feat(memory): restore Dream model preset override (#5107)

docs/memory.md

@@ -197,13 +197,13 @@ Dream is configured under `agents.defaults.dream`:
 |-------|---------|
 | `intervalH` | How often Dream runs, in hours |
 | `cron` | Cron expression override (takes precedence over `intervalH`) |
-| `modelOverride` | Optional Dream-specific model override *(pending implementation)* |
+| `modelOverride` | Optional model preset name used for Dream |
 
 In practical terms:
 
 - `intervalH` is the normal way to configure Dream frequency. Internally it runs as an `every` schedule.
 - `cron` overrides `intervalH` when set, allowing precise cron expressions (e.g. `0 */4 * * *`).
-- `modelOverride` is reserved for a future release. Currently Dream uses the same model as the main agent.
+- `modelOverride` selects a named entry from `model_presets` for Dream. It accepts preset names only; raw model identifiers are not supported. If omitted, Dream uses the main agent's selected runtime.
 
 ## In Practice
 

nanobot/agent/loop.py

@@ -220,6 +220,12 @@ class AgentLoop:
             self._publish_runtime_selection(runtime)
         return runtime
 
+    def dream_runtime(self) -> LLMRuntime | None:
+        """Resolve the optional preset used for Dream without changing defaults."""
+        if not self.dream_model_preset:
+            return None
+        return self.runtime_resolver.resolve_preset(self.dream_model_preset)
+
     _RUNTIME_CHECKPOINT_KEY = "runtime_checkpoint"
     _PENDING_USER_TURN_KEY = "pending_user_turn"
 
@@ -257,6 +263,7 @@ class AgentLoop:
         model_presets: dict[str, ModelPresetConfig] | None = None,
         preset_catalog_loader: preset_helpers.PresetCatalogLoader | None = None,
         model_preset: str | None = None,
+        dream_model_preset: str | None = None,
         preset_snapshot_loader: preset_helpers.PresetSnapshotLoader | None = None,
         runtime_events: RuntimeEventBus | None = None,
         turn_delivery_factory: TurnDeliveryFactory | None = None,
@@ -311,6 +318,7 @@ class AgentLoop:
             provider_snapshot_loader=provider_snapshot_loader,
             preset_snapshot_loader=preset_snapshot_loader,
         )
+        self.dream_model_preset = dream_model_preset
         self.context_block_limit = context_block_limit
         self.max_tool_result_chars = (
             max_tool_result_chars
@@ -474,6 +482,7 @@ class AgentLoop:
             tools_config=config.tools,
             model_presets=preset_helpers.configured_model_presets(config),
             model_preset=defaults.model_preset,
+            dream_model_preset=defaults.dream.model_override,
             restart_mode=config.gateway.restart_mode,
             provider_snapshot_loader=provider_snapshot_loader,
             preset_snapshot_loader=preset_snapshot_loader,
@@ -1573,6 +1582,12 @@ class AgentLoop:
         if runtime is None:
             runtime = self.runtime_for_session(ctx.session)
             ctx.runtime = runtime
+        if ctx.session_key.startswith("dream:"):
+            logger.info(
+                "Dream run using model={} (preset={})",
+                runtime.model,
+                runtime.model_preset or "default",
+            )
         if ctx.on_runtime_admitted is not None:
             await ctx.on_runtime_admitted(runtime)
         replay_max_messages = replay_max_messages_for_context(

nanobot/cli/commands.py

@@ -1820,12 +1820,17 @@ def _run_gateway(
                     return None
                 prompt, last_cursor = result
                 key = dream_session_key()
+                resolve_dream_runtime = getattr(agent, "dream_runtime", None)
+                dream_runtime = (
+                    resolve_dream_runtime() if callable(resolve_dream_runtime) else None
+                )
                 resp = await agent.process_direct(
                     prompt,
                     session_key=key,
                     ephemeral=True,
                     tools=store.build_dream_tools(),
                     on_progress=progress,
+                    runtime=dream_runtime,
                 )
                 # The real file delta grounds the audit record; clean completion
                 # decides whether this history batch has finished processing.

nanobot/command/builtin.py

@@ -427,12 +427,15 @@ async def cmd_dream(ctx: CommandContext) -> OutboundMessage:
                 return
             prompt, last_cursor = result
             key = dream_session_key()
+            resolve_dream_runtime = getattr(loop, "dream_runtime", None)
+            dream_runtime = resolve_dream_runtime() if callable(resolve_dream_runtime) else None
             resp = await loop.process_direct(
                 prompt,
                 session_key=key,
                 ephemeral=True,
                 tools=store.build_dream_tools(),
                 on_progress=progress,
+                runtime=dream_runtime,
             )
             elapsed = time.monotonic() - t0
             # The real file delta grounds the audit record; clean completion

nanobot/config/schema.py

@@ -63,7 +63,7 @@ class DreamConfig(Base):
     model_override: str | None = Field(
         default=None,
         validation_alias=AliasChoices("modelOverride", "model", "model_override"),
-    )  # Override model for Dream sessions (pending implementation)
+    )  # Model preset name for Dream sessions
 
     def build_schedule(self, timezone: str) -> CronSchedule:
         """Build the runtime schedule, preferring the legacy cron override if present."""
@@ -436,6 +436,9 @@ class Config(BaseSettings):
         name = self.agents.defaults.model_preset
         if name and name != "default" and name not in self.model_presets:
             raise ValueError(f"model_preset {name!r} not found in model_presets")
+        dream_name = self.agents.defaults.dream.model_override
+        if dream_name and dream_name != "default" and dream_name not in self.model_presets:
+            raise ValueError(f"Dream model preset {dream_name!r} not found in model_presets")
         for fallback in self.agents.defaults.fallback_models:
             if isinstance(fallback, str) and fallback not in self.model_presets:
                 raise ValueError(f"fallback_models entry {fallback!r} not found in model_presets")

tests/agent/test_dream.py

@@ -3,6 +3,7 @@
 import pytest
 
 from nanobot.agent.memory import MemoryStore
+from nanobot.config.schema import ModelPresetConfig
 from nanobot.providers.base import LLMResponse
 from nanobot.security.workspace_access import (
     bind_workspace_scope,
@@ -385,6 +386,21 @@ class TestEphemeralDirect:
 
         return loop, store
 
+    def test_dream_runtime_uses_preset_without_changing_default(self, _make_loop):
+        loop, _ = _make_loop
+        loop.runtime_resolver._model_presets = {
+            "dream": ModelPresetConfig(model="dream-model"),
+        }
+        loop.dream_model_preset = "dream"
+
+        runtime = loop.dream_runtime()
+
+        assert runtime is not None
+        assert runtime.model == "dream-model"
+        assert runtime.model_preset == "dream"
+        assert loop.model == "test-model"
+        assert loop.model_preset is None
+
     async def test_ephemeral_skips_raw_archive(self, tmp_path, _make_loop):
         """When ephemeral=True, raw_archive must not be called."""
         from unittest.mock import patch

tests/command/test_builtin_dream.py

@@ -171,11 +171,13 @@ async def test_dream_internal_run_silences_progress(tmp_path) -> None:
 
     sessions_dir = tmp_path / "sessions"
     sessions_dir.mkdir()
+    dream_runtime = object()
     loop = SimpleNamespace(
         bus=bus,
         context=SimpleNamespace(memory=store, timezone="UTC"),
         sessions=SimpleNamespace(sessions_dir=sessions_dir),
         process_direct=process_direct,
+        dream_runtime=lambda: dream_runtime,
     )
     ctx = CommandContext(msg=msg, session=None, key=msg.session_key, raw="/dream", args="", loop=loop)
 
@@ -184,6 +186,7 @@ async def test_dream_internal_run_silences_progress(tmp_path) -> None:
 
     assert len(calls) == 1
     assert callable(calls[0][1]["on_progress"])
+    assert calls[0][1]["runtime"] is dream_runtime
 
 
 def _build_runnable_dream(

tests/config/test_model_presets.py

@@ -267,6 +267,24 @@ def test_validator_rejects_unknown_preset() -> None:
         })
 
 
+def test_validator_accepts_dream_model_preset() -> None:
+    config = Config.model_validate({
+        "modelPresets": {
+            "dream": {"model": "anthropic/claude-haiku-4-5", "provider": "anthropic"},
+        },
+        "agents": {"defaults": {"dream": {"modelOverride": "dream"}}},
+    })
+
+    assert config.agents.defaults.dream.model_override == "dream"
+
+
+def test_validator_rejects_unknown_dream_model_preset() -> None:
+    with pytest.raises(ValueError, match="Dream model preset 'unknown' not found"):
+        Config.model_validate({
+            "agents": {"defaults": {"dream": {"modelOverride": "unknown"}}},
+        })
+
+
 def test_model_preset_accepts_explicit_default_name() -> None:
     config = Config.model_validate({
         "agents": {