diff --git a/index.bs b/index.bs
index fee1a880..da4707bb 100644
--- a/index.bs
+++ b/index.bs
@@ -72,6 +72,12 @@ urlPrefix: https://tc39.es/ecma262/; spec: ecmascript
 urlPrefix: https://tc39.es/proposal-resizablearraybuffer/; spec: RESIZABLE-BUFFERS-PROPOSAL
     type: abstract-op
         text: IsResizableArrayBuffer; url: sec-isresizablearraybuffer
+urlPrefix: https://tc39.es/proposal-async-context/; spec: ASYNC-CONTEXT-PROPOSAL
+    type: abstract-op
+        text: AsyncContextSnapshot; url: sec-asynccontextsnapshot
+        text: AsyncContextSwap; url: sec-asynccontextswap
+    type: dfn
+        text: async context mapping records; url: sec-asynccontext-mapping-record-specification-type
 </pre>
 
 <style>
@@ -6013,8 +6019,9 @@ about the execution context at the time the language binding specific object ref
 converted to an IDL value.
 
 Note: For ECMAScript objects, the [=callback context=] is used to hold a reference to the
-<a spec="HTML">incumbent settings object</a> at the time the Object value is converted to an IDL
-callback interface type value. See [[#es-callback-interface]].
+<a spec="HTML">incumbent settings object</a> and the [=list=] of [=Async Context Mapping Records=]
+at the time the Object value is converted to an IDL callback interface type value.
+See [[#es-callback-interface]].
 
 There is no way to represent a constant object reference value for a particular
 [=callback interface type=] in IDL.
@@ -6061,10 +6068,10 @@ the [=callback function=], the values can be references to objects that are not
 An IDL value of the callback function type is represented by a tuple of an object
 reference and a [=callback context=].
 
-Note: As with [=callback interface types=], the [=callback context=] is used to hold a
-reference to the <a spec="HTML">incumbent settings object</a> at
-the time an ECMAScript Object value is converted to an IDL
-callback function type value.  See [[#es-callback-function]].
+Note: As with [=callback interface types=], the [=callback context=] is used to hold a reference to
+the <a spec="HTML">incumbent settings object</a> and the [=list=] of [=Async Context Mapping
+Records=] at the time the Object value is converted to an IDL callback function type value.
+See [[#es-callback-function]].
 
 There is no way to represent a constant [=callback function=]
 value in IDL.
@@ -7671,8 +7678,10 @@ values are represented by ECMAScript Object values (including [=function objects
     to an IDL [=callback interface type=] value by running the following algorithm:
 
     1.  If <a abstract-op>Type</a>(|V|) is not Object, then [=ECMAScript/throw=] a <l spec=ecmascript>{{TypeError}}</l>.
+    1.  Let |incumbent| be the <a spec="HTML">incumbent settings object</a>.
+    1.  Let |context| be [$AsyncContextSnapshot$]().
     1.  Return the IDL [=callback interface type=] value that represents a reference to |V|, with
-        the <a spec="HTML">incumbent settings object</a> as the [=callback context=].
+        (|incumbent|, |context|) as the [=callback context=].
 </div>
 
 <p id="callback-interface-to-es">
@@ -7792,9 +7801,11 @@ IDL [=callback function types=] are represented by ECMAScript [=function objects
         [=callback function=]
         that is annotated with [{{LegacyTreatNonObjectAsNull}}],
         then [=ECMAScript/throw=] a <l spec=ecmascript>{{TypeError}}</l>.
+    1.  Let |incumbent| be the <a spec="HTML">incumbent settings object</a>.
+    1.  Let |context| be [$AsyncContextSnapshot$]().
     1.  Return the IDL [=callback function type=] value
-        that represents a reference to the same object that |V| represents, with the
-        <a spec="HTML">incumbent settings object</a> as the [=callback context=].
+        that represents a reference to the same object that |V| represents, with
+        (|incumbent|, |context|) as the [=callback context=].
 </div>
 
 <p id="callback-function-to-es">
@@ -14149,17 +14160,20 @@ the special value “missing”, which represents a missing optional argument.
 
     To <dfn id="call-a-user-objects-operation" export>call a user object's operation</dfn>,
     given a [=callback interface type=] value |value|,
-    operation name |opName|, [=Web IDL arguments list=] |args|, and optional
-    <dfn id="dfn-callback-this-value" export>callback this value</dfn> |thisArg|,
-    perform the following steps.
+    operation name |opName|, [=Web IDL arguments list=] |args|, optional
+    <dfn id="dfn-callback-this-value" export>callback this value</dfn> |thisArg|, and
+    an optional [=boolean=] |useCreationTimeAsyncContext|, perform the following steps.
     These steps will either return an IDL value or throw an exception.
 
+    1.  If |useCreationTimeAsyncContext| was not given, let |useCreationTimeAsyncContext| be false.
     1.  Let |completion| be an uninitialized variable.
     1.  If |thisArg| was not given, let |thisArg| be <emu-val>undefined</emu-val>.
     1.  Let |O| be the ECMAScript object corresponding to |value|.
     1.  Let |realm| be |O|'s [=associated realm=].
     1.  Let |relevant settings| be |realm|'s [=realm/settings object=].
-    1.  Let |stored settings| be |value|'s [=callback context=].
+    1.  Let (|stored settings|, |async context mapping|) be |value|'s [=callback context=].
+    1.  If |useCreationTimeAsyncContext| is true, then:
+         1.  Let |previous async context mapping| be [$AsyncContextSwap$](|async context mapping|).
     1.  [=Prepare to run script=] with |relevant settings|.
     1.  [=Prepare to run a callback=] with |stored settings|.
     1.  Let |X| be |O|.
@@ -14188,6 +14202,8 @@ the special value “missing”, which represents a missing optional argument.
         point |completion| will be set to an IDL value or an [=abrupt completion=].
         1.  [=Clean up after running a callback=] with |stored settings|.
         1.  [=Clean up after running script=] with |relevant settings|.
+        1.  If |useCreationTimeAsyncContext| is true, then:
+            1.  [$AsyncContextSwap$](|previous async context mapping|).
         1.  If |completion| is an IDL value, return |completion|.
         1.  If |completion| is an [=abrupt completion=] and the operation has a [=return type=]
             that is <em>not</em> a [=promise type=], throw |completion|.\[[Value]].
@@ -14245,12 +14261,13 @@ described in the previous section).
 
     To <dfn id="invoke-a-callback-function" export>invoke</dfn> a
     [=callback function type=] value |callable| with a [=Web IDL arguments list=] |args|
-    and an optional [=callback this value|callback this value=] |thisArg|,
-    perform the following steps.
+    and an optional [=callback this value|callback this value=] |thisArg|, and
+    an optional [=boolean=] |useCreationTimeAsyncContext|, perform the following steps.
     These steps will either return an IDL value or throw an exception.
 
     1.  Let |completion| be an uninitialized variable.
     1.  If |thisArg| was not given, let |thisArg| be <emu-val>undefined</emu-val>.
+    1.  If |useCreationTimeAsyncContext| was not given, let |useCreationTimeAsyncContext| be false.
     1.  Let |F| be the ECMAScript object corresponding to |callable|.
     1.  If <a abstract-op>IsCallable</a>(|F|) is <emu-val>false</emu-val>:
         1.  Note: This is only possible when the [=callback function=] came from an attribute
@@ -14259,7 +14276,9 @@ described in the previous section).
             <emu-val>undefined</emu-val> to the callback function's return type.
     1.  Let |realm| be |F|'s [=associated realm=].
     1.  Let |relevant settings| be |realm|'s [=realm/settings object=].
-    1.  Let |stored settings| be |callable|'s [=callback context=].
+    1.  Let (|stored settings|, |async context mapping|) be |callable|'s [=callback context=].
+    1.  If |useCreationTimeAsyncContext| is true, then:
+         1.  Let |previous async context mapping| be [$AsyncContextSwap$](|async context mapping|).
     1.  [=Prepare to run script=] with |relevant settings|.
     1.  [=Prepare to run a callback=] with |stored settings|.
     1.  Let |esArgs| be the result of [=Web IDL arguments list/converting=] |args| to an ECMAScript
@@ -14277,6 +14296,8 @@ described in the previous section).
         point |completion| will be set to an IDL value or an [=abrupt completion=].
         1.  [=Clean up after running a callback=] with |stored settings|.
         1.  [=Clean up after running script=] with |relevant settings|.
+        1.  If |useCreationTimeAsyncContext| is true, then:
+            1.  [$AsyncContextSwap$](|previous async context mapping|).
         1.  If |completion| is an IDL value, return |completion|.
         1.  If |completion| is an [=abrupt completion=] and the callback function has a
             [=return type=] that is <em>not</em> a [=promise type=], throw |completion|.\[[Value]].
@@ -14292,17 +14313,20 @@ a return type that is a [=promise type=].
 <div algorithm>
 
     To <dfn id="construct-a-callback-function" export>construct</dfn> a
-    [=callback function type=] value |callable| with a [=Web IDL arguments list=] |args|,
-    perform the following steps.
+    [=callback function type=] value |callable| with a [=Web IDL arguments list=] |args|, and
+    an optional [=boolean=] |useCreationTimeAsyncContext|, perform the following steps.
     These steps will either return an IDL value or throw an exception.
 
+    1.  If |useCreationTimeAsyncContext| was not given, let |useCreationTimeAsyncContext| be false.
     1.  Let |completion| be an uninitialized variable.
     1.  Let |F| be the ECMAScript object corresponding to |callable|.
     1.  If <a abstract-op>IsConstructor</a>(|F|) is <emu-val>false</emu-val>, throw a
         <l spec=ecmascript>{{TypeError}}</l> exception.
     1.  Let |realm| be |F|'s [=associated realm=].
     1.  Let |relevant settings| be |realm|'s [=realm/settings object=].
-    1.  Let |stored settings| be |callable|'s [=callback context=].
+    1.  Let (|stored settings|, |async context mapping|) be |callable|'s [=callback context=].
+    1.  If |useCreationTimeAsyncContext| is true, then:
+         1.  Let |previous async context mapping| be [$AsyncContextSwap$](|async context mapping|).
     1.  [=Prepare to run script=] with |relevant settings|.
     1.  [=Prepare to run a callback=] with |stored settings|.
     1.  Let |esArgs| be the result of [=Web IDL arguments list/converting=] |args| to an ECMAScript
@@ -14320,6 +14344,8 @@ a return type that is a [=promise type=].
         point |completion| will be set to an IDL value or an [=abrupt completion=].
         1.  [=Clean up after running a callback=] with |stored settings|.
         1.  [=Clean up after running script=] with |relevant settings|.
+        1.  If |useCreationTimeAsyncContext| is true, then:
+            1.  [$AsyncContextSwap$](|previous async context mapping|).
         1.  If |completion| is an [=abrupt completion=], throw |completion|.\[[Value]].
         1.  Return |completion|.
 </div>