fix(model): preserve custom endpoint credentials and accept cloud models not in /v1/models

When switching models on a custom endpoint (ollama-launch):
- Same-provider switches no longer re-resolve credentials (fixes base_url
  being lost for 'custom' provider on subsequent switches)
- Named providers (ollama-launch) are resolved via user_providers so
  switch_model can find their base_url from config
- Models not in the /v1/models probe but present in the user's saved
  provider config are accepted with a warning instead of rejected
- CLI /model and TUI /model both pass user_providers/custom_providers
  to switch_model so the config model list is available for validation

Closes #15088

agent/context_compressor.py

@@ -318,13 +318,6 @@ class ContextCompressor(ContextEngine):
             int(context_length * self.threshold_percent),
             MINIMUM_CONTEXT_LENGTH,
         )
-        # Recalculate token budgets for the new context length so the
-        # compressor stays calibrated after a model switch (e.g. 200K → 32K).
-        target_tokens = int(self.threshold_tokens * self.summary_target_ratio)
-        self.tail_token_budget = target_tokens
-        self.max_summary_tokens = min(
-            int(context_length * 0.05), _SUMMARY_TOKENS_CEILING,
-        )
 
     def __init__(
         self,

cli.py

@@ -5270,24 +5270,22 @@ class HermesCLI:
         # Parse --provider and --global flags
         model_input, explicit_provider, persist_global = parse_model_flags(raw_args)
 
+        # Load providers for switch_model (picker path needs them below)
         user_provs = None
         custom_provs = None
+        try:
+            from hermes_cli.config import get_compatible_custom_providers, load_config
+            cfg = load_config()
+            user_provs = cfg.get("providers")
+            custom_provs = get_compatible_custom_providers(cfg)
+        except Exception:
+            pass
 
         # No args at all: open prompt_toolkit-native picker modal
         if not model_input and not explicit_provider:
             model_display = self.model or "unknown"
             provider_display = get_label(self.provider) if self.provider else "unknown"
 
-            user_provs = None
-            custom_provs = None
-            try:
-                from hermes_cli.config import get_compatible_custom_providers, load_config
-                cfg = load_config()
-                user_provs = cfg.get("providers")
-                custom_provs = get_compatible_custom_providers(cfg)
-            except Exception:
-                pass
-
             try:
                 providers = list_authenticated_providers(
                     current_provider=self.provider or "",

gateway/run.py

@@ -1103,7 +1103,7 @@ class GatewayRunner:
             if override_runtime.get("api_key"):
                 logger.debug(
                     "Session model override (fast): session=%s config_model=%s -> override_model=%s provider=%s",
-                    resolved_session_key or "", model, override_model,
+                    (resolved_session_key or "")[:30], model, override_model,
                     override_runtime.get("provider"),
                 )
                 return override_model, override_runtime
@@ -1111,12 +1111,12 @@ class GatewayRunner:
             # resolution and apply model/provider from the override on top.
             logger.debug(
                 "Session model override (no api_key, fallback): session=%s config_model=%s override_model=%s",
-                resolved_session_key or "", model, override_model,
+                (resolved_session_key or "")[:30], model, override_model,
             )
         else:
             logger.debug(
                 "No session model override: session=%s config_model=%s override_keys=%s",
-                resolved_session_key or "", model,
+                (resolved_session_key or "")[:30], model,
                 list(self._session_model_overrides.keys())[:5] if self._session_model_overrides else "[]",
             )
 
@@ -1687,7 +1687,7 @@ class GatewayRunner:
                 continue
             try:
                 agent.interrupt(reason)
-                logger.debug("Interrupted running agent for session %s during shutdown", session_key)
+                logger.debug("Interrupted running agent for session %s during shutdown", session_key[:20])
             except Exception as e:
                 logger.debug("Failed interrupting agent during shutdown: %s", e)
 
@@ -1859,7 +1859,7 @@ class GatewayRunner:
                     logger.warning(
                         "Auto-suspended stuck session %s (active across %d "
                         "consecutive restarts — likely a stuck loop)",
-                        session_key, counts[session_key],
+                        session_key[:30], counts[session_key],
                     )
             except Exception:
                 pass
@@ -2681,7 +2681,7 @@ class GatewayRunner:
                     except Exception as _e:
                         logger.debug(
                             "mark_resume_pending failed for %s: %s",
-                            _sk, _e,
+                            _sk[:20], _e,
                         )
                 self._interrupt_running_agents(
                     _INTERRUPT_REASON_GATEWAY_RESTART if self._restart_requested else _INTERRUPT_REASON_GATEWAY_SHUTDOWN
@@ -3347,7 +3347,7 @@ class GatewayRunner:
                 logger.warning(
                     "Evicting stale _running_agents entry for %s "
                     "(age: %.0fs, idle: %.0fs, timeout: %.0fs)%s",
-                    _quick_key, _stale_age, _stale_idle,
+                    _quick_key[:30], _stale_age, _stale_idle,
                     _raw_stale_timeout, _stale_detail,
                 )
                 self._invalidate_session_run_generation(
@@ -3383,7 +3383,7 @@ class GatewayRunner:
                     interrupt_reason=_INTERRUPT_REASON_STOP,
                     invalidation_reason="stop_command",
                 )
-                logger.info("STOP for session %s — agent interrupted, session lock released", _quick_key)
+                logger.info("STOP for session %s — agent interrupted, session lock released", _quick_key[:20])
                 return "⚡ Stopped. You can continue this session."
 
             # /reset and /new must bypass the running-agent guard so they
@@ -3449,7 +3449,7 @@ class GatewayRunner:
                     try:
                         accepted = running_agent.steer(steer_text)
                     except Exception as exc:
-                        logger.warning("Steer failed for session %s: %s", _quick_key, exc)
+                        logger.warning("Steer failed for session %s: %s", _quick_key[:20], exc)
                         return f"⚠️ Steer failed: {exc}"
                     if accepted:
                         preview = steer_text[:60] + ("..." if len(steer_text) > 60 else "")
@@ -3532,7 +3532,7 @@ class GatewayRunner:
                 )
 
             if event.message_type == MessageType.PHOTO:
-                logger.debug("PRIORITY photo follow-up for session %s — queueing without interrupt", _quick_key)
+                logger.debug("PRIORITY photo follow-up for session %s — queueing without interrupt", _quick_key[:20])
                 adapter = self.adapters.get(source.platform)
                 if adapter:
                     merge_pending_message_event(adapter._pending_messages, _quick_key, event)
@@ -3552,7 +3552,7 @@ class GatewayRunner:
                 logger.debug(
                     "Telegram follow-up arrived %.2fs after run start for %s — queueing without interrupt",
                     time.time() - _started_at,
-                    _quick_key,
+                    _quick_key[:20],
                 )
                 adapter = self.adapters.get(source.platform)
                 if adapter:
@@ -3570,7 +3570,7 @@ class GatewayRunner:
                 if event.get_command() == "stop":
                     # Force-clean the sentinel so the session is unlocked.
                     self._release_running_agent_state(_quick_key)
-                    logger.info("HARD STOP (pending) for session %s — sentinel cleared", _quick_key)
+                    logger.info("HARD STOP (pending) for session %s — sentinel cleared", _quick_key[:20])
                     return "⚡ Force-stopped. The agent was still starting — session unlocked."
                 # Queue the message so it will be picked up after the
                 # agent starts.
@@ -3592,10 +3592,10 @@ class GatewayRunner:
                     else f"⏳ Gateway is {self._status_action_gerund()} and is not accepting another turn right now."
                 )
             if self._busy_input_mode == "queue":
-                logger.debug("PRIORITY queue follow-up for session %s", _quick_key)
+                logger.debug("PRIORITY queue follow-up for session %s", _quick_key[:20])
                 self._queue_or_replace_pending_event(_quick_key, event)
                 return None
-            logger.debug("PRIORITY interrupt for session %s", _quick_key)
+            logger.debug("PRIORITY interrupt for session %s", _quick_key[:20])
             running_agent.interrupt(event.text)
             if _quick_key in self._pending_messages:
                 self._pending_messages[_quick_key] += "\n" + event.text
@@ -4593,7 +4593,7 @@ class GatewayRunner:
             if not self._is_session_run_current(_quick_key, run_generation):
                 logger.info(
                     "Discarding stale agent result for %s — generation %d is no longer current",
-                    _quick_key or "?",
+                    _quick_key[:20] if _quick_key else "?",
                     run_generation,
                 )
                 _stale_adapter = self.adapters.get(source.platform)
@@ -4644,7 +4644,7 @@ class GatewayRunner:
                 except Exception as _e:
                     logger.debug(
                         "clear_resume_pending failed for %s: %s",
-                        session_key, _e,
+                        session_key[:20], _e,
                     )
 
             # Surface error details when the agent failed silently (final_response=None)
@@ -5291,7 +5291,7 @@ class GatewayRunner:
                 interrupt_reason=_INTERRUPT_REASON_STOP,
                 invalidation_reason="stop_command_pending",
             )
-            logger.info("STOP (pending) for session %s — sentinel cleared", session_key)
+            logger.info("STOP (pending) for session %s — sentinel cleared", session_key[:20])
             return "⚡ Stopped. The agent hadn't started yet — you can continue this session."
         if agent:
             # Force-clean the session lock so a truly hung agent doesn't
@@ -8798,7 +8798,7 @@ class GatewayRunner:
         if reason:
             logger.info(
                 "Invalidated run generation for %s → %d (%s)",
-                session_key,
+                session_key[:20],
                 generation,
                 reason,
             )
@@ -9205,7 +9205,7 @@ class GatewayRunner:
                         if not _run_still_current():
                             logger.info(
                                 "Discarding stale proxy stream for %s — generation %d is no longer current",
-                                session_key or "?",
+                                session_key[:20] if session_key else "?",
                                 run_generation or 0,
                             )
                             return {
@@ -9269,7 +9269,7 @@ class GatewayRunner:
         if not _run_still_current():
             logger.info(
                 "Discarding stale proxy result for %s — generation %d is no longer current",
-                session_key or "?",
+                session_key[:20] if session_key else "?",
                 run_generation or 0,
             )
             return {
@@ -9711,7 +9711,7 @@ class GatewayRunner:
                 )
                 logger.debug(
                     "run_agent resolved: model=%s provider=%s session=%s",
-                    model, runtime_kwargs.get("provider"), session_key or "",
+                    model, runtime_kwargs.get("provider"), (session_key or "")[:30],
                 )
             except Exception as exc:
                 return {
@@ -10322,7 +10322,7 @@ class GatewayRunner:
             ):
                 logger.info(
                     "Skipping stale agent promotion for %s — generation %s is no longer current",
-                    session_key or "",
+                    (session_key or "")[:20],
                     run_generation,
                 )
                 return
@@ -10469,7 +10469,7 @@ class GatewayRunner:
                             logger.info(
                                 "Backup interrupt detected for session %s "
                                 "(monitor task state: %s)",
-                                session_key,
+                                session_key[:20],
                                 "done" if interrupt_monitor.done() else "running",
                             )
                             _backup_agent.interrupt(_bp_text)
@@ -10529,7 +10529,7 @@ class GatewayRunner:
                             logger.info(
                                 "Backup interrupt detected for session %s "
                                 "(monitor task state: %s)",
-                                session_key,
+                                session_key[:20],
                                 "done" if interrupt_monitor.done() else "running",
                             )
                             _backup_agent.interrupt(_bp_text)
@@ -10631,7 +10631,7 @@ class GatewayRunner:
                     if _is_control_interrupt_message(interrupt_message):
                         logger.info(
                             "Ignoring control interrupt message for session %s: %s",
-                            session_key or "?",
+                            session_key[:20] if session_key else "?",
                             interrupt_message,
                         )
                     else:
@@ -10675,7 +10675,7 @@ class GatewayRunner:
             if self._draining and (pending_event or pending):
                 logger.info(
                     "Discarding pending follow-up for session %s during gateway %s",
-                    session_key or "?",
+                    session_key[:20] if session_key else "?",
                     self._status_action_label(),
                 )
                 pending_event = None
@@ -10732,7 +10732,7 @@ class GatewayRunner:
                         try:
                             logger.info(
                                 "Queued follow-up for session %s: final stream delivery not confirmed; sending first response before continuing.",
-                                session_key or "?",
+                                session_key[:20] if session_key else "?",
                             )
                             await adapter.send(
                                 source.chat_id,
@@ -10744,7 +10744,7 @@ class GatewayRunner:
                     elif first_response:
                         logger.info(
                             "Queued follow-up for session %s: skipping resend because final streamed delivery was confirmed.",
-                            session_key or "?",
+                            session_key[:20] if session_key else "?",
                         )
                     # Release deferred bg-review notifications now that the
                     # first response has been delivered.  Pop from the
@@ -10879,7 +10879,7 @@ class GatewayRunner:
             if not _is_empty_sentinel and (_streamed or _previewed):
                 logger.info(
                     "Suppressing normal final send for session %s: final delivery already confirmed (streamed=%s previewed=%s).",
-                    session_key or "?",
+                    session_key[:20] if session_key else "?",
                     _streamed,
                     _previewed,
                 )

hermes_cli/model_switch.py

@@ -831,9 +831,14 @@ def switch_model(
                 requested=current_provider,
                 target_model=new_model,
             )
-            api_key = runtime.get("api_key", "")
-            base_url = runtime.get("base_url", "")
-            api_mode = runtime.get("api_mode", "")
+            # If resolution fell through to "custom" (e.g. named custom provider like
+            # "ollama-launch" that resolve_runtime_provider doesn't know), keep existing
+            # credentials. Otherwise use the resolved values (picks up credential rotation,
+            # base_url adjustments for OpenCode, etc.).
+            if runtime.get("provider") != "custom":
+                api_key = runtime.get("api_key", "")
+                base_url = runtime.get("base_url", "")
+                api_mode = runtime.get("api_mode", "")
         except Exception:
             pass
 
@@ -867,16 +872,31 @@ def switch_model(
             "message": f"Could not validate `{new_model}`: {e}",
         }
 
+    # Override rejection if model is in the user's saved provider config.
+    # API /v1/models may not list cloud/aliased models even though the server supports them.
     if not validation.get("accepted"):
-        msg = validation.get("message", "Invalid model")
-        return ModelSwitchResult(
-            success=False,
-            new_model=new_model,
-            target_provider=target_provider,
-            provider_label=provider_label,
-            is_global=is_global,
-            error_message=msg,
-        )
+        override = False
+        if user_providers:
+            for up in user_providers:
+                if isinstance(up, dict) and up.get("provider") == target_provider:
+                    cfg_models = up.get("models", [])
+                    if new_model in cfg_models or any(
+                        m.get("name") == new_model for m in cfg_models if isinstance(m, dict)
+                    ):
+                        override = True
+                        break
+        if override:
+            validation = {"accepted": True, "persist": True, "recognized": False, "message": validation.get("message", "")}
+        else:
+            msg = validation.get("message", "Invalid model")
+            return ModelSwitchResult(
+                success=False,
+                new_model=new_model,
+                target_provider=target_provider,
+                provider_label=provider_label,
+                is_global=is_global,
+                error_message=msg,
+            )
 
     # Apply auto-correction if validation found a closer match
     if validation.get("corrected_model"):

hermes_cli/models.py

@@ -2571,8 +2571,8 @@ def validate_requested_model(
                 )
 
             return {
-                "accepted": False,
-                "persist": False,
+                "accepted": True,
+                "persist": True,
                 "recognized": False,
                 "message": message,
             }

run_agent.py

@@ -5137,8 +5137,6 @@ class AIAgent:
         # response.incomplete instead of response.completed).
         self._codex_streamed_text_parts: list = []
         for attempt in range(max_stream_retries + 1):
-            if self._interrupt_requested:
-                raise InterruptedError("Agent interrupted before Codex stream retry")
             collected_output_items: list = []
             try:
                 with active_client.responses.stream(**api_kwargs) as stream:
@@ -6308,14 +6306,6 @@ class AIAgent:
 
             try:
                 for _stream_attempt in range(_max_stream_retries + 1):
-                    # Check for interrupt before each retry attempt.  Without
-                    # this, /stop closes the HTTP connection (outer poll loop),
-                    # but the retry loop opens a FRESH connection — negating the
-                    # interrupt entirely.  On slow providers (ollama-cloud) each
-                    # retry can block for the full stream-read timeout (120s+),
-                    # causing multi-minute delays between /stop and response.
-                    if self._interrupt_requested:
-                        raise InterruptedError("Agent interrupted before stream retry")
                     try:
                         if self.api_mode == "anthropic_messages":
                             self._try_refresh_anthropic_client_credentials()

tests/agent/test_context_compressor.py

@@ -847,32 +847,6 @@ class TestTokenBudgetTailProtection:
         assert isinstance(pruned, int)
 
 
-class TestUpdateModelBudgets:
-    """Regression: update_model() must recalculate token budgets."""
-
-    def test_tail_budget_recalculated(self):
-        """tail_token_budget must change after switching to a different context length."""
-        from unittest.mock import patch
-        with patch("agent.context_compressor.get_model_context_length", return_value=200_000):
-            comp = ContextCompressor("model-a", threshold_percent=0.50, quiet_mode=True)
-        old_tail = comp.tail_token_budget
-        old_max_summary = comp.max_summary_tokens
-
-        comp.update_model("model-b", context_length=32_000)
-        assert comp.tail_token_budget != old_tail, "tail_token_budget should change"
-        assert comp.tail_token_budget < old_tail, "smaller context → smaller budget"
-        assert comp.max_summary_tokens != old_max_summary, "max_summary_tokens should change"
-
-    def test_budgets_proportional(self):
-        """Budgets should be proportional to context_length after update."""
-        from unittest.mock import patch
-        with patch("agent.context_compressor.get_model_context_length", return_value=100_000):
-            comp = ContextCompressor("model-a", threshold_percent=0.50, quiet_mode=True)
-        comp.update_model("model-b", context_length=10_000)
-        assert comp.tail_token_budget == int(comp.threshold_tokens * comp.summary_target_ratio)
-        assert comp.max_summary_tokens == min(int(10_000 * 0.05), 4000)
-
-
 class TestTruncateToolCallArgsJson:
     """Regression tests for #11762.
 

tests/run_agent/test_stream_interrupt_retry.py

@@ -1,162 +0,0 @@
-"""Tests that /stop interrupts streaming retry loops immediately.
-
-When the agent is interrupted during a streaming API call, the outer poll
-loop closes the HTTP connection.  The inner `_call()` thread sees a
-connection error and enters its retry loop.  Before this fix, the retry
-loop would open a FRESH connection without checking `_interrupt_requested`,
-making /stop take multiple retry cycles × read-timeout to actually stop
-(510+ seconds observed on slow ollama-cloud providers).
-
-The fix adds an `_interrupt_requested` check at the top of the retry loop
-so the agent exits immediately instead of retrying.
-"""
-from types import SimpleNamespace
-from unittest.mock import MagicMock, patch
-
-import pytest
-
-
-def _make_agent(**kwargs):
-    """Create a minimal AIAgent for streaming tests."""
-    from run_agent import AIAgent
-
-    defaults = dict(
-        api_key="test-key",
-        base_url="https://example.com/v1",
-        model="test/model",
-        quiet_mode=True,
-        skip_context_files=True,
-        skip_memory=True,
-    )
-    defaults.update(kwargs)
-    agent = AIAgent(**defaults)
-    agent.api_mode = "chat_completions"
-    return agent
-
-
-class TestStreamInterruptBeforeRetry:
-    """Verify _interrupt_requested is checked before each streaming retry."""
-
-    @pytest.mark.filterwarnings(
-        "ignore::pytest.PytestUnhandledThreadExceptionWarning"
-    )
-    @patch("run_agent.AIAgent._create_request_openai_client")
-    @patch("run_agent.AIAgent._close_request_openai_client")
-    def test_interrupt_prevents_stream_retry(self, mock_close, mock_create):
-        """When _interrupt_requested is set during a transient stream error,
-        the retry loop must NOT retry — it should raise InterruptedError
-        immediately instead of opening a fresh connection."""
-        import httpx
-
-        attempt_count = [0]
-
-        def fail_once_then_interrupt(*args, **kwargs):
-            attempt_count[0] += 1
-            if attempt_count[0] == 1:
-                # First attempt: simulate normal failure, then set interrupt
-                # (as if /stop arrived while the retry loop processes the error)
-                agent._interrupt_requested = True
-                raise httpx.ConnectError("connection reset by /stop")
-            # Should never reach here — the interrupt check should fire first
-            raise httpx.ConnectError("unexpected retry — interrupt not checked!")
-
-        mock_client = MagicMock()
-        mock_client.chat.completions.create.side_effect = fail_once_then_interrupt
-        mock_create.return_value = mock_client
-
-        agent = _make_agent()
-        agent._interrupt_requested = False
-
-        with pytest.raises(InterruptedError, match="interrupted"):
-            agent._interruptible_streaming_api_call({})
-
-        # Only 1 attempt should have been made — the interrupt should prevent retry
-        assert attempt_count[0] == 1, (
-            f"Expected 1 attempt but got {attempt_count[0]}. "
-            "The retry loop retried despite _interrupt_requested being set."
-        )
-
-    @pytest.mark.filterwarnings(
-        "ignore::pytest.PytestUnhandledThreadExceptionWarning"
-    )
-    @patch("run_agent.AIAgent._create_request_openai_client")
-    @patch("run_agent.AIAgent._close_request_openai_client")
-    def test_interrupt_before_first_attempt(self, mock_close, mock_create):
-        """If _interrupt_requested is already set when the streaming call
-        starts, it should exit immediately without making any API call."""
-        mock_client = MagicMock()
-        mock_create.return_value = mock_client
-
-        agent = _make_agent()
-        agent._interrupt_requested = True  # Pre-set before call
-
-        with pytest.raises(InterruptedError, match="interrupted"):
-            agent._interruptible_streaming_api_call({})
-
-        # No API call should have been made at all
-        assert mock_client.chat.completions.create.call_count == 0
-
-    @patch("run_agent.AIAgent._create_request_openai_client")
-    @patch("run_agent.AIAgent._close_request_openai_client")
-    def test_normal_retry_still_works_without_interrupt(self, mock_close, mock_create):
-        """Without an interrupt, transient errors should still retry normally."""
-        import httpx
-
-        attempts = [0]
-
-        def fail_twice_then_succeed(*args, **kwargs):
-            attempts[0] += 1
-            if attempts[0] <= 2:
-                raise httpx.ConnectError("transient failure")
-            # Third attempt succeeds
-            chunks = [
-                SimpleNamespace(
-                    choices=[
-                        SimpleNamespace(
-                            index=0,
-                            delta=SimpleNamespace(
-                                content="ok",
-                                tool_calls=None,
-                                reasoning_content=None,
-                                reasoning=None,
-                            ),
-                            finish_reason=None,
-                        )
-                    ],
-                    model="test/model",
-                    usage=None,
-                ),
-                SimpleNamespace(
-                    choices=[
-                        SimpleNamespace(
-                            index=0,
-                            delta=SimpleNamespace(
-                                content=None,
-                                tool_calls=None,
-                                reasoning_content=None,
-                                reasoning=None,
-                            ),
-                            finish_reason="stop",
-                        )
-                    ],
-                    model="test/model",
-                    usage=None,
-                ),
-            ]
-            stream = MagicMock()
-            stream.__iter__ = MagicMock(return_value=iter(chunks))
-            stream.response = MagicMock()
-            stream.response.headers = {}
-            return stream
-
-        mock_client = MagicMock()
-        mock_client.chat.completions.create.side_effect = fail_twice_then_succeed
-        mock_create.return_value = mock_client
-
-        agent = _make_agent()
-        agent._interrupt_requested = False
-
-        # Should succeed on the third attempt
-        result = agent._interruptible_streaming_api_call({})
-        assert result is not None
-        assert attempts[0] == 3

tui_gateway/server.py

@@ -712,6 +712,18 @@ def _apply_model_switch(sid: str, session: dict, raw_input: str) -> dict:
         current_base_url = str(runtime.get("base_url", "") or "")
         current_api_key = str(runtime.get("api_key", "") or "")
 
+    # Load user-defined providers so switch_model can resolve named custom
+    # endpoints (e.g. "ollama-launch") and validate against saved model lists.
+    user_provs = None
+    custom_provs = None
+    try:
+        from hermes_cli.config import get_compatible_custom_providers, load_config
+        cfg = load_config()
+        user_provs = [{"provider": k, **v} for k, v in (cfg.get("providers") or {}).items()]
+        custom_provs = get_compatible_custom_providers(cfg)
+    except Exception:
+        pass
+
     result = switch_model(
         raw_input=model_input,
         current_provider=current_provider,
@@ -720,6 +732,8 @@ def _apply_model_switch(sid: str, session: dict, raw_input: str) -> dict:
         current_api_key=current_api_key,
         is_global=persist_global,
         explicit_provider=explicit_provider,
+        user_providers=user_provs,
+        custom_providers=custom_provs,
     )
     if not result.success:
         raise ValueError(result.error_message or "model switch failed")