diff --git a/extensions.toml b/extensions.toml
index b77fdf7a63..844cb0ed69 100644
--- a/extensions.toml
+++ b/extensions.toml
@@ -663,7 +663,7 @@ version = "1.3.3"
 
 [corust-agent]
 submodule = "extensions/corust-agent"
-version = "0.3.2"
+version = "0.3.3"
 
 [cosmos]
 submodule = "extensions/cosmos"
@@ -2192,7 +2192,7 @@ version = "1.0.3"
 
 [modest-dark]
 submodule = "extensions/modest-dark"
-version = "0.1.8"
+version = "0.1.9"
 
 [modus-themes]
 submodule = "extensions/modus-themes"
@@ -3749,6 +3749,7 @@ version = "0.1.4"
 
 [usd]
 submodule = "extensions/usd"
+version = "0.1.0"
 
 [utl]
 submodule = "extensions/utl"
diff --git a/extensions/corust-agent b/extensions/corust-agent
index 6abc293b99..f9ef70e97a 160000
--- a/extensions/corust-agent
+++ b/extensions/corust-agent
@@ -1 +1 @@
-Subproject commit 6abc293b9921650421ba0819d6ef0c1ebacb0b9c
+Subproject commit f9ef70e97a16ca7fb5911f4a96c972ef3f181e47
diff --git a/extensions/modest-dark b/extensions/modest-dark
index 7e0febea65..ffc5c22165 160000
--- a/extensions/modest-dark
+++ b/extensions/modest-dark
@@ -1 +1 @@
-Subproject commit 7e0febea65f7ebbc4b3f0ce45adc340d7e6e8738
+Subproject commit ffc5c221651685b0d9f54c067efea090fe9c5643
diff --git a/src/lib/validation.js b/src/lib/validation.js
index 9546795680..56fd7dd981 100644
--- a/src/lib/validation.js
+++ b/src/lib/validation.js
@@ -33,7 +33,7 @@ const SUBMODULE_LOCATION_EXCEPTIONS = ["extensions/zed"];
  * @param {Record<string, any>} extensionsToml
  */
 export function validateExtensionsToml(extensionsToml) {
-  for (const [extensionId, _extensionInfo] of Object.entries(extensionsToml)) {
+  for (const [extensionId, extensionInfo] of Object.entries(extensionsToml)) {
     if (!EXTENSION_ID_PATTERN.test(extensionId)) {
       throw new Error(
         `Extension IDs must only consist of lowercase letters, numbers, and hyphens ('-'): "${extensionId}".`,
@@ -57,6 +57,12 @@ export function validateExtensionsToml(extensionsToml) {
         `Extension IDs should not end with "-zed", as they are all Zed extensions: "${extensionId}".`,
       );
     }
+
+    if (!extensionInfo.submodule || !extensionInfo.version) {
+      throw new Error(
+        `Missing required field "submodule" or "version" for extension "${extensionId}"`,
+      );
+    }
   }
 }
 
diff --git a/src/lib/validation.test.js b/src/lib/validation.test.js
index 94d099bc2b..cdc90ca3e8 100644
--- a/src/lib/validation.test.js
+++ b/src/lib/validation.test.js
@@ -44,12 +44,15 @@ describe("validateManifest", () => {
 });
 
 describe("validateExtensionsToml", () => {
-  describe("when `extensions.toml` only contains extensions with valid IDs", () => {
+  describe("when `extensions.toml` only contains extensions with valid IDs and entries", () => {
     it.each(["my-cool-extension", "base16"])(
       'does not throw for "%s"',
       (extensionId) => {
         const extensionsToml = {
-          [extensionId]: {},
+          [extensionId]: {
+            submodule: "https://github.com/zed-extensions/my-extension",
+            version: "0.1.0",
+          },
         };
 
         expect(() => validateExtensionsToml(extensionsToml)).not.toThrow();
@@ -71,6 +74,34 @@ describe("validateExtensionsToml", () => {
       },
     );
   });
+
+  describe("when `extensions.toml` contains an entry with missing submodule", () => {
+    it.each(["my-cool-extension"])('does not throw for "%s"', (extensionId) => {
+      const extensionsToml = {
+        [extensionId]: {
+          version: "0.1.0",
+        },
+      };
+
+      expect(() => validateExtensionsToml(extensionsToml)).toThrowError(
+        `Missing required field "submodule" or "version" for extension "${extensionId}"`,
+      );
+    });
+  });
+
+  describe("when `extensions.toml` contains an entry with missing version", () => {
+    it.each(["my-cool-extension"])('does not throw for "%s"', (extensionId) => {
+      const extensionsToml = {
+        [extensionId]: {
+          submodule: "https://github.com/zed-extensions/my-extension",
+        },
+      };
+
+      expect(() => validateExtensionsToml(extensionsToml)).toThrowError(
+        `Missing required field "submodule" or "version" for extension "${extensionId}"`,
+      );
+    });
+  });
 });
 
 describe("validateGitmodules", () => {