diff --git a/proto/agynio/api/agents/v1/agents.proto b/proto/agynio/api/agents/v1/agents.proto
index 3b7082c..6cc96df 100644
--- a/proto/agynio/api/agents/v1/agents.proto
+++ b/proto/agynio/api/agents/v1/agents.proto
@@ -627,6 +627,9 @@ message Environment {
   // Vendor model names a native-mode workload may request, enforced by the LLM
   // Proxy. Empty means no restriction. Ignored in platform mode.
   repeated string llm_allowed_models = 15;
+  // Whether shells in workloads here outlive the connections that reach them.
+  // Defaults to true.
+  bool persistent_shells = 16;
 }
 
 message CreateEnvironmentRequest {
@@ -644,6 +647,8 @@ message CreateEnvironmentRequest {
   // Unspecified defaults to PLATFORM.
   LLMMode llm_mode = 12;
   repeated string llm_allowed_models = 13;
+  // Unset defaults to true.
+  optional bool persistent_shells = 14;
 }
 
 message CreateEnvironmentResponse {
@@ -676,6 +681,7 @@ message UpdateEnvironmentRequest {
   optional LLMMode llm_mode = 12;
   // Replaces the existing list; an empty list clears the allowlist.
   repeated string llm_allowed_models = 13;
+  optional bool persistent_shells = 14;
 }
 
 message UpdateEnvironmentResponse {
diff --git a/proto/agynio/api/gateway/v1/terminal.proto b/proto/agynio/api/gateway/v1/terminal.proto
index 9da0088..9a1f2f4 100644
--- a/proto/agynio/api/gateway/v1/terminal.proto
+++ b/proto/agynio/api/gateway/v1/terminal.proto
@@ -25,8 +25,8 @@ message CreateTerminalSessionRequest {
   // absolute.
   string sync_root = 5;
 
-  // Names the shell. Required when kind is SHELL_ATTACH, ignored otherwise.
-  // Opaque, ^[A-Za-z0-9_-]{1,64}$.
+  // Names the shell to attach to. Optional; meaningful only when kind is
+  // SHELL and the workload keeps shells. Opaque, ^[A-Za-z0-9_-]{1,64}$.
   string shell_id = 6;
 
   // Working directory for the shell. Optional; applied when the shell is
diff --git a/proto/agynio/api/runners/v1/runners.proto b/proto/agynio/api/runners/v1/runners.proto
index 4a437ed..d1f635d 100644
--- a/proto/agynio/api/runners/v1/runners.proto
+++ b/proto/agynio/api/runners/v1/runners.proto
@@ -395,6 +395,9 @@ message Workload {
   int64 allocated_ram_bytes = 14;
   // Flavor the workload started on. Empty when it started without an environment.
   string flavor = 26;
+  // 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;
   // 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;
@@ -436,6 +439,8 @@ message CreateWorkloadRequest {
   // Present when owner_kind is RUNTIME_OWNER_KIND_AGENT_INSTANCE; absent otherwise.
   optional string agent_instance_id = 14;
   string flavor = 15;
+  // Whether shells in this workload outlive the connections that reach them.
+  bool persistent_shells = 16;
 }
 
 message CreateWorkloadResponse {
diff --git a/proto/agynio/api/terminal_proxy/v1/terminal_proxy.proto b/proto/agynio/api/terminal_proxy/v1/terminal_proxy.proto
index bfab652..b6944a9 100644
--- a/proto/agynio/api/terminal_proxy/v1/terminal_proxy.proto
+++ b/proto/agynio/api/terminal_proxy/v1/terminal_proxy.proto
@@ -18,7 +18,8 @@ enum SessionKind {
   // ends up in a ticket.
   SESSION_KIND_UNSPECIFIED = 0;
 
-  // A login shell on a PTY. The PTY closes with the connection.
+  // A shell on a PTY. Whether it outlives the connection is decided by the
+  // workload, not by this request.
   SESSION_KIND_SHELL = 1;
 
   // A caller-supplied command on a PTY. Carries no more privilege than SHELL —
@@ -29,10 +30,10 @@ enum SessionKind {
   // separate from stderr so diagnostics cannot corrupt protocol frames.
   SESSION_KIND_SYNC = 3;
 
-  // A PTY on a named shell that outlives the session. Attaches to shell_id,
-  // creating it when it does not exist. A second session on the same shell
-  // displaces the first.
-  SESSION_KIND_SHELL_ATTACH = 4;
+  // Deprecated: use SHELL. Whether a shell outlives its connection is a
+  // property of the workload rather than a choice the caller makes, so SHELL
+  // covers both. Accepted as an alias for SHELL.
+  SESSION_KIND_SHELL_ATTACH = 4 [deprecated = true];
 }
 
 message IssueTicketRequest {
@@ -54,13 +55,13 @@ message IssueTicketRequest {
   // resolved against the real filesystem inside the container.
   string sync_root = 6;
 
-  // Names the shell. Required when kind is SHELL_ATTACH, ignored otherwise.
-  // Client-generated and opaque, matching ^[A-Za-z0-9_-]{1,64}$.
+  // Names the shell to attach to. Optional; meaningful only when kind is
+  // SHELL and the workload keeps shells. Client-generated and opaque,
+  // matching ^[A-Za-z0-9_-]{1,64}$.
   string shell_id = 7;
 
-  // Working directory for the shell. Optional; meaningful only when kind is
-  // SHELL_ATTACH. Applied when the shell is created and ignored when it
-  // already exists. Must be absolute.
+  // Working directory for the shell. Optional; applied when the shell is
+  // created and ignored when it already exists. Must be absolute.
   string shell_cwd = 8;
 }