From daaf481b84f94a9661f2ec1afbd62f5733dd85af Mon Sep 17 00:00:00 2001
From: Olivier Chafik <ochafik@anthropic.com>
Date: Wed, 7 Jan 2026 19:29:21 +0000
Subject: [PATCH 1/2] Make ui.resourceUri optional (for tools that just need
 visibility)

---
 src/spec.types.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/spec.types.ts b/src/spec.types.ts
index 5b7135ba2..a060bfa06 100644
--- a/src/spec.types.ts
+++ b/src/spec.types.ts
@@ -549,12 +549,12 @@ export type McpUiToolVisibility = "model" | "app";
  */
 export interface McpUiToolMeta {
   /**
-   * URI of the UI resource to display for this tool.
+   * URI of the UI resource to display for this tool, if any.
    * This is converted to `_meta["ui/resourceUri"]`.
    *
    * @example "ui://weather/widget.html"
    */
-  resourceUri: string;
+  resourceUri?: string;
   /**
    * @description Who can access this tool. Default: ["model", "app"]
    * - "model": Tool visible to and callable by the agent

From 6bee5556789e5495d78791bb4e59c6065219c1c2 Mon Sep 17 00:00:00 2001
From: Olivier Chafik <ochafik@anthropic.com>
Date: Wed, 7 Jan 2026 19:34:49 +0000
Subject: [PATCH 2/2] chore: regenerate schemas for optional resourceUri

---
 src/generated/schema.json | 1 -
 src/generated/schema.ts   | 4 ++--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/generated/schema.json b/src/generated/schema.json
index 995eb4dd1..5143214a6 100644
--- a/src/generated/schema.json
+++ b/src/generated/schema.json
@@ -4047,7 +4047,6 @@
           }
         }
       },
-      "required": ["resourceUri"],
       "additionalProperties": false
     },
     "McpUiToolResultNotification": {
diff --git a/src/generated/schema.ts b/src/generated/schema.ts
index bc415e51e..bd94075e8 100644
--- a/src/generated/schema.ts
+++ b/src/generated/schema.ts
@@ -484,12 +484,12 @@ export const McpUiToolVisibilitySchema = z
  */
 export const McpUiToolMetaSchema = z.object({
   /**
-   * URI of the UI resource to display for this tool.
+   * URI of the UI resource to display for this tool, if any.
    * This is converted to `_meta["ui/resourceUri"]`.
    *
    * @example "ui://weather/widget.html"
    */
-  resourceUri: z.string(),
+  resourceUri: z.string().optional(),
   /**
    * @description Who can access this tool. Default: ["model", "app"]
    * - "model": Tool visible to and callable by the agent