diff --git a/src/discord.rs b/src/discord.rs
index 0311b898..278d3bf1 100644
--- a/src/discord.rs
+++ b/src/discord.rs
@@ -821,9 +821,11 @@ fn resolve_mentions(content: &str, bot_id: UserId, mentions: &[User]) -> String
 }
 
 fn shorten_thread_name(prompt: &str) -> String {
+    // Strip @(role) and @(user) placeholders left by resolve_mentions()
+    let cleaned = prompt.replace("@(role)", "").replace("@(user)", "");
     // Shorten GitHub URLs: https://github.com/owner/repo/issues/123 → owner/repo#123
     let re = regex::Regex::new(r"https?://github\.com/([^/]+/[^/]+)/(issues|pull)/(\d+)").unwrap();
-    let shortened = re.replace_all(prompt, "$1#$3");
+    let shortened = re.replace_all(cleaned.trim(), "$1#$3");
     let name: String = shortened.chars().take(40).collect();
     if name.len() < shortened.len() {
         format!("{name}...")