diff --git a/proto/agynio/api/agents/v1/agents.proto b/proto/agynio/api/agents/v1/agents.proto
index e6dee3f..744f75e 100644
--- a/proto/agynio/api/agents/v1/agents.proto
+++ b/proto/agynio/api/agents/v1/agents.proto
@@ -301,6 +301,10 @@ message Agent {
   // Vendor model name for native mode, opaque to the platform. Mutually
   // exclusive with model, which mode the environment is in decides.
   string model_name = 19;
+  // Whether this agent's idle workloads are hibernated. Defaults to true.
+  bool hibernate = 20;
+  optional string hibernate_after = 21; // Go duration string (e.g., "0s", "30s", "5m").
+  optional string hibernation_ttl = 22; // Go duration string (e.g., "24h", "168h"). Minimum "1h".
 }
 
 message CreateAgentRequest {
@@ -325,6 +329,10 @@ message CreateAgentRequest {
   optional string instance_idle_ttl = 17; // Go duration string (e.g., "30m", "6h").
   // Required-and-exclusive against model, decided by the environment's llm_mode.
   string model_name = 18;
+  // Unset defaults to true.
+  optional bool hibernate = 19;
+  optional string hibernate_after = 20; // Go duration string (e.g., "0s", "30s", "5m").
+  optional string hibernation_ttl = 21; // Go duration string (e.g., "24h", "168h"). Minimum "1h".
 }
 
 message CreateAgentResponse {
@@ -371,6 +379,9 @@ message UpdateAgentRequest {
   optional AgentFinalMessage final_message = 16;
   optional string instance_idle_ttl = 17; // Go duration string (e.g., "30m", "6h").
   optional string model_name = 18;
+  optional bool hibernate = 19;
+  optional string hibernate_after = 20; // Go duration string (e.g., "0s", "30s", "5m").
+  optional string hibernation_ttl = 21; // Go duration string (e.g., "24h", "168h"). Minimum "1h".
 }
 
 message UpdateAgentResponse {
@@ -770,6 +781,8 @@ enum SandboxStatus {
   SANDBOX_STATUS_STOPPED = 3;
   SANDBOX_STATUS_FAILED = 4;
   SANDBOX_STATUS_TERMINATED = 5;
+  // Workload state persisted on the runner, occupying no compute.
+  SANDBOX_STATUS_HIBERNATED = 6;
 }
 
 message Sandbox {
diff --git a/proto/agynio/api/gateway/v1/runners.proto b/proto/agynio/api/gateway/v1/runners.proto
index bfe2a29..dbe5342 100644
--- a/proto/agynio/api/gateway/v1/runners.proto
+++ b/proto/agynio/api/gateway/v1/runners.proto
@@ -34,6 +34,7 @@ service RunnersGateway {
   rpc ListWorkloadsByAgentInstance(agynio.api.runners.v1.ListWorkloadsByAgentInstanceRequest) returns (agynio.api.runners.v1.ListWorkloadsByAgentInstanceResponse);
   rpc GetWorkload(agynio.api.runners.v1.GetWorkloadRequest) returns (agynio.api.runners.v1.GetWorkloadResponse);
   rpc TouchWorkload(agynio.api.runners.v1.TouchWorkloadRequest) returns (agynio.api.runners.v1.TouchWorkloadResponse);
+  rpc ReportWorkloadIdle(agynio.api.runners.v1.ReportWorkloadIdleRequest) returns (agynio.api.runners.v1.ReportWorkloadIdleResponse);
   rpc StreamWorkloadLogs(agynio.api.runner.v1.StreamWorkloadLogsRequest) returns (stream agynio.api.runner.v1.StreamWorkloadLogsResponse);
 
   // --- Volumes ---
diff --git a/proto/agynio/api/runner/v1/runner.proto b/proto/agynio/api/runner/v1/runner.proto
index 4061e6b..3e17e53 100644
--- a/proto/agynio/api/runner/v1/runner.proto
+++ b/proto/agynio/api/runner/v1/runner.proto
@@ -15,6 +15,10 @@ service RunnerService {
   rpc StopWorkload(StopWorkloadRequest) returns (StopWorkloadResponse);
   rpc RemoveWorkload(RemoveWorkloadRequest) returns (RemoveWorkloadResponse);
 
+  // Unimplemented on a runner that does not advertise the hibernate capability.
+  rpc HibernateWorkload(HibernateWorkloadRequest) returns (HibernateWorkloadResponse);
+  rpc WakeWorkload(WakeWorkloadRequest) returns (WakeWorkloadResponse);
+
   // Minimal inspect surface with EXACT fields required by platform today.
   rpc InspectWorkload(InspectWorkloadRequest) returns (InspectWorkloadResponse);
 
@@ -221,6 +225,12 @@ enum WorkloadStatus {
   WORKLOAD_STATUS_STARTING = 2;
   WORKLOAD_STATUS_STOPPED = 3;
   WORKLOAD_STATUS_FAILED = 4;
+  // Being paused and persisted by the runner.
+  WORKLOAD_STATUS_HIBERNATING = 5;
+  // State persisted on the runner, occupying no compute.
+  WORKLOAD_STATUS_HIBERNATED = 6;
+  // Being resumed from its persisted state.
+  WORKLOAD_STATUS_WAKING = 7;
 }
 
 message WorkloadFailure {
@@ -244,6 +254,20 @@ message RemoveWorkloadRequest {
 
 message RemoveWorkloadResponse {}
 
+message HibernateWorkloadRequest {
+  string workload_id = 1;
+}
+
+message HibernateWorkloadResponse {}
+
+message WakeWorkloadRequest {
+  string workload_id = 1;
+
+  repeated ImagePullCredential image_pull_credentials = 2;
+}
+
+message WakeWorkloadResponse {}
+
 enum ContainerRole {
   CONTAINER_ROLE_UNSPECIFIED = 0;
   CONTAINER_ROLE_MAIN = 1;
@@ -294,6 +318,11 @@ message InspectWorkloadResponse {
   string state_status = 7;
   bool state_running = 8;
   repeated WorkloadContainer containers = 9;
+
+  WorkloadStatus status = 10;
+
+  // Size of the persisted state in bytes. Present when status is HIBERNATED.
+  optional int64 snapshot_size_bytes = 11;
 }
 
 message TargetMount {
@@ -316,6 +345,9 @@ message ListWorkloadsRequest {}
 message WorkloadListItem {
   string instance_id = 1;
   string workload_key = 2;
+  WorkloadStatus status = 3;
+  // Size of the persisted state in bytes. Present when status is HIBERNATED.
+  optional int64 snapshot_size_bytes = 4;
 }
 
 message ListWorkloadsResponse {
diff --git a/proto/agynio/api/runners/v1/runners.proto b/proto/agynio/api/runners/v1/runners.proto
index 75b2e07..b076cfc 100644
--- a/proto/agynio/api/runners/v1/runners.proto
+++ b/proto/agynio/api/runners/v1/runners.proto
@@ -49,6 +49,7 @@ service RunnersService {
   rpc UpdateWorkloadStatus(UpdateWorkloadStatusRequest) returns (UpdateWorkloadStatusResponse);
   rpc ReportWorkloadState(ReportWorkloadStateRequest) returns (ReportWorkloadStateResponse);
   rpc TouchWorkload(TouchWorkloadRequest) returns (TouchWorkloadResponse);
+  rpc ReportWorkloadIdle(ReportWorkloadIdleRequest) returns (ReportWorkloadIdleResponse);
   rpc DeleteWorkload(DeleteWorkloadRequest) returns (DeleteWorkloadResponse);
   rpc GetWorkload(GetWorkloadRequest) returns (GetWorkloadResponse);
   rpc ListWorkloadsByThread(ListWorkloadsByThreadRequest) returns (ListWorkloadsByThreadResponse);
@@ -331,6 +332,12 @@ enum WorkloadStatus {
   WORKLOAD_STATUS_STOPPING = 3;
   WORKLOAD_STATUS_STOPPED = 4;
   WORKLOAD_STATUS_FAILED = 5;
+  // Being paused and persisted by the runner.
+  WORKLOAD_STATUS_HIBERNATING = 6;
+  // State persisted on the runner, occupying no compute.
+  WORKLOAD_STATUS_HIBERNATED = 7;
+  // Being resumed from its persisted state.
+  WORKLOAD_STATUS_WAKING = 8;
 }
 
 enum WorkloadAgentState {
@@ -346,6 +353,10 @@ enum WorkloadFailureReason {
   WORKLOAD_FAILURE_REASON_CONFIG_INVALID = 3;
   WORKLOAD_FAILURE_REASON_CRASHLOOP = 4;
   WORKLOAD_FAILURE_REASON_RUNTIME_LOST = 5;
+  // A hibernated workload could not be woken.
+  WORKLOAD_FAILURE_REASON_WAKE_FAILED = 6;
+  // A hibernated workload's persisted state is gone from its runner.
+  WORKLOAD_FAILURE_REASON_SNAPSHOT_LOST = 7;
 }
 
 enum ContainerRole {
@@ -400,6 +411,15 @@ message Workload {
   // Whether shells in this workload outlive the connections that reach them.
   // Resolved from the environment at start and fixed for the workload's life.
   bool persistent_shells = 27;
+  // When the workload most recently entered WORKLOAD_STATUS_HIBERNATED. Unset
+  // while it has never been hibernated or is awake.
+  optional google.protobuf.Timestamp hibernated_at = 28;
+  // When the workload most recently left WORKLOAD_STATUS_HIBERNATED for
+  // WORKLOAD_STATUS_RUNNING. Unset until its first wake.
+  optional google.protobuf.Timestamp woken_at = 29;
+  // Size of the persisted state in bytes. Set while status is
+  // WORKLOAD_STATUS_HIBERNATED; unset while the workload is awake.
+  optional int64 snapshot_size_bytes = 30;
   // Machine-readable reason for failures when status is WORKLOAD_STATUS_FAILED.
   // When status is not FAILED, this value may be unset or stale.
   optional WorkloadFailureReason failure_reason = 15;
@@ -460,6 +480,9 @@ message UpdateWorkloadRequest {
   optional WorkloadFailureReason failure_reason = 7;
   // Human-readable failure detail; not intended for programmatic parsing.
   optional string failure_message = 8;
+  optional google.protobuf.Timestamp hibernated_at = 9;
+  optional google.protobuf.Timestamp woken_at = 10;
+  optional int64 snapshot_size_bytes = 11;
 }
 
 message UpdateWorkloadResponse {
@@ -473,6 +496,8 @@ message ReportWorkloadStateRequest {
   WorkloadStatus status = 4;
   repeated Container containers = 5;
   google.protobuf.Timestamp observed_at = 6;
+  // Size of the persisted state in bytes. Set with WORKLOAD_STATUS_HIBERNATED.
+  optional int64 snapshot_size_bytes = 7;
 }
 
 message ReportWorkloadStateResponse {
@@ -497,6 +522,12 @@ message TouchWorkloadRequest {
 
 message TouchWorkloadResponse {}
 
+message ReportWorkloadIdleRequest {
+  string id = 1;
+}
+
+message ReportWorkloadIdleResponse {}
+
 message DeleteWorkloadRequest {
   string id = 1;
 }