Merge branch 'upstream-main' into feat/subturn-poc

pkg/agent/loop.go

@@ -1760,7 +1760,7 @@ func (al *AgentLoop) selectCandidates(
 	history []providers.Message,
 ) (candidates []providers.FallbackCandidate, model string) {
 	if agent.Router == nil || len(agent.LightCandidates) == 0 {
-		return agent.Candidates, agent.Model
+		return agent.Candidates, resolvedCandidateModel(agent.Candidates, agent.Model)
 	}
 
 	_, usedLight, score := agent.Router.SelectModel(userMsg, history, agent.Model)
@@ -1771,7 +1771,7 @@ func (al *AgentLoop) selectCandidates(
 				"score":     score,
 				"threshold": agent.Router.Threshold(),
 			})
-		return agent.Candidates, agent.Model
+		return agent.Candidates, resolvedCandidateModel(agent.Candidates, agent.Model)
 	}
 
 	logger.InfoCF("agent", "Model routing: light model selected",
@@ -1781,7 +1781,7 @@ func (al *AgentLoop) selectCandidates(
 			"score":       score,
 			"threshold":   agent.Router.Threshold(),
 		})
-	return agent.LightCandidates, agent.Router.LightModel()
+	return agent.LightCandidates, resolvedCandidateModel(agent.LightCandidates, agent.Router.LightModel())
 }
 
 // maybeSummarize triggers summarization if the session history exceeds thresholds.
@@ -2271,11 +2271,37 @@ func (al *AgentLoop) buildCommandsRuntime(agent *AgentInstance, opts *processOpt
 	}
 	if agent != nil {
 		rt.GetModelInfo = func() (string, string) {
-			return agent.Model, cfg.Agents.Defaults.Provider
+			return agent.Model, resolvedCandidateProvider(agent.Candidates, cfg.Agents.Defaults.Provider)
 		}
 		rt.SwitchModel = func(value string) (string, error) {
+			value = strings.TrimSpace(value)
+			modelCfg, err := resolvedModelConfig(cfg, value, agent.Workspace)
+			if err != nil {
+				return "", err
+			}
+
+			nextProvider, _, err := providers.CreateProviderFromConfig(modelCfg)
+			if err != nil {
+				return "", fmt.Errorf("failed to initialize model %q: %w", value, err)
+			}
+
+			nextCandidates := resolveModelCandidates(cfg, cfg.Agents.Defaults.Provider, modelCfg.Model, agent.Fallbacks)
+			if len(nextCandidates) == 0 {
+				return "", fmt.Errorf("model %q did not resolve to any provider candidates", value)
+			}
+
 			oldModel := agent.Model
+			oldProvider := agent.Provider
 			agent.Model = value
+			agent.Provider = nextProvider
+			agent.Candidates = nextCandidates
+			agent.ThinkingLevel = parseThinkingLevel(modelCfg.ThinkingLevel)
+
+			if oldProvider != nil && oldProvider != nextProvider {
+				if stateful, ok := oldProvider.(providers.StatefulProvider); ok {
+					stateful.Close()
+				}
+			}
 			return oldModel, nil
 		}