feat(managed_agents): add EC2SandboxViaSSM placeholder for follow-up wiring

litellm/managed_agents/sandbox/ec2_ssm.py

@@ -0,0 +1,57 @@
+"""
+EC2SandboxViaSSM — placeholder.
+
+Production sandbox: the proxy issues an SSM ``RunCommand`` to a VM
+provisioned via Epic B's vm_providers (default: EC2 in customer AWS) and
+shells out the tool call there. The VM no longer needs a custom binary —
+stock Ubuntu + the SSM agent is enough.
+
+This placeholder exists so:
+
+  * The public API (``from litellm.managed_agents.sandbox import
+    EC2SandboxViaSSM``) is stable from day one.
+  * Validation criterion #1 (clean import) passes.
+  * Future PR can swap in the real implementation without touching call
+    sites.
+
+The real implementation belongs in a follow-up that wires
+``litellm/proxy/agent_session_endpoints/vm_providers/`` (already on the
+integration branch) into ``execute_tool``. Tracked as a deferred item on
+LIT-2879.
+"""
+
+from typing import Any, Dict, Optional
+
+from litellm.managed_agents.sandbox.base import Sandbox, ToolResult
+
+
+class EC2SandboxViaSSM(Sandbox):
+    """Placeholder for SSM-backed remote execution. Not yet implemented.
+
+    Construct it freely (the public API is stable). Calling
+    ``execute_tool`` raises ``NotImplementedError`` until the SSM wiring
+    lands. The constructor takes ``team_id`` because the real implementation
+    will look up team-scoped AWS creds + the VM provisioning provider via
+    ``vm_providers.get_vm_provider("ec2")``.
+    """
+
+    def __init__(
+        self,
+        team_id: Optional[str] = None,
+        vm_id: Optional[str] = None,
+        region: Optional[str] = None,
+    ) -> None:
+        self.team_id = team_id
+        self.vm_id = vm_id
+        self.region = region
+
+    async def execute_tool(
+        self,
+        tool_name: str,
+        tool_input: Dict[str, Any],
+    ) -> ToolResult:
+        raise NotImplementedError(
+            "EC2SandboxViaSSM is a placeholder. Wire it to "
+            "litellm/proxy/agent_session_endpoints/vm_providers/ec2 in a "
+            "follow-up PR."
+        )