diff --git a/codex-rs/app-server-protocol/src/export.rs b/codex-rs/app-server-protocol/src/export.rs
index fe563a9362..bdfaa48f75 100644
--- a/codex-rs/app-server-protocol/src/export.rs
+++ b/codex-rs/app-server-protocol/src/export.rs
@@ -36,7 +36,7 @@ use std::thread;
 use std::time::Instant;
 use ts_rs::TS;
 
-const HEADER: &str = "// GENERATED CODE! DO NOT MODIFY BY HAND!\n\n";
+pub(crate) const GENERATED_TS_HEADER: &str = "// GENERATED CODE! DO NOT MODIFY BY HAND!\n\n";
 const IGNORED_DEFINITIONS: &[&str] = &["Option<()>"];
 const JSON_V1_ALLOWLIST: &[&str] = &["InitializeParams", "InitializeResponse"];
 const SPECIAL_DEFINITIONS: &[&str] = &[
@@ -1835,13 +1835,13 @@ fn prepend_header_if_missing(path: &Path) -> Result<()> {
             .with_context(|| format!("Failed to read {}", path.display()))?;
     }
 
-    if content.starts_with(HEADER) {
+    if content.starts_with(GENERATED_TS_HEADER) {
         return Ok(());
     }
 
     let mut f = fs::File::create(path)
         .with_context(|| format!("Failed to open {} for writing", path.display()))?;
-    f.write_all(HEADER.as_bytes())
+    f.write_all(GENERATED_TS_HEADER.as_bytes())
         .with_context(|| format!("Failed to write header to {}", path.display()))?;
     f.write_all(content.as_bytes())
         .with_context(|| format!("Failed to write content to {}", path.display()))?;
@@ -1909,9 +1909,10 @@ fn generate_index_ts(out_dir: &Path) -> Result<PathBuf> {
         entries.push("export * as v2 from \"./v2\";\n".to_string());
     }
 
-    let mut content =
-        String::with_capacity(HEADER.len() + entries.iter().map(String::len).sum::<usize>());
-    content.push_str(HEADER);
+    let mut content = String::with_capacity(
+        GENERATED_TS_HEADER.len() + entries.iter().map(String::len).sum::<usize>(),
+    );
+    content.push_str(GENERATED_TS_HEADER);
     for line in &entries {
         content.push_str(line);
     }
diff --git a/codex-rs/app-server-protocol/src/schema_fixtures.rs b/codex-rs/app-server-protocol/src/schema_fixtures.rs
index dcd84b5315..36dcf7402c 100644
--- a/codex-rs/app-server-protocol/src/schema_fixtures.rs
+++ b/codex-rs/app-server-protocol/src/schema_fixtures.rs
@@ -1,3 +1,4 @@
+use crate::export::GENERATED_TS_HEADER;
 use anyhow::Context;
 use anyhow::Result;
 use serde_json::Map;
@@ -95,6 +96,12 @@ fn read_file_bytes(path: &Path) -> Result<Vec<u8>> {
         let text = String::from_utf8(bytes)
             .with_context(|| format!("expected UTF-8 TypeScript in {}", path.display()))?;
         let text = text.replace("\r\n", "\n").replace('\r', "\n");
+        // Fixture comparisons care about schema content, not whether the generator
+        // re-prepended the standard banner to every TypeScript file.
+        let text = text
+            .strip_prefix(GENERATED_TS_HEADER)
+            .unwrap_or(&text)
+            .to_string();
         return Ok(text.into_bytes());
     }
     Ok(bytes)
diff --git a/codex-rs/app-server-protocol/tests/schema_fixtures.rs b/codex-rs/app-server-protocol/tests/schema_fixtures.rs
index a82488e208..9e40005886 100644
--- a/codex-rs/app-server-protocol/tests/schema_fixtures.rs
+++ b/codex-rs/app-server-protocol/tests/schema_fixtures.rs
@@ -13,7 +13,14 @@ use std::time::Instant;
 #[test]
 fn typescript_schema_fixtures_match_generated() -> Result<()> {
     assert_schema_fixtures_match_generated("typescript", |output_dir| {
-        generate_ts_with_options(output_dir, None, GenerateTsOptions::default())
+        generate_ts_with_options(
+            output_dir,
+            None,
+            GenerateTsOptions {
+                ensure_headers: false,
+                ..GenerateTsOptions::default()
+            },
+        )
     })
 }