diff --git a/DO_OPENAPI_COMMIT_SHA.txt b/DO_OPENAPI_COMMIT_SHA.txt
index 7ffb1d26..19fa9c1d 100644
--- a/DO_OPENAPI_COMMIT_SHA.txt
+++ b/DO_OPENAPI_COMMIT_SHA.txt
@@ -1 +1 @@
-7e5b46e
+1835a59
diff --git a/tests/mocked/test_agents_sessions.py b/tests/mocked/test_agents_sessions.py
new file mode 100644
index 00000000..b999d07e
--- /dev/null
+++ b/tests/mocked/test_agents_sessions.py
@@ -0,0 +1,90 @@
+"""Placeholder mocked tests for Hosted Agents sessions (MARSOHS-551).
+
+Regeneration (blocked until openapi#1207 merges or a local SPEC_FILE is used):
+
+1. Land https://github.com/digitalocean/openapi/pull/1207 (commit 1835a59) —
+   `/v2/agents/sessions` + `session_origin` models.
+2. Either:
+   - `workflow_dispatch` `.github/workflows/python-client-gen.yml` with
+     `openapi_short_sha=1835a59` once the Spaces-published bundle exists, or
+   - Locally: bundle the openapi PR tip, then
+     `SPEC_FILE=/path/to/DigitalOcean-public.v2.yaml make generate`
+3. Re-enable / extend these tests against the generated `Client.agents` surface.
+   Expected Origin wire: `session.origin.product` in
+   {direct, simulation, evaluation}; ListSessions omits sim/eval server-side.
+
+Until Autorest regenerates operations from that SHA, these tests skip so CI stays green.
+"""
+
+from __future__ import annotations
+
+import pytest
+import responses
+
+from pydo import Client
+
+EXPECTED_LIST = {
+    "sessions": [
+        {
+            "session_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
+            "name": "demo-agent",
+            "status": "SESSION_STATUS_READY",
+            "origin": {
+                "product": "direct",
+                "verified": True,
+            },
+        }
+    ],
+    "next_page_token": "",
+}
+
+EXPECTED_GET = {
+    "session": {
+        "session_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
+        "name": "demo-agent",
+        "status": "SESSION_STATUS_READY",
+        "origin": {
+            "product": "direct",
+            "verified": True,
+        },
+    }
+}
+
+
+def _agents_operations_ready() -> bool:
+    client = Client("", endpoint="https://testing.local")
+    agents = getattr(client, "agents", None)
+    return agents is not None and hasattr(agents, "list_sessions")
+
+
+pytestmark = pytest.mark.skipif(
+    not _agents_operations_ready(),
+    reason="awaiting Autorest regen from openapi@1835a59 (digitalocean/openapi#1207)",
+)
+
+
+@responses.activate
+def test_agents_list_sessions(mock_client: Client, mock_client_url):
+    """Mocks GET /v2/agents/sessions including session.origin."""
+    responses.add(
+        responses.GET,
+        f"{mock_client_url}/v2/agents/sessions",
+        json=EXPECTED_LIST,
+    )
+    got = mock_client.agents.list_sessions()
+    assert got == EXPECTED_LIST
+    assert got["sessions"][0]["origin"]["product"] == "direct"
+
+
+@responses.activate
+def test_agents_get_session(mock_client: Client, mock_client_url):
+    """Mocks GET /v2/agents/sessions/{session_id} including session.origin."""
+    session_id = "a1b2c3d4-e5f6-7890-abcd-ef1234567890"
+    responses.add(
+        responses.GET,
+        f"{mock_client_url}/v2/agents/sessions/{session_id}",
+        json=EXPECTED_GET,
+    )
+    got = mock_client.agents.get_session(session_id)
+    assert got == EXPECTED_GET
+    assert got["session"]["origin"]["product"] == "direct"