agents: add size_slug convenience property to AgentSession

src/pydo/agents/session.py

@@ -339,6 +339,16 @@ def agent_kind(self) -> Optional[str]:
         get = getattr(info, "get", None)
         return get("agent_kind") if get else None
 
+    @property
+    def size_slug(self) -> Optional[str]:
+        """The sandbox size slug this session's sandbox actually booted at
+        (e.g. ``"mars-2vcpu-4gb"``), or ``None`` if unknown (a session that has
+        not reached a sandbox yet, or one created before this field existed).
+        """
+        info = self.info
+        get = getattr(info, "get", None)
+        return get("size_slug") if get else None
+
     @property
     def openai_session_id(self) -> Optional[str]:
         info = self.info

src/pydo/aio/agents/session.py

@@ -203,6 +203,16 @@ def agent_kind(self) -> Optional[str]:
         get = getattr(info, "get", None)
         return get("agent_kind") if get else None
 
+    @property
+    def size_slug(self) -> Optional[str]:
+        """The sandbox size slug this session's sandbox actually booted at
+        (e.g. ``"mars-2vcpu-4gb"``), or ``None`` if unknown (a session that has
+        not reached a sandbox yet, or one created before this field existed).
+        """
+        info = self.info
+        get = getattr(info, "get", None)
+        return get("size_slug") if get else None
+
     @property
     def openai_session_id(self) -> Optional[str]:
         info = self.info

tests/agents/test_session_highlevel.py

@@ -231,6 +231,31 @@ def test_hitl_none_leaves_prompt_unresolved():
     assert sessions.resolved == []
 
 
+# ---------------------------------------------------------------------------
+# Read-model properties
+# ---------------------------------------------------------------------------
+
+
+def test_size_slug_reads_from_session_info():
+    agent = AgentSession(
+        _FakeSessions([]),
+        "s1",
+        raw={
+            "session": {
+                "status": "ready",
+                "agent_kind": "AGENT_KIND_OPENCODE",
+                "size_slug": "mars-2vcpu-4gb",
+            }
+        },
+    )
+    assert agent.size_slug == "mars-2vcpu-4gb"
+
+
+def test_size_slug_is_none_when_absent():
+    agent = AgentSession(_FakeSessions([]), "s1", raw={"session": {"status": "ready"}})
+    assert agent.size_slug is None
+
+
 # ---------------------------------------------------------------------------
 # Lifecycle
 # ---------------------------------------------------------------------------
@@ -339,3 +364,12 @@ async def test_async_context_manager_destroys():
     async with AsyncAgentSession(sessions, "s1") as agent:
         assert agent.session_id == "s1"
     assert sessions.destroyed
+
+
+def test_async_size_slug_reads_from_session_info():
+    agent = AsyncAgentSession(
+        _FakeAsyncSessions([]),
+        "s1",
+        raw={"session": {"status": "ready", "size_slug": "mv-8vcpu-16gb"}},
+    )
+    assert agent.size_slug == "mv-8vcpu-16gb"