feat(agent): expose chat history with existing chat scope (#6443)

Co-authored-by: Raul <9117159+raultcj@users.noreply.github.com>

tests/test_codex_chat_history.py

@@ -0,0 +1,111 @@
+"""Agent chat history uses the same scope as existing chat and history routes."""
+
+import pytest
+from fastapi import APIRouter, HTTPException
+from starlette.requests import Request
+
+from routes import codex_routes
+
+
+def _endpoint(router, method: str, path: str):
+    for route in router.routes:
+        if route.path == path and method in route.methods:
+            return route.endpoint
+    raise AssertionError(f"{method} {path} route not found")
+
+
+def _request(scopes: list[str]) -> Request:
+    request = Request({
+        "type": "http",
+        "method": "GET",
+        "path": "/api/codex/chat/session-test",
+        "headers": [],
+        "state": {},
+    })
+    request.state.current_user = "api"
+    request.state.api_token = True
+    request.state.api_token_owner = "alice"
+    request.state.api_token_scopes = scopes
+    return request
+
+
+def _history_router(calls: list[tuple]):
+    router = APIRouter()
+
+    @router.get("/api/history/{session_id}")
+    async def history(
+        request: Request,
+        session_id: str,
+        limit: int | None = None,
+        offset: int | None = None,
+    ):
+        calls.append((request, session_id, limit, offset))
+        return {
+            "name": "Model debugging",
+            "model": "org/model",
+            "history": [{"role": "assistant", "content": "second"}],
+            "total": 3,
+            "offset": offset,
+            "limit": limit,
+            "endpoint_url": "http://private-endpoint",
+        }
+
+    return router
+
+
+@pytest.mark.asyncio
+async def test_history_read_uses_existing_paged_handler_without_exposing_endpoint_url():
+    calls = []
+    router = codex_routes.setup_codex_routes(history_router=_history_router(calls))
+    read_chat = _endpoint(router, "GET", "/api/codex/chat/{session_id}")
+    request = _request(["chat"])
+
+    result = await read_chat(request, "session-test", offset=1, limit=1)
+
+    assert calls == [(request, "session-test", 1, 1)]
+    assert result == {
+        "session_id": "session-test",
+        "name": "Model debugging",
+        "model": "org/model",
+        "messages": [{"role": "assistant", "content": "second"}],
+        "total": 3,
+        "offset": 1,
+        "limit": 1,
+    }
+
+
+@pytest.mark.asyncio
+async def test_token_without_chat_scope_cannot_read_history_or_reach_handler():
+    calls = []
+    router = codex_routes.setup_codex_routes(history_router=_history_router(calls))
+    read_chat = _endpoint(router, "GET", "/api/codex/chat/{session_id}")
+
+    with pytest.raises(HTTPException) as exc_info:
+        await read_chat(_request(["todos:read"]), "session-test")
+
+    assert exc_info.value.status_code == 403
+    assert calls == []
+
+
+@pytest.mark.asyncio
+async def test_history_read_uses_existing_page_limit():
+    calls = []
+    router = codex_routes.setup_codex_routes(history_router=_history_router(calls))
+    read_chat = _endpoint(router, "GET", "/api/codex/chat/{session_id}")
+
+    await read_chat(_request(["chat"]), "session-test", limit=1000)
+
+    assert calls[0][2:] == (100, 0)
+
+
+def test_capabilities_report_history_permission_from_chat_scope():
+    router = codex_routes.setup_codex_routes(history_router=_history_router([]))
+    capabilities = _endpoint(router, "GET", "/api/codex/capabilities")
+
+    without_chat = capabilities(_request(["todos:read"]))["tools"]["chat"]
+    reader = capabilities(_request(["chat"]))["tools"]["chat"]
+
+    assert without_chat["read"] is False
+    assert reader["read"] is True
+    assert reader["available"] is True
+    assert reader["actions"] == ["read"]