diff --git a/src/oplog/heads.js b/src/oplog/heads.js
index 353ae51..f9cb23e 100644
--- a/src/oplog/heads.js
+++ b/src/oplog/heads.js
@@ -25,6 +25,8 @@ const Heads = async ({ storage, heads }) => {
     }
     const newHeads = findHeads([...currentHeads, head])
     await set(newHeads)
+
+    return newHeads
   }
 
   const iterator = async function * () {
diff --git a/src/oplog/log.js b/src/oplog/log.js
index 354140b..a8351a2 100644
--- a/src/oplog/log.js
+++ b/src/oplog/log.js
@@ -222,8 +222,14 @@ const Log = async (identity, { logId, logHeads, access, entryStorage, headsStora
     if (!isValid) {
       throw new Error(`Could not validate signature for entry "${entry.hash}"`)
     }
+
     // Add the new entry to heads (union with current heads)
-    await _heads.add(entry)
+    const newHeads = await _heads.add(entry)
+
+    if (!newHeads) {
+      return false
+    }
+
     // Add the new entry to the entry storage
     await _entries.put(entry.hash, entry.bytes)
     // Add the new entry to the entry index