diff --git a/packages/agents/src/runtime/agent-os.ts b/packages/agents/src/runtime/agent-os.ts
index 3c44b72..131c50a 100644
--- a/packages/agents/src/runtime/agent-os.ts
+++ b/packages/agents/src/runtime/agent-os.ts
@@ -80,9 +80,10 @@ export const executeAgentOsAttempt = async (
       decodeWorkAttemptExecutionInput(rawInput)
     );
     const env = parseAgentEnv(process.env);
+    const endpoint = env.RIVET_PUBLIC_ENDPOINT ?? env.RIVET_ENDPOINT;
     const client = createClient<typeof runtimeRegistry>({
       disableMetadataLookup: true,
-      endpoint: env.RIVET_PUBLIC_ENDPOINT ?? env.RIVET_ENDPOINT,
+      ...(endpoint ? { endpoint } : {}),
     });
     const vm = client.workspace.getOrCreate([input.workspaceKey], {
       params: { token: env.RIVET_WORKSPACE_TOKEN },
@@ -243,9 +244,10 @@ export const cancelAgentOsAttempt = async (
   attemptId: string
 ) => {
   const env = parseAgentEnv(process.env);
+  const endpoint = env.RIVET_PUBLIC_ENDPOINT ?? env.RIVET_ENDPOINT;
   const client = createClient<typeof runtimeRegistry>({
     disableMetadataLookup: true,
-    endpoint: env.RIVET_PUBLIC_ENDPOINT ?? env.RIVET_ENDPOINT,
+    ...(endpoint ? { endpoint } : {}),
   });
   await client.workspace
     .getOrCreate([workspaceKey], {
diff --git a/packages/env/src/agent.ts b/packages/env/src/agent.ts
index e93d96b..648ce08 100644
--- a/packages/env/src/agent.ts
+++ b/packages/env/src/agent.ts
@@ -14,8 +14,14 @@ const agentEnvSchema = z.object({
   GITEA_TOKEN: z.string().min(1).optional(),
   GITEA_URL: z.url().default("https://git.openputer.com"),
   OPENROUTER_API_KEY: z.string().min(1).optional(),
-  RIVET_ENDPOINT: z.url(),
-  RIVET_PUBLIC_ENDPOINT: z.url().optional(),
+  RIVET_ENDPOINT: z.preprocess(
+    (value) => (value === "" ? undefined : value),
+    z.url().optional()
+  ),
+  RIVET_PUBLIC_ENDPOINT: z.preprocess(
+    (value) => (value === "" ? undefined : value),
+    z.url().optional()
+  ),
   RIVET_WORKSPACE_TOKEN: z.string().min(32),
   ZOPU_SOURCE_REPOSITORY: z.string().min(1).default("/opt/zopu-source"),
 });