From 24536b0eeaf02d6ccff9b290119579c75179bd57 Mon Sep 17 00:00:00 2001
From: Dale Seo <5466341+DaleSeo@users.noreply.github.com>
Date: Sun, 8 Nov 2026 10:43:41 -0500
Subject: [PATCH] fix(server): send skill text with NUL bytes as a blob

---
 .../rmcp/src/handler/server/skill_catalog.rs  |  3 ++-
 crates/rmcp/tests/test_skill_catalog.rs       | 21 +++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/crates/rmcp/src/handler/server/skill_catalog.rs b/crates/rmcp/src/handler/server/skill_catalog.rs
index 0201fb26d..7c20a2792 100644
--- a/crates/rmcp/src/handler/server/skill_catalog.rs
+++ b/crates/rmcp/src/handler/server/skill_catalog.rs
@@ -215,7 +215,8 @@ impl SkillCatalog {
             .mime_type
             .is_some_and(is_textual)
             .then(|| std::str::from_utf8(&file.bytes).ok())
-            .flatten();
+            .flatten()
+            .filter(|text| !text.contains('\0'));
         let contents = match text {
             Some(text) => ResourceContents::text(text, uri),
             None => ResourceContents::blob(BASE64_STANDARD.encode(&file.bytes), uri),
diff --git a/crates/rmcp/tests/test_skill_catalog.rs b/crates/rmcp/tests/test_skill_catalog.rs
index b4c4f8423..fc8831467 100644
--- a/crates/rmcp/tests/test_skill_catalog.rs
+++ b/crates/rmcp/tests/test_skill_catalog.rs
@@ -332,6 +332,27 @@ mod serving {
         ));
     }
 
+    #[test]
+    fn should_serve_a_text_type_containing_nul_as_a_blob() {
+        let dir = skills_tree();
+        let utf16le: Vec<u8> = "<a/>".bytes().flat_map(|b| [b, 0]).collect();
+        write(dir.path(), "pdf-processing/form.xml", &utf16le);
+        let catalog = load(&dir);
+
+        let result = catalog
+            .read_resource("skill://pdf-processing/form.xml")
+            .expect("served");
+
+        assert!(matches!(
+            &result.contents[0],
+            ResourceContents::BlobResourceContents { mime_type: Some(mime), .. } if mime == "application/xml"
+        ));
+        assert_eq!(
+            read_bytes(&catalog, "skill://pdf-processing/form.xml"),
+            utf16le
+        );
+    }
+
     #[test]
     fn should_omit_the_mime_type_of_an_unknown_extension() {
         let dir = skills_tree();