diff --git a/crates/core/src/agent/state.rs b/crates/core/src/agent/state.rs
index a5f7f19b6b..458fe7db72 100644
--- a/crates/core/src/agent/state.rs
+++ b/crates/core/src/agent/state.rs
@@ -266,22 +266,28 @@ fn reduce_commit_entry(
     let action = action_wrapper.action();
     let (entry, maybe_link_update_delete, provenances) = unwrap_to!(action => Action::Commit);
 
-    let result = create_new_chain_header(
-        &entry,
-        agent_state,
-        &StateWrapper::from(root_state.clone()),
-        &maybe_link_update_delete,
-        provenances,
-    )
-    .and_then(|chain_header| {
-        agent_state.chain_store.add(entry)?;
-        agent_state.chain_store.add(&chain_header)?;
-        Ok((chain_header, entry.address()))
-    })
-    .and_then(|(chain_header, address)| {
-        agent_state.top_chain_header = Some(chain_header);
-        Ok(address)
-    });
+    // Only make a new header and link it if the entry isn't already in the chain
+    let entry_addres = entry.address();
+    let result = match agent_state.chain_store().contains(&entry_addres) {
+        Ok(false) => create_new_chain_header(
+            &entry,
+            agent_state,
+            &StateWrapper::from(root_state.clone()),
+            &maybe_link_update_delete,
+            provenances,
+        )
+        .and_then(|chain_header| {
+            agent_state.chain_store.add(entry)?;
+            agent_state.chain_store.add(&chain_header)?;
+            Ok(chain_header)
+        })
+        .and_then(|chain_header| {
+            agent_state.top_chain_header = Some(chain_header);
+            Ok(entry_addres)
+        }),
+        Ok(true) => Ok(entry_addres),
+        Err(e) => Err(e),
+    };
 
     agent_state.actions.insert(
         action_wrapper.clone(),