Studio: fix the "No model loaded" error, and optionally auto-download a model named in an API request

studio/backend/auth/authentication.py

@@ -164,6 +164,22 @@ async def get_current_subject_allow_password_change(
     )
 
 
+# The literal the examples ship with; pasting one unedited is likelier than a revoked key.
+API_KEY_PLACEHOLDER = f"{API_KEY_PREFIX}YOUR_KEY"
+
+
+def _invalid_api_key_detail(token: str) -> str:
+    """Why the key failed. Only the unedited example placeholder is called out;
+    every real key still gets one indistinguishable message, so this reveals
+    nothing about which keys exist."""
+    if token == API_KEY_PLACEHOLDER:
+        return (
+            "This is the placeholder key from the example. Create an API key in "
+            f"Unsloth Studio under Settings > API and use it in place of {API_KEY_PLACEHOLDER}."
+        )
+    return "Invalid or expired API key"
+
+
 async def _get_current_subject(
     credentials: HTTPAuthorizationCredentials, *, allow_password_change: bool
 ) -> str:
@@ -176,7 +192,7 @@ async def _get_current_subject(
         if username is None:
             raise HTTPException(
                 status_code = status.HTTP_401_UNAUTHORIZED,
-                detail = "Invalid or expired API key",
+                detail = _invalid_api_key_detail(token),
             )
         return username
 

studio/backend/core/inference/api_monitor.py

@@ -52,6 +52,13 @@ class ApiMonitorEntry:
     total_tokens: Optional[int] = None
     total_tokens_authoritative: bool = False
     error: Optional[str] = None
+    # "request" (HTTP call) or "lifecycle" (model load/unload: event/reason, not a prompt; shared).
+    kind: str = "request"
+    event: Optional[str] = None
+    reason: Optional[str] = None
+    shared: bool = False
+    # 0-100 for a running download row; None when not applicable.
+    progress: Optional[float] = None
 
     def snapshot(self, *, include_details: bool = True) -> dict[str, Any]:
         duration_ms = None
@@ -85,6 +92,10 @@ def snapshot(self, *, include_details: bool = True) -> dict[str, Any]:
             "completion_tokens": self.completion_tokens,
             "total_tokens": self.total_tokens,
             "error": self.error,
+            "kind": self.kind,
+            "event": self.event,
+            "reason": self.reason,
+            "progress": self.progress,
         }
         if include_details:
             payload["prompt"] = self.prompt
@@ -127,6 +138,75 @@ def start(
             self._trim_terminal_locked()
         return entry.id
 
+    def record_lifecycle(
+        self,
+        *,
+        event: str,
+        model: str,
+        reason: Optional[str] = None,
+        running: bool = False,
+    ) -> str:
+        """Record a model load/unload alongside the request traffic that caused it.
+
+        ``running=True`` opens the row (a load in progress) and the caller closes
+        it with the usual :meth:`finish` / :meth:`fail`; an unload is terminal on
+        arrival. Rows are shared, so every subject sees them, and share the same
+        retention budget as requests.
+        """
+        now = time.time()
+        entry = ApiMonitorEntry(
+            id = f"apievt_{uuid.uuid4().hex[:12]}",
+            endpoint = f"model.{event}",
+            method = "",
+            model = model or "default",
+            prompt = "",
+            status = "running" if running else "completed",
+            started_at = now,
+            updated_at = now,
+            started_monotonic = time.monotonic(),
+            finished_at = None if running else now,
+            finished_monotonic = None if running else time.monotonic(),
+            kind = "lifecycle",
+            event = event,
+            reason = reason,
+            shared = True,
+        )
+        with self._lock:
+            self._entries.appendleft(entry)
+            self._trim_terminal_locked()
+        return entry.id
+
+    def relabel(self, entry_id: Optional[str], model: str) -> None:
+        """Rename an open lifecycle row once the load resolves its real id (the
+        caller only has the load path up front, which may be an HF snapshot dir)."""
+        if not entry_id or not model:
+            return
+        with self._lock:
+            entry = self._find_locked(entry_id)
+            if entry is not None:
+                entry.model = model
+                entry.updated_at = time.time()
+
+    def set_progress(self, entry_id: Optional[str], progress: Optional[float]) -> None:
+        """Update an open download row's percentage (clamped to 0-100)."""
+        if not entry_id or progress is None:
+            return
+        with self._lock:
+            entry = self._find_locked(entry_id)
+            if entry is not None and entry.status == "running":
+                entry.progress = min(100.0, max(0.0, float(progress)))
+                entry.updated_at = time.time()
+
+    def discard(self, entry_id: Optional[str]) -> None:
+        """Drop a row that turned out not to be an event (a load that was already
+        satisfied, so nothing was actually loaded)."""
+        if not entry_id:
+            return
+        with self._lock:
+            entry = self._find_locked(entry_id)
+            if entry is not None:
+                self._entries.remove(entry)
+
     def append_reply(self, entry_id: Optional[str], text: str) -> None:
         if not entry_id or not text:
             return
@@ -212,6 +292,19 @@ def finish(
             self._entries.appendleft(entry)
             self._trim_terminal_locked()
 
+    def fail_open(self, entry_id: Optional[str], error: str) -> None:
+        """Fail only a still-open row. Unlike :meth:`fail` this never touches an
+        entry that already finished, so a catch-all in a ``finally`` cannot stamp
+        an error onto a request that in fact succeeded."""
+        if not entry_id:
+            return
+        with self._lock:
+            entry = self._find_locked(entry_id)
+            if entry is None or entry.finished_at is not None:
+                return
+            # Same lock as the check, so a finish() cannot land in between.
+            self._fail_locked(entry, error)
+
     def fail(self, entry_id: Optional[str], error: str) -> None:
         if not entry_id:
             return
@@ -224,15 +317,18 @@ def fail(self, entry_id: Optional[str], error: str) -> None:
                 if error:
                     entry.error = _trim(error, 1000)
                 return
-            now = time.time()
-            entry.status = "error"
-            entry.error = _trim(error, 1000)
-            entry.updated_at = now
-            entry.finished_at = now
-            entry.finished_monotonic = time.monotonic()
-            self._entries.remove(entry)
-            self._entries.appendleft(entry)
-            self._trim_terminal_locked()
+            self._fail_locked(entry, error)
+
+    def _fail_locked(self, entry: ApiMonitorEntry, error: str) -> None:
+        now = time.time()
+        entry.status = "error"
+        entry.error = _trim(error, 1000)
+        entry.updated_at = now
+        entry.finished_at = now
+        entry.finished_monotonic = time.monotonic()
+        self._entries.remove(entry)
+        self._entries.appendleft(entry)
+        self._trim_terminal_locked()
 
     def snapshot(
         self,
@@ -244,7 +340,7 @@ def snapshot(
             return [
                 entry.snapshot(include_details = include_details)
                 for entry in self._entries
-                if subject is None or entry.subject == subject
+                if self._visible(entry, subject)
             ]
 
     def get(
@@ -257,22 +353,29 @@ def get(
             entry = self._find_locked(entry_id)
             if entry is None:
                 return None
-            if subject is not None and entry.subject != subject:
+            if not self._visible(entry, subject):
                 return None
             return entry.snapshot(include_details = True)
 
     def active_count(self, *, subject: Optional[str] = None) -> int:
+        # Lifecycle rows show as "running" while loading but are not in-flight API requests.
         with self._lock:
             return sum(
                 1
                 for entry in self._entries
-                if entry.status == "running" and (subject is None or entry.subject == subject)
+                if entry.status == "running"
+                and entry.kind != "lifecycle"
+                and (subject is None or entry.subject == subject)
             )
 
     def clear(self) -> None:
         with self._lock:
             self._entries.clear()
 
+    @staticmethod
+    def _visible(entry: ApiMonitorEntry, subject: Optional[str]) -> bool:
+        return subject is None or entry.subject == subject or entry.shared
+
     def _find_locked(self, entry_id: str) -> Optional[ApiMonitorEntry]:
         for entry in self._entries:
             if entry.id == entry_id:

studio/backend/core/inference/llama_keepwarm.py

@@ -345,6 +345,22 @@ def _loaded_identity(backend):
     return (backend.model_identifier, getattr(backend, "hf_variant", None), advertised)
 
 
+def _note_idle_unload_event(freed) -> None:
+    """Record an idle auto-unload in the API monitor, using the advertised repo id
+    from the stash so the row never shows the on-disk load path. Best-effort."""
+    try:
+        from core.inference.api_monitor import api_monitor
+        from core.inference.model_ids import public_model_id
+
+        identifier, variant, advertised = (list(freed) + [None, None, None])[:3]
+        label = public_model_id(advertised or identifier) or "model"
+        if variant and ":" not in label:
+            label = f"{label}:{variant}"
+        api_monitor.record_lifecycle(event = "unload", model = label, reason = "idle")
+    except Exception as exc:
+        logger.debug("idle unload monitor event failed: %s", exc)
+
+
 async def idle_unload_loop(poll_seconds: float = 15.0) -> None:
     """Unload the loaded GGUF once idle past the configured TTL. Inert when off."""
     from utils.openai_auto_switch_settings import (
@@ -407,6 +423,8 @@ async def idle_unload_loop(poll_seconds: float = 15.0) -> None:
                     elif manifest:
                         _delete_resume_files(manifest)
                     logger.info("Idle auto-unload: freed GGUF after %ss idle", ttl)
+                    # An idle unload stashes for reload and skips note_model_unloaded.
+                    _note_idle_unload_event(freed)
                     seen_model = None
         except Exception as exc:
             logger.debug("idle_unload_loop iteration failed: %s", exc)