feat(agent): make model presets session-scoped (#4866)

tests/command/test_model_command.py

@@ -16,6 +16,10 @@ from nanobot.command.builtin import (
 )
 from nanobot.command.router import CommandContext, CommandRouter
 from nanobot.config.schema import ModelPresetConfig
+from nanobot.session.model_selection import (
+    SESSION_MODEL_PRESET_METADATA_KEY,
+    model_preset_from_metadata,
+)
 
 
 def _provider(default_model: str, max_tokens: int = 123) -> MagicMock:
@@ -29,7 +33,7 @@ def _provider(default_model: str, max_tokens: int = 123) -> MagicMock:
     return provider
 
 
-def _make_loop(tmp_path) -> AgentLoop:
+def _make_loop(tmp_path, *, preset_snapshot_loader=None) -> AgentLoop:
     return AgentLoop(
         bus=MessageBus(),
         provider=_provider("base-model", max_tokens=123),
@@ -48,6 +52,7 @@ def _make_loop(tmp_path) -> AgentLoop:
                 context_window_tokens=32_768,
             ),
         },
+        preset_snapshot_loader=preset_snapshot_loader,
     )
 
 
@@ -64,6 +69,11 @@ def _ctx_session(loop: AgentLoop, raw: str, args: str = "") -> CommandContext:
     )
 
 
+def _saved_model_preset(loop: AgentLoop, session_key: str = "cli:direct") -> str | None:
+    session = loop.sessions.get_or_create(session_key)
+    return model_preset_from_metadata(session.metadata)
+
+
 @pytest.mark.asyncio
 async def test_model_command_lists_current_and_available_presets(tmp_path) -> None:
     loop = _make_loop(tmp_path)
@@ -84,23 +94,28 @@ async def test_model_command_switches_preset(tmp_path) -> None:
     out = await cmd_model(_ctx(loop, "/model fast", args="fast"))
 
     assert "Switched model preset to `fast`." in out.content
+    assert "Scope: current session" in out.content
     assert "Model: `openai/gpt-4.1`" in out.content
-    assert loop.model_preset == "fast"
-    assert loop.model == "openai/gpt-4.1"
-    assert not hasattr(loop.subagents, "model")
-    assert not hasattr(loop.consolidator, "model")
-    assert loop.llm_runtime().model == "openai/gpt-4.1"
+    assert _saved_model_preset(loop) == "fast"
+    assert loop.model_preset is None
+    assert loop.model == "base-model"
+
+    await loop.process_direct("/new", session_key="cli:direct")
+    assert _saved_model_preset(loop) == "fast"
+    status = await loop.process_direct("/status", session_key="cli:direct")
+    assert status is not None and "openai/gpt-4.1" in status.content
 
 
 @pytest.mark.asyncio
 async def test_model_command_switches_back_to_default(tmp_path) -> None:
     loop = _make_loop(tmp_path)
-    loop.set_model_preset("fast")
+    await cmd_model(_ctx(loop, "/model fast", args="fast"))
 
     out = await cmd_model(_ctx(loop, "/model default", args="default"))
 
     assert "Switched model preset to `default`." in out.content
-    assert loop.model_preset == "default"
+    assert _saved_model_preset(loop) == "default"
+    assert loop.model_preset is None
     assert loop.model == "base-model"
     assert loop.context_window_tokens == 1000
 
@@ -118,6 +133,24 @@ async def test_model_command_unknown_preset_keeps_old_state(tmp_path) -> None:
     assert loop.model == "base-model"
 
 
+@pytest.mark.asyncio
+async def test_model_command_reports_provider_configuration_errors(tmp_path) -> None:
+    def fail_preset(_name: str):
+        raise ValueError("No API key configured for provider 'openai'.")
+
+    loop = _make_loop(tmp_path, preset_snapshot_loader=fail_preset)
+
+    switched = await cmd_model(_ctx(loop, "/model fast", args="fast"))
+    session = loop.sessions.get_or_create("cli:direct")
+    session.metadata[SESSION_MODEL_PRESET_METADATA_KEY] = "fast"
+    status = await cmd_model(_ctx(loop, "/model"))
+
+    assert "Could not switch model preset" in switched.content
+    assert "No API key configured for provider 'openai'." in switched.content
+    assert "Current selection error" in status.content
+    assert "No API key configured for provider 'openai'." in status.content
+
+
 @pytest.mark.asyncio
 async def test_model_command_does_not_depend_on_my_allow_set(tmp_path) -> None:
     loop = _make_loop(tmp_path)
@@ -125,7 +158,7 @@ async def test_model_command_does_not_depend_on_my_allow_set(tmp_path) -> None:
 
     await cmd_model(_ctx(loop, "/model fast", args="fast"))
 
-    assert loop.model_preset == "fast"
+    assert _saved_model_preset(loop) == "fast"
 
 
 @pytest.mark.asyncio
@@ -142,11 +175,45 @@ async def test_model_command_registered_as_exact_and_prefix(tmp_path) -> None:
     assert out.metadata == {"render_as": "text"}
     assert out.content == "\n".join([
         "Switched model preset to `fast`.",
+        "- Scope: current session",
         "- Model: `openai/gpt-4.1`",
         "- Context window: 32768",
         "- Max output tokens: 4096",
     ])
-    assert loop.model_preset == "fast"
+    assert _saved_model_preset(loop) == "fast"
+
+
+@pytest.mark.asyncio
+async def test_model_command_does_not_change_another_session(tmp_path) -> None:
+    loop = _make_loop(tmp_path)
+
+    await cmd_model(_ctx(loop, "/model fast", args="fast"))
+    other = InboundMessage(channel="cli", sender_id="user", chat_id="other", content="/model")
+    out = await cmd_model(
+        CommandContext(msg=other, session=None, key=other.session_key, raw="/model", loop=loop)
+    )
+
+    assert "Current preset: `default`" in out.content
+    assert _saved_model_preset(loop) == "fast"
+
+
+@pytest.mark.asyncio
+async def test_model_command_reports_and_recovers_removed_session_preset(tmp_path) -> None:
+    loop = _make_loop(tmp_path)
+    session = loop.sessions.get_or_create("cli:direct")
+    session.metadata[SESSION_MODEL_PRESET_METADATA_KEY] = "removed"
+    loop.sessions.save(session)
+
+    status = await loop.process_direct("/model", session_key="cli:direct")
+    switched = await loop.process_direct("/model default", session_key="cli:direct")
+
+    assert status is not None
+    assert "model_preset 'removed' not found" in status.content
+    assert "Available presets: `default`, `fast`" in status.content
+    assert "Switch with `/model <preset>`" in status.content
+    assert switched is not None
+    assert "Switched model preset to `default`." in switched.content
+    assert _saved_model_preset(loop) == "default"
 
 
 def test_model_command_in_help_and_palette() -> None: