diff --git a/cli/src/commands/worktree.ts b/cli/src/commands/worktree.ts
index 4f0ed887..7311793b 100644
--- a/cli/src/commands/worktree.ts
+++ b/cli/src/commands/worktree.ts
@@ -514,6 +514,7 @@ async function ensureEmbeddedPostgres(dataDir: string, preferredPort: number): P
     password: "paperclip",
     port,
     persistent: true,
+    initdbFlags: ["--encoding=UTF8", "--locale=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/packages/db/src/client.ts b/packages/db/src/client.ts
index c4275dc4..83b4aa78 100644
--- a/packages/db/src/client.ts
+++ b/packages/db/src/client.ts
@@ -730,7 +730,7 @@ export async function ensurePostgresDatabase(
     `;
     if (existing.length > 0) return "exists";
 
-    await sql.unsafe(`create database "${databaseName}"`);
+    await sql.unsafe(`create database "${databaseName}" encoding 'UTF8' lc_collate 'C' lc_ctype 'C' template template0`);
     return "created";
   } finally {
     await sql.end();
diff --git a/packages/db/src/migration-runtime.ts b/packages/db/src/migration-runtime.ts
index bc90b762..10b7b9b1 100644
--- a/packages/db/src/migration-runtime.ts
+++ b/packages/db/src/migration-runtime.ts
@@ -96,6 +96,7 @@ async function ensureEmbeddedPostgresConnection(
     password: "paperclip",
     port: preferredPort,
     persistent: true,
+    initdbFlags: ["--encoding=UTF8", "--locale=C"],
     onLog: () => {},
     onError: () => {},
   });
diff --git a/server/src/index.ts b/server/src/index.ts
index c220df92..50c6a7b2 100644
--- a/server/src/index.ts
+++ b/server/src/index.ts
@@ -334,6 +334,7 @@ export async function startServer(): Promise<StartedServer> {
         password: "paperclip",
         port,
         persistent: true,
+        initdbFlags: ["--encoding=UTF8", "--locale=C"],
         onLog: appendEmbeddedPostgresLog,
         onError: appendEmbeddedPostgresLog,
       });