Cover BOM wrapper and internal BOM baseURL handling

Co-authored-by: Eric Allam <eric@trigger.dev>

.changeset/curly-radios-visit.md

@@ -10,6 +10,6 @@ Add a new `@trigger.dev/ai` package with:
 - reconnect-aware stream handling on top of Trigger.dev Realtime Streams v2
 - strict `baseURL` normalization/validation (trimming, path-safe slash handling, absolute `http(s)` URLs only, no query/hash/credentials)
 - rejection of internal whitespace characters in normalized `baseURL` values
-- rejection of internal invisible separator characters (e.g. zero-width spaces) in normalized `baseURL` values
+- rejection of internal invisible separator characters (e.g. zero-width/BOM characters) in normalized `baseURL` values
 - 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

docs/tasks/streams.mdx

@@ -668,6 +668,7 @@ Examples:
 - ✅ `  https://api.trigger.dev/custom-prefix///   ` (trimmed + normalized)
 - ✅ `https://api.trigger.dev/custom%20prefix` (percent-encoded whitespace)
 - ✅ `https://api.trigger.dev/custom%3Fprefix%23segment` (percent-encoded `?` / `#`)
+- ✅ `\uFEFFhttps://api.trigger.dev/custom-prefix/\uFEFF` (BOM wrapper trimmed)
 - ❌ `https://api.trigger.dev?foo=bar`
 - ❌ `https://api.trigger.dev#fragment`
 - ❌ `https://user:pass@api.trigger.dev`
@@ -677,6 +678,7 @@ Examples:
 - ❌ `https://api.trigger.dev/\tinternal`
 - ❌ `https://api.trigger.dev/\rinternal`
 - ❌ `https://api.trigger.dev/\u200Binternal`
+- ❌ `https://api.trigger.dev/\uFEFFinternal`
 
 Validation errors use these exact messages:
 

packages/ai/CHANGELOG.md

@@ -26,7 +26,7 @@
 - Added explicit validation that `baseURL` uses `http` or `https`.
 - Added explicit validation that `baseURL` excludes query parameters and hash fragments.
 - Added explicit validation that `baseURL` excludes username/password credentials.
-- Added explicit validation that `baseURL` excludes internal whitespace/invisible separator characters.
+- Added explicit validation that `baseURL` excludes internal whitespace/invisible separator characters (including zero-width/BOM characters).
 - 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).

packages/ai/README.md

@@ -175,6 +175,7 @@ Examples:
 - ✅ `  https://api.trigger.dev/custom-prefix///   ` (trimmed + normalized)
 - ✅ `https://api.trigger.dev/custom%20prefix` (percent-encoded whitespace)
 - ✅ `https://api.trigger.dev/custom%3Fprefix%23segment` (percent-encoded `?` / `#`)
+- ✅ `\uFEFFhttps://api.trigger.dev/custom-prefix/\uFEFF` (BOM wrapper trimmed)
 - ❌ `https://api.trigger.dev?foo=bar` (query string)
 - ❌ `https://api.trigger.dev#fragment` (hash fragment)
 - ❌ `https://user:pass@api.trigger.dev` (credentials)
@@ -184,6 +185,7 @@ Examples:
 - ❌ `https://api.trigger.dev/\tinternal` (internal tab characters)
 - ❌ `https://api.trigger.dev/\rinternal` (internal carriage-return characters)
 - ❌ `https://api.trigger.dev/\u200Binternal` (internal zero-width-space characters)
+- ❌ `https://api.trigger.dev/\uFEFFinternal` (internal BOM characters)
 
 Validation errors use these exact messages:
 

packages/ai/src/chatTransport.test.ts

@@ -764,6 +764,17 @@ describe("TriggerChatTransport", function () {
     }).toThrowError("baseURL must not contain internal whitespace characters");
   });
 
+  it("throws when baseURL contains internal BOM characters", function () {
+    expect(function () {
+      new TriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "https://api.trigger.dev/\uFEFFinternal",
+        stream: "chat-stream",
+      });
+    }).toThrowError("baseURL must not contain internal whitespace characters");
+  });
+
   it("throws when baseURL is a relative path", function () {
     expect(function () {
       new TriggerChatTransport({
@@ -1006,6 +1017,17 @@ describe("TriggerChatTransport", function () {
     }).not.toThrow();
   });
 
+  it("accepts BOM-wrapped baseURL values", function () {
+    expect(function () {
+      new TriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "\uFEFFhttps://api.trigger.dev/custom-prefix/\uFEFF",
+        stream: "chat-stream",
+      });
+    }).not.toThrow();
+  });
+
   it("accepts percent-encoded whitespace in baseURL paths", function () {
     expect(function () {
       new TriggerChatTransport({
@@ -3393,6 +3415,17 @@ describe("TriggerChatTransport", function () {
     }).toThrowError("baseURL must not contain internal whitespace characters");
   });
 
+  it("throws from factory when baseURL contains internal BOM characters", function () {
+    expect(function () {
+      createTriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "https://api.trigger.dev/\uFEFFinternal",
+        stream: "chat-stream",
+      });
+    }).toThrowError("baseURL must not contain internal whitespace characters");
+  });
+
   it("throws from factory when baseURL protocol is not http or https", function () {
     expect(function () {
       createTriggerChatTransport({
@@ -3624,6 +3657,17 @@ describe("TriggerChatTransport", function () {
     }).not.toThrow();
   });
 
+  it("accepts BOM-wrapped baseURL values from factory", function () {
+    expect(function () {
+      createTriggerChatTransport({
+        task: "chat-task",
+        accessToken: "pk_trigger",
+        baseURL: "\uFEFFhttps://api.trigger.dev/custom-prefix/\uFEFF",
+        stream: "chat-stream",
+      });
+    }).not.toThrow();
+  });
+
   it("accepts percent-encoded whitespace in baseURL paths from factory", function () {
     expect(function () {
       createTriggerChatTransport({