diff --git a/index.bs b/index.bs
index 732d006..70af171 100644
--- a/index.bs
+++ b/index.bs
@@ -411,7 +411,9 @@ The <dfn>imperative execute steps</dfn>, given a {{ModelContextTool}} |tool|, a
 1. If |inputObject| [=Object type|is not an Object=] is false, then run |completionSteps| given null
    and false, and abort these steps.
 
-   Issue(#146): Specify and fire the "<code>toolactivated</code>" event.
+1. [=Fire an event=] named {{ModelContext/toolactivated}} at |targetDocument|'s [=Document/associated
+   ModelContext|associated <code>ModelContext</code>=], using {{ToolActivatedEvent}}, with its
+   {{ToolActivatedEvent/toolName}} attribute initialized to |tool|'s {{ModelContextTool/name}}.
 
 1. Let |toolPromise| be the result of [=invoke|invoking=] |tool|'s {{ModelContextTool/execute}} with
    |inputObject|.
@@ -526,6 +528,8 @@ interface ModelContext : EventTarget {
   Promise<DOMString> executeTool(RegisteredTool tool, DOMString inputArguments, optional ModelContextExecuteToolOptions options = {});
 
   attribute EventHandler ontoolchange;
+  attribute EventHandler ontoolactivated;
+  attribute EventHandler ontoolcancel;
 };
 </xmp>
 
@@ -828,6 +832,11 @@ The <dfn method for=ModelContext>executeTool(<var>tool</var>, <var>inputArgument
 
 1. [=Assert=]: |expectedTargetOrigin| is not an [=opaque origin=].
 
+1. Let |targetWindow| be |tool|'s {{RegisteredTool/window}}.
+
+1. Let |targetDocument| be |targetWindow|'s [=associated Document|associated
+   <code>Document</code>=].
+
 1. Let |promise| be [=a new promise=] created in [=this=]'s [=relevant realm=].
 
 1. If |options|'s {{ModelContextExecuteToolOptions/signal}} [=map/exists=], then:
@@ -841,15 +850,13 @@ The <dfn method for=ModelContext>executeTool(<var>tool</var>, <var>inputArgument
 
       1. [=Reject=] |promise| with |signal|'s [=AbortSignal/abort reason=].
 
-      Issue(#48): Wire up |signal| to the tool execution callback in the tool host's document, so
-      that tool abort is communicated all the way through. This should also fire the
-      "<code>toolcanceled</code>" event in the target document. See also <a
-      href=https://github.com/webmachinelearning/webmcp/issues/146>issue #146</a>.
-
-1. Let |targetWindow| be |tool|'s {{RegisteredTool/window}}.
+      1. [=Fire an event=] named {{ModelContext/toolcancel}} at |targetDocument|'s
+         [=Document/associated ModelContext|associated <code>ModelContext</code>=], using
+         {{ToolCancelEvent}}, with its {{ToolCancelEvent/toolName}} attribute initialized to
+         |tool|'s {{RegisteredTool/name}}.
 
-1. Let |targetDocument| be |targetWindow|'s [=associated Document|associated
-   <code>Document</code>=].
+      Issue(#48): Wire up |signal| to the tool execution callback in the tool host's document, so
+      that tool abort is communicated all the way through.
 
 1. Run the following steps [=in parallel=]:
 
@@ -1158,6 +1165,56 @@ dictionary RegisteredTool {
 </dl>
 
 
+<h4 id="tool-activated-event">ToolActivatedEvent Interface</h4>
+
+The {{ToolActivatedEvent}} interface represents a {{ModelContext/toolactivated}} event that is dispatched at {{ModelContext}} when a tool is invoked by an [=agent=].
+
+<xmp class="idl">
+[Exposed=Window, SecureContext]
+interface ToolActivatedEvent : Event {
+  constructor(DOMString type, optional ToolActivatedEventInit eventInitDict = {});
+  readonly attribute DOMString toolName;
+  readonly attribute Element? element;
+};
+
+dictionary ToolActivatedEventInit : EventInit {
+  DOMString toolName = "";
+  Element? element = null;
+};
+</xmp>
+
+<dl class="domintro" dfn-type=attribute dfn-for=ToolActivatedEvent>
+  : <dfn>toolName</dfn>
+  :: Returns the name of the tool that was activated.
+  : <dfn>element</dfn>
+  :: Returns the form element associated with the tool, if any.
+</dl>
+
+<h4 id="tool-cancel-event">ToolCancelEvent Interface</h4>
+
+The {{ToolCancelEvent}} interface represents a {{ModelContext/toolcancel}} event that is dispatched at {{ModelContext}} when a tool's invocation is canceled by an [=agent=].
+
+<xmp class="idl">
+[Exposed=Window, SecureContext]
+interface ToolCancelEvent : Event {
+  constructor(DOMString type, optional ToolCancelEventInit eventInitDict = {});
+  readonly attribute DOMString toolName;
+  readonly attribute Element? element;
+};
+
+dictionary ToolCancelEventInit : EventInit {
+  DOMString toolName = "";
+  Element? element = null;
+};
+</xmp>
+
+<dl class="domintro" dfn-type=attribute dfn-for=ToolCancelEvent>
+  : <dfn>toolName</dfn>
+  :: Returns the name of the tool that was canceled.
+  : <dfn>element</dfn>
+  :: Returns the form element associated with the tool, if any.
+</dl>
+
 <h3 id="declarative-api">Declarative WebMCP</h3>
 
 This section is entirely a TODO. For now, refer to the [explainer draft](https://github.com/webmachinelearning/webmcp/pull/76).
@@ -1217,6 +1274,12 @@ that must be supported, as [=event handler IDL attributes=], by all {{ModelConte
     <tr>
       <td><dfn attribute for="ModelContext">ontoolchange</dfn>
       <td><dfn event for="ModelContext">toolchange</dfn>
+    <tr>
+      <td><dfn attribute for="ModelContext">ontoolactivated</dfn>
+      <td><dfn event for="ModelContext">toolactivated</dfn>
+    <tr>
+      <td><dfn attribute for="ModelContext">ontoolcancel</dfn>
+      <td><dfn event for="ModelContext">toolcancel</dfn>
 </table>
 
 <h3 id="permissions-policy">Permissions policy integration</h3>