diff --git a/.changeset/curly-radios-visit.md b/.changeset/curly-radios-visit.md
index c578c8550..30833180e 100644
--- a/.changeset/curly-radios-visit.md
+++ b/.changeset/curly-radios-visit.md
@@ -16,5 +16,7 @@ Add a new `@trigger.dev/ai` package with:
   values that normalize to empty after trimming
 - expanded unicode whitespace handling coverage to include figure space (`\u2007`) and medium
   mathematical space (`\u205F`) for both wrapper trimming and internal-whitespace rejection
+- expanded invisible-separator rejection coverage to include mongolian vowel separator (`\u180E`)
+  in both wrapper and internal `baseURL` positions
 - deterministic baseURL validation error ordering for multi-issue inputs (internal whitespace → protocol → query/hash → credentials)
 - explicit default `baseURL` behavior (`https://api.trigger.dev`) and case-insensitive `HTTP(S)` protocol acceptance
diff --git a/docs/tasks/streams.mdx b/docs/tasks/streams.mdx
index 791ee48b2..59cd34ad1 100644
--- a/docs/tasks/streams.mdx
+++ b/docs/tasks/streams.mdx
@@ -679,6 +679,7 @@ Examples:
 - ❌ `\u200Bhttps://api.trigger.dev/custom-prefix/\u200B` (zero-width-space wrappers are rejected)
 - ❌ `\u200Chttps://api.trigger.dev/custom-prefix/\u200C` (zero-width-non-joiner wrappers are rejected)
 - ❌ `\u200Dhttps://api.trigger.dev/custom-prefix/\u200D` (zero-width-joiner wrappers are rejected)
+- ❌ `\u180Ehttps://api.trigger.dev/custom-prefix/\u180E` (mongolian-vowel-separator wrappers are rejected)
 - ❌ `https://api.trigger.dev?foo=bar`
 - ❌ `https://api.trigger.dev#fragment`
 - ❌ `https://user:pass@api.trigger.dev`
@@ -705,6 +706,7 @@ Examples:
 - ❌ `https://api.trigger.dev/\u2007internal`
 - ❌ `https://api.trigger.dev/\u202Finternal`
 - ❌ `https://api.trigger.dev/\u205Finternal`
+- ❌ `https://api.trigger.dev/\u180Einternal`
 - ❌ `https://api.trigger.dev/\u3000internal`
 - ❌ `https://api.trigger.dev/\u2028internal`
 - ❌ `https://api.trigger.dev/\u2029internal`
diff --git a/packages/ai/CHANGELOG.md b/packages/ai/CHANGELOG.md
index deade890e..0a05e3529 100644
--- a/packages/ai/CHANGELOG.md
+++ b/packages/ai/CHANGELOG.md
@@ -32,6 +32,8 @@
   confirmed empty-after-trim values still throw `baseURL must not be empty`.
 - Expanded unicode whitespace coverage with `\u2007` (figure space) and `\u205F` (medium mathematical space)
   across internal-whitespace rejection, wrapper trimming acceptance, and empty-after-trim validation.
+- Expanded invisible-separator coverage to reject `\u180E` (mongolian vowel separator) in both
+  internal and wrapper `baseURL` positions.
 - Documented that `HTTP://` and `HTTPS://` are accepted (case-insensitive protocol matching).
 - Added deterministic validation ordering for multi-issue baseURL values
   (internal whitespace → protocol → query/hash → credentials).
diff --git a/packages/ai/README.md b/packages/ai/README.md
index b0aba5a09..d9648515e 100644
--- a/packages/ai/README.md
+++ b/packages/ai/README.md
@@ -186,6 +186,7 @@ Examples:
 - ❌ `\u200Bhttps://api.trigger.dev/custom-prefix/\u200B` (zero-width-space wrappers are rejected)
 - ❌ `\u200Chttps://api.trigger.dev/custom-prefix/\u200C` (zero-width-non-joiner wrappers are rejected)
 - ❌ `\u200Dhttps://api.trigger.dev/custom-prefix/\u200D` (zero-width-joiner wrappers are rejected)
+- ❌ `\u180Ehttps://api.trigger.dev/custom-prefix/\u180E` (mongolian-vowel-separator wrappers are rejected)
 - ❌ `https://api.trigger.dev?foo=bar` (query string)
 - ❌ `https://api.trigger.dev#fragment` (hash fragment)
 - ❌ `https://user:pass@api.trigger.dev` (credentials)
@@ -212,6 +213,7 @@ Examples:
 - ❌ `https://api.trigger.dev/\u2007internal` (internal figure-space characters)
 - ❌ `https://api.trigger.dev/\u202Finternal` (internal narrow no-break space characters)
 - ❌ `https://api.trigger.dev/\u205Finternal` (internal medium-mathematical-space characters)
+- ❌ `https://api.trigger.dev/\u180Einternal` (internal mongolian-vowel-separator characters)
 - ❌ `https://api.trigger.dev/\u3000internal` (internal ideographic-space characters)
 - ❌ `https://api.trigger.dev/\u2028internal` (internal line-separator characters)
 - ❌ `https://api.trigger.dev/\u2029internal` (internal paragraph-separator characters)
diff --git a/packages/ai/src/chatTransport.test.ts b/packages/ai/src/chatTransport.test.ts
index 209a33f7c..19d7eb836 100644
--- a/packages/ai/src/chatTransport.test.ts
+++ b/packages/ai/src/chatTransport.test.ts
@@ -950,6 +950,17 @@ describe("TriggerChatTransport", function () {
     }).toThrowError("baseURL must not contain internal whitespace characters");
   });
 
+  it("throws when baseURL contains internal mongolian-vowel-separator characters", function () {
+    expect(function () {
+      new TriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "https://api.trigger.dev/\u180Einternal",
+        stream: "chat-stream",
+      });
+    }).toThrowError("baseURL must not contain internal whitespace characters");
+  });
+
   it("throws when baseURL contains internal line-separator characters", function () {
     expect(function () {
       new TriggerChatTransport({
@@ -1027,6 +1038,17 @@ describe("TriggerChatTransport", function () {
     }).toThrowError("baseURL must not contain internal whitespace characters");
   });
 
+  it("throws when baseURL is wrapped with mongolian-vowel-separator characters", function () {
+    expect(function () {
+      new TriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "\u180Ehttps://api.trigger.dev/custom-prefix/\u180E",
+        stream: "chat-stream",
+      });
+    }).toThrowError("baseURL must not contain internal whitespace characters");
+  });
+
   it("throws when baseURL contains internal zero-width-non-joiner characters", function () {
     expect(function () {
       new TriggerChatTransport({
@@ -4043,6 +4065,17 @@ describe("TriggerChatTransport", function () {
     }).toThrowError("baseURL must not contain internal whitespace characters");
   });
 
+  it("throws from factory when baseURL contains internal mongolian-vowel-separator characters", function () {
+    expect(function () {
+      createTriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "https://api.trigger.dev/\u180Einternal",
+        stream: "chat-stream",
+      });
+    }).toThrowError("baseURL must not contain internal whitespace characters");
+  });
+
   it("throws from factory when baseURL contains internal line-separator characters", function () {
     expect(function () {
       createTriggerChatTransport({
@@ -4120,6 +4153,17 @@ describe("TriggerChatTransport", function () {
     }).toThrowError("baseURL must not contain internal whitespace characters");
   });
 
+  it("throws from factory when baseURL is wrapped with mongolian-vowel-separator characters", function () {
+    expect(function () {
+      createTriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "\u180Ehttps://api.trigger.dev/custom-prefix/\u180E",
+        stream: "chat-stream",
+      });
+    }).toThrowError("baseURL must not contain internal whitespace characters");
+  });
+
   it("throws from factory when baseURL contains internal zero-width-non-joiner characters", function () {
     expect(function () {
       createTriggerChatTransport({
diff --git a/packages/ai/src/chatTransport.ts b/packages/ai/src/chatTransport.ts
index 7e96d1e96..98922e4e9 100644
--- a/packages/ai/src/chatTransport.ts
+++ b/packages/ai/src/chatTransport.ts
@@ -459,7 +459,7 @@ const BASE_URL_VALIDATION_ERRORS = {
 
 // Includes standard whitespace plus common invisible separator/control marks
 // that can make URLs look valid while behaving unexpectedly.
-const INTERNAL_WHITESPACE_REGEX = /[\s\u200B\u200C\u200D\u2060\uFEFF]/u;
+const INTERNAL_WHITESPACE_REGEX = /[\s\u180E\u200B\u200C\u200D\u2060\uFEFF]/u;
 
 function resolvePayloadMapper<
   UI_MESSAGE extends UIMessage,