From 0db76cad8300000544197646068d8edb0ac57dd5 Mon Sep 17 00:00:00 2001
From: Yifan Chen <emecii23@gmail.com>
Date: Sat, 5 Sep 2026 20:10:44 -0700
Subject: [PATCH 1/2] Remove unreachable aborted-signal check and fix two
 unparseable steps
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`registerTool()` checks the same aborted signal twice. #240 added an
early check before the `exposedTo` validation but left the original
in place inside the signal block. Between the two, the algorithm only
builds a list of origins, runs the URL parser, and creates a promise —
no step yields to the event loop or invokes author code, so the signal's
aborted flag cannot change and the second check is dead. Removing the
later one preserves #240's intent, which was to let an aborted signal
win over a `SecurityError`.

`getTools()` reads "If |toolOwnerIsRequested| be true if ...", which
binds nothing; the next step reads that variable, so the step is a
`Let`.

`registerTool()` dereferences a bare {{ModelContextTool/description}}
with no object to read it from. Every other member access in the
algorithm is written |tool|'s {{ModelContextTool/...}}. The |tool name|
half of the same step is already covered by the next step, so this
drops it rather than repeating it.
---
 index.bs | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/index.bs b/index.bs
index 46c95ea..38483d0 100644
--- a/index.bs
+++ b/index.bs
@@ -669,7 +669,7 @@ The <dfn method for=ModelContext>registerTool(<var>tool</var>, <var>options</var
 1. If |tool map|[|tool name|] [=map/exists=], then return [=a promise rejected with=] an
    {{InvalidStateError}} {{DOMException}}.
 
-1. If |tool name| or {{ModelContextTool/description}} is an empty string, then return [=a promise
+1. If |tool|'s {{ModelContextTool/description}} is the empty string, then return [=a promise
    rejected with=] an {{InvalidStateError}} {{DOMException}}.
 
 1. If either |tool name| is the empty string, or its [=string/length=] is greater than 128, or if
@@ -722,9 +722,6 @@ The <dfn method for=ModelContext>registerTool(<var>tool</var>, <var>options</var
 
    1. Let |signal| be |options|'s {{ModelContextRegisterToolOptions/signal}}.
 
-   1. If |signal| is [=AbortSignal/aborted=], then return [=a promise rejected with=]
-      |signal|'s [=AbortSignal/abort reason=].
-
    1. [=AbortSignal/add|Add the following abort steps=] to |signal|:
 
         1. [=model context/Unregister a tool=] given [=this=] and |tool name|.
@@ -833,8 +830,8 @@ The <dfn method for=ModelContext>getTools(<var>options</var>)</dfn> method steps
 
       1. Let |callerOrigin| be |toolRequestor|'s [=Document/origin=].
 
-      1. If |toolOwnerIsRequested| be true if |targetOrigin| is [=same origin=] with |callerOrigin|,
-         or if |from origins| [=list/contains=] |targetOrigin|; otherwise, false.
+      1. Let |toolOwnerIsRequested| be true if |targetOrigin| is [=same origin=] with
+         |callerOrigin|, or if |from origins| [=list/contains=] |targetOrigin|; otherwise, false.
 
       1. If |toolOwnerIsRequested| is false, then [=iteration/continue=].
 

From 63a8b3ed27275f208d9b0e9ec29cd5dc7fb975a6 Mon Sep 17 00:00:00 2001
From: Yifan Chen <emecii23@gmail.com>
Date: Fri, 11 Sep 2026 09:08:44 -0700
Subject: [PATCH 2/2] Address registerTool review feedback

---
 index.bs | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/index.bs b/index.bs
index 38483d0..9d418a4 100644
--- a/index.bs
+++ b/index.bs
@@ -669,13 +669,12 @@ The <dfn method for=ModelContext>registerTool(<var>tool</var>, <var>options</var
 1. If |tool map|[|tool name|] [=map/exists=], then return [=a promise rejected with=] an
    {{InvalidStateError}} {{DOMException}}.
 
-1. If |tool|'s {{ModelContextTool/description}} is the empty string, then return [=a promise
-   rejected with=] an {{InvalidStateError}} {{DOMException}}.
+1. If |tool name| is not a non-empty string or |tool|'s {{ModelContextTool/description}} is the
+   empty string, then return [=a promise rejected with=] an {{InvalidStateError}} {{DOMException}}.
 
-1. If either |tool name| is the empty string, or its [=string/length=] is greater than 128, or if
-   |tool name| contains a [=code point=] that is not an [=ASCII alphanumeric=], U+005F (_),
-   U+002D (-), or U+002E (.), then return [=a promise rejected with=] an {{InvalidStateError}}
-   {{DOMException}}.
+1. If |tool name|'s [=string/length=] is greater than 128, or if |tool name| contains a [=code
+   point=] that is not an [=ASCII alphanumeric=], U+005F (_), U+002D (-), or U+002E (.), then
+   return [=a promise rejected with=] an {{InvalidStateError}} {{DOMException}}.
 
 1. Let |stringified input schema| be the empty string.
 
@@ -722,6 +721,9 @@ The <dfn method for=ModelContext>registerTool(<var>tool</var>, <var>options</var
 
    1. Let |signal| be |options|'s {{ModelContextRegisterToolOptions/signal}}.
 
+   1. If |signal| is [=AbortSignal/aborted=], then return [=a promise rejected with=]
+      |signal|'s [=AbortSignal/abort reason=].
+
    1. [=AbortSignal/add|Add the following abort steps=] to |signal|:
 
         1. [=model context/Unregister a tool=] given [=this=] and |tool name|.