diff --git a/migrations/018_chat_histories.sql b/migrations/018_chat_histories.sql
index fbe3b28..b9836e7 100644
--- a/migrations/018_chat_histories.sql
+++ b/migrations/018_chat_histories.sql
@@ -7,7 +7,7 @@ CREATE TABLE IF NOT EXISTS chat_histories (
     title       TEXT,
     channel     TEXT,
     agent_id    TEXT,
-    project_id  UUID        REFERENCES projects(id) ON DELETE SET NULL,
+    project_id  UUID        REFERENCES projects(guid) ON DELETE SET NULL,
     messages    JSONB       NOT NULL DEFAULT '[]',
     summary     TEXT,
     metadata    JSONB       NOT NULL DEFAULT '{}',