstring;
         }
 
         if (docstring == null) {
diff --git a/IPython/html/static/services/kernels/js/kernel.js b/IPython/html/static/services/kernels/js/kernel.js
index 9a10880..a8539fb 100644
--- a/IPython/html/static/services/kernels/js/kernel.js
+++ b/IPython/html/static/services/kernels/js/kernel.js
@@ -239,7 +239,7 @@ var IPython = (function (IPython) {
         this.shell_channel.send(JSON.stringify(msg));
         this.set_callbacks_for_msg(msg.header.msg_id, callbacks);
         return msg.header.msg_id;
-    }
+    };
 
     /**
      * Get info on object asynchronoulsy
@@ -340,7 +340,7 @@ var IPython = (function (IPython) {
             allow_stdin : false
         };
         callbacks = callbacks || {};
-        if (callbacks.input_request !== undefined) {
+        if (callbacks.input !== undefined) {
             content.allow_stdin = true;
         }
         $.extend(true, content, options);
@@ -431,11 +431,22 @@ var IPython = (function (IPython) {
             delete this._msg_callbacks[msg_id];
         }
     };
-
-
+    
+    /* Set callbacks for a particular message.
+     * Callbacks should be a struct of the following form:
+     * shell : {
+     * 
+     * }
+    
+     */
     Kernel.prototype.set_callbacks_for_msg = function (msg_id, callbacks) {
         if (callbacks) {
-            this._msg_callbacks[msg_id] = callbacks;
+            // shallow-copy mapping, because we will modify it at the top level
+            var cbcopy = this._msg_callbacks[msg_id] = {};
+            cbcopy.shell = callbacks.shell;
+            cbcopy.iopub = callbacks.iopub;
+            cbcopy.input = callbacks.input;
+            this._msg_callbacks[msg_id] = cbcopy;
         }
     };
 
@@ -443,37 +454,40 @@ var IPython = (function (IPython) {
     Kernel.prototype._handle_shell_reply = function (e) {
         var reply = $.parseJSON(e.data);
         $([IPython.events]).trigger('shell_reply.Kernel', {kernel: this, reply:reply});
-        var header = reply.header;
         var content = reply.content;
         var metadata = reply.metadata;
-        var msg_type = header.msg_type;
-        var callbacks = this.get_callbacks_for_msg(reply.parent_header.msg_id);
-        if (callbacks !== undefined) {
-            var cb = callbacks[msg_type];
-            if (cb !== undefined) {
-                cb(content, metadata);
-            }
+        var parent_id = reply.parent_header.msg_id;
+        var callbacks = this.get_callbacks_for_msg(parent_id);
+        if (!callbacks || !callbacks.shell) {
+            return;
         }
-
-        if (content.payload !== undefined) {
-            var payload = content.payload || [];
-            this._handle_payload(callbacks, payload);
+        var shell_callbacks = callbacks.shell;
+        
+        // clear callbacks on shell
+        delete callbacks.shell;
+        delete callbacks.input;
+        if (!callbacks.iopub) {
+            this.clear_callbacks_for_msg(parent_id);
+        }
+        
+        if (shell_callbacks.reply !== undefined) {
+            shell_callbacks.reply(reply);
+        }
+        if (content.payload && shell_callbacks.payload) {
+            this._handle_payloads(content.payload, shell_callbacks.payload, reply);
         }
     };
 
 
-    Kernel.prototype._handle_payload = function (callbacks, payload) {
-        var l = payload.length;
+    Kernel.prototype._handle_payloads = function (payloads, payload_callbacks, msg) {
+        var l = payloads.length;
         // Payloads are handled by triggering events because we don't want the Kernel
         // to depend on the Notebook or Pager classes.
         for (var i=0; i<l; i++) {
-            if (payload[i].source === 'page') {
-                var data = {'text':payload[i].text};
-                $([IPython.events]).trigger('open_with_text.Pager', data);
-            } else if (payload[i].source === 'set_next_input') {
-                if (callbacks.set_next_input !== undefined) {
-                    callbacks.set_next_input(payload[i].text);
-                }
+            var payload = payloads[i];
+            var callback = payload_callbacks[payload.source];
+            if (callback) {
+                callback(payload, msg);
             }
         }
     };
@@ -483,6 +497,17 @@ var IPython = (function (IPython) {
         if (execution_state === 'busy') {
             $([IPython.events]).trigger('status_busy.Kernel', {kernel: this});
         } else if (execution_state === 'idle') {
+            // clear callbacks
+            var parent_id = msg.parent_header.msg_id;
+            var callbacks = this.get_callbacks_for_msg(parent_id);
+            if (callbacks !== undefined) {
+                delete callbacks.iopub;
+                delete callbacks.input;
+                if (!callbacks.shell) {
+                    this.clear_callbacks_for_msg(parent_id);
+                }
+            }
+        
             $([IPython.events]).trigger('status_idle.Kernel', {kernel: this});
         } else if (execution_state === 'restarting') {
             // autorestarting is distinct from restarting,
@@ -501,12 +526,12 @@ var IPython = (function (IPython) {
     // handle clear_output message
     Kernel.prototype._handle_clear_output = function (msg) {
         var callbacks = this.get_callbacks_for_msg(msg.parent_header.msg_id);
-        if (callbacks === undefined) {
+        if (!callbacks || !callbacks.iopub) {
             return;
         }
-        var callback = callbacks['clear_output'];
-        if (callback !== undefined) {
-            callback(msg.content, msg.metadata);
+        var callback = callbacks.clear_output;
+        if (callback) {
+            callback(msg);
         }
     };
 
@@ -514,12 +539,12 @@ var IPython = (function (IPython) {
     // handle an output message (pyout, display_data, etc.)
     Kernel.prototype._handle_output_message = function (msg) {
         var callbacks = this.get_callbacks_for_msg(msg.parent_header.msg_id);
-        if (callbacks === undefined) {
+        if (!callbacks || !callbacks.iopub) {
             return;
         }
-        var callback = callbacks['output'];
-        if (callback !== undefined) {
-            callback(msg.header.msg_type, msg.content, msg.metadata);
+        var callback = callbacks.iopub.output;
+        if (callback) {
+            callback(msg);
         }
     };
 
@@ -546,10 +571,9 @@ var IPython = (function (IPython) {
             return;
         }
         var callbacks = this.get_callbacks_for_msg(request.parent_header.msg_id);
-        if (callbacks !== undefined) {
-            var cb = callbacks[msg_type];
-            if (cb !== undefined) {
-                cb(content, metadata);
+        if (callbacks) {
+            if (callbacks.input) {
+                callbacks.input(request);
             }
         }
     };