diff --git a/poc-memory/src/transcript.rs b/poc-memory/src/transcript.rs
index 01a1fc6..beaf08a 100644
--- a/poc-memory/src/transcript.rs
+++ b/poc-memory/src/transcript.rs
@@ -203,13 +203,19 @@ impl Iterator for TailMessages {
 
             let obj_bytes = &self.mmap[open..=close];
 
+            // Quick byte check: skip objects that aren't user/assistant
+            // messages. Avoids serde-parsing megabyte tool_result objects.
+            let is_user = memchr::memmem::find(obj_bytes, b"\"type\":\"user\"").is_some();
+            let is_assistant = !is_user
+                && memchr::memmem::find(obj_bytes, b"\"type\":\"assistant\"").is_some();
+            if !is_user && !is_assistant { continue; }
+
             let obj: Value = match serde_json::from_slice(obj_bytes) {
                 Ok(v) => v,
                 Err(_) => continue,
             };
 
-            let msg_type = obj.get("type").and_then(|v| v.as_str()).unwrap_or("");
-            if msg_type != "user" && msg_type != "assistant" { continue; }
+            let msg_type = if is_user { "user" } else { "assistant" };
 
             let msg = obj.get("message").unwrap_or(&obj);
             let text = match msg.get("content") {