diff --git a/src/config/types.agent-defaults.ts b/src/config/types.agent-defaults.ts
index 24d57013667..2ec2ff014b0 100644
--- a/src/config/types.agent-defaults.ts
+++ b/src/config/types.agent-defaults.ts
@@ -299,6 +299,8 @@ export type AgentDefaultsConfig = {
     ackMaxChars?: number;
     /** Suppress tool error warning payloads during heartbeat runs. */
     suppressToolErrorWarnings?: boolean;
+    /** Run timeout in seconds for heartbeat agent turns. */
+    timeoutSeconds?: number;
     /**
      * If true, run heartbeat turns with lightweight bootstrap context.
      * Lightweight mode keeps only HEARTBEAT.md from workspace bootstrap files.
diff --git a/src/config/zod-schema.agent-runtime.ts b/src/config/zod-schema.agent-runtime.ts
index 99a83511a59..eeae09a4daa 100644
--- a/src/config/zod-schema.agent-runtime.ts
+++ b/src/config/zod-schema.agent-runtime.ts
@@ -38,6 +38,7 @@ export const HeartbeatSchema = z
     includeSystemPromptSection: z.boolean().optional(),
     ackMaxChars: z.number().int().nonnegative().optional(),
     suppressToolErrorWarnings: z.boolean().optional(),
+    timeoutSeconds: z.number().int().positive().optional(),
     lightContext: z.boolean().optional(),
     isolatedSession: z.boolean().optional(),
   })