fix(agent): rebind provider after /switch model to (#1769)

* fix(agent): rebind provider after model switch

* test(agent): deduplicate switch model mock servers

---------

Co-authored-by: Alix-007 <267018309+Alix-007@users.noreply.github.com>

pkg/agent/instance.go

@@ -152,59 +152,14 @@ func NewAgentInstance(
 	}
 
 	// Resolve fallback candidates
-	modelCfg := providers.ModelConfig{
+	candidates := resolveModelCandidates(cfg, defaults.Provider, model, fallbacks)
-		Primary:   model,
-		Fallbacks: fallbacks,
-	}
-	resolveFromModelList := func(raw string) (string, bool) {
-		ensureProtocol := func(model string) string {
-			model = strings.TrimSpace(model)
-			if model == "" {
-				return ""
-			}
-			if strings.Contains(model, "/") {
-				return model
-			}
-			return "openai/" + model
-		}
-
-		raw = strings.TrimSpace(raw)
-		if raw == "" {
-			return "", false
-		}
-
-		if cfg != nil {
-			if mc, err := cfg.GetModelConfig(raw); err == nil && mc != nil && strings.TrimSpace(mc.Model) != "" {
-				return ensureProtocol(mc.Model), true
-			}
-
-			for i := range cfg.ModelList {
-				fullModel := strings.TrimSpace(cfg.ModelList[i].Model)
-				if fullModel == "" {
-					continue
-				}
-				if fullModel == raw {
-					return ensureProtocol(fullModel), true
-				}
-				_, modelID := providers.ExtractProtocol(fullModel)
-				if modelID == raw {
-					return ensureProtocol(fullModel), true
-				}
-			}
-		}
-
-		return "", false
-	}
-
-	candidates := providers.ResolveCandidatesWithLookup(modelCfg, defaults.Provider, resolveFromModelList)
 
 	// Model routing setup: pre-resolve light model candidates at creation time
 	// to avoid repeated model_list lookups on every incoming message.
 	var router *routing.Router
 	var lightCandidates []providers.FallbackCandidate
 	if rc := defaults.Routing; rc != nil && rc.Enabled && rc.LightModel != "" {
-		lightModelCfg := providers.ModelConfig{Primary: rc.LightModel}
+		resolved := resolveModelCandidates(cfg, defaults.Provider, rc.LightModel, nil)
-		resolved := providers.ResolveCandidatesWithLookup(lightModelCfg, defaults.Provider, resolveFromModelList)
 		if len(resolved) > 0 {
 			router = routing.New(routing.RouterConfig{
 				LightModel: rc.LightModel,

pkg/agent/loop.go

@@ -1477,7 +1477,7 @@ 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)
@@ -1488,7 +1488,7 @@ 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",
@@ -1498,7 +1498,7 @@ 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.
@@ -1961,11 +1961,37 @@ 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
 		}
 

pkg/agent/loop_test.go

@@ -2,7 +2,10 @@ package agent
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"path/filepath"
 	"slices"
@@ -444,6 +447,46 @@ type testHelper struct {
 	al *AgentLoop
 }
 
+func newChatCompletionTestServer(
+	t *testing.T,
+	label string,
+	response string,
+	calls *int,
+	model *string,
+) *httptest.Server {
+	t.Helper()
+
+	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/chat/completions" {
+			t.Fatalf("%s server path = %q, want /chat/completions", label, r.URL.Path)
+		}
+		*calls = *calls + 1
+		defer r.Body.Close()
+
+		var req struct {
+			Model string `json:"model"`
+		}
+		decodeErr := json.NewDecoder(r.Body).Decode(&req)
+		if decodeErr != nil {
+			t.Fatalf("decode %s request: %v", label, decodeErr)
+		}
+		*model = req.Model
+
+		w.Header().Set("Content-Type", "application/json")
+		encodeErr := json.NewEncoder(w).Encode(map[string]any{
+			"choices": []map[string]any{
+				{
+					"message":       map[string]any{"content": response},
+					"finish_reason": "stop",
+				},
+			},
+		})
+		if encodeErr != nil {
+			t.Fatalf("encode %s response: %v", label, encodeErr)
+		}
+	}))
+}
+
 func (h testHelper) executeAndGetResponse(tb testing.TB, ctx context.Context, msg bus.InboundMessage) string {
 	// Use a short timeout to avoid hanging
 	timeoutCtx, cancel := context.WithTimeout(ctx, responseTimeout)
@@ -605,11 +648,25 @@ func TestProcessMessage_SwitchModelShowModelConsistency(t *testing.T) {
 			Defaults: config.AgentDefaults{
 				Workspace:         tmpDir,
 				Provider:          "openai",
-				Model:             "before-switch",
+				Model:             "local",
 				MaxTokens:         4096,
 				MaxToolIterations: 10,
 			},
 		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "local",
+				Model:     "openai/local-model",
+				APIKey:    "test-key",
+				APIBase:   "https://local.example.invalid/v1",
+			},
+			{
+				ModelName: "deepseek",
+				Model:     "openrouter/deepseek/deepseek-v3.2",
+				APIKey:    "test-key",
+				APIBase:   "https://openrouter.ai/api/v1",
+			},
+		},
 	}
 
 	msgBus := bus.NewMessageBus()
@@ -621,13 +678,13 @@ func TestProcessMessage_SwitchModelShowModelConsistency(t *testing.T) {
 		Channel:  "telegram",
 		SenderID: "user1",
 		ChatID:   "chat1",
-		Content:  "/switch model to after-switch",
+		Content:  "/switch model to deepseek",
 		Peer: bus.Peer{
 			Kind: "direct",
 			ID:   "user1",
 		},
 	})
-	if !strings.Contains(switchResp, "Switched model from before-switch to after-switch") {
+	if !strings.Contains(switchResp, "Switched model from local to deepseek") {
 		t.Fatalf("unexpected /switch reply: %q", switchResp)
 	}
 
@@ -641,7 +698,7 @@ func TestProcessMessage_SwitchModelShowModelConsistency(t *testing.T) {
 			ID:   "user1",
 		},
 	})
-	if !strings.Contains(showResp, "Current Model: after-switch (Provider: openai)") {
+	if !strings.Contains(showResp, "Current Model: deepseek (Provider: openrouter)") {
 		t.Fatalf("unexpected /show model reply after switch: %q", showResp)
 	}
 
@@ -650,6 +707,187 @@ func TestProcessMessage_SwitchModelShowModelConsistency(t *testing.T) {
 	}
 }
 
+func TestProcessMessage_SwitchModelRejectsUnknownAlias(t *testing.T) {
+	tmpDir, err := os.MkdirTemp("", "agent-test-*")
+	if err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				Workspace:         tmpDir,
+				Provider:          "openai",
+				Model:             "local",
+				MaxTokens:         4096,
+				MaxToolIterations: 10,
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "local",
+				Model:     "openai/local-model",
+				APIKey:    "test-key",
+				APIBase:   "https://local.example.invalid/v1",
+			},
+		},
+	}
+
+	msgBus := bus.NewMessageBus()
+	provider := &countingMockProvider{response: "LLM reply"}
+	al := NewAgentLoop(cfg, msgBus, provider)
+	helper := testHelper{al: al}
+
+	switchResp := helper.executeAndGetResponse(t, context.Background(), bus.InboundMessage{
+		Channel:  "telegram",
+		SenderID: "user1",
+		ChatID:   "chat1",
+		Content:  "/switch model to missing",
+		Peer: bus.Peer{
+			Kind: "direct",
+			ID:   "user1",
+		},
+	})
+	if switchResp != `model "missing" not found in model_list or providers` {
+		t.Fatalf("unexpected /switch error reply: %q", switchResp)
+	}
+
+	showResp := helper.executeAndGetResponse(t, context.Background(), bus.InboundMessage{
+		Channel:  "telegram",
+		SenderID: "user1",
+		ChatID:   "chat1",
+		Content:  "/show model",
+		Peer: bus.Peer{
+			Kind: "direct",
+			ID:   "user1",
+		},
+	})
+	if !strings.Contains(showResp, "Current Model: local (Provider: openai)") {
+		t.Fatalf("unexpected /show model reply after rejected switch: %q", showResp)
+	}
+
+	if provider.calls != 0 {
+		t.Fatalf("LLM should not be called for rejected /switch and /show, calls=%d", provider.calls)
+	}
+}
+
+func TestProcessMessage_SwitchModelRoutesSubsequentRequestsToSelectedProvider(t *testing.T) {
+	tmpDir, err := os.MkdirTemp("", "agent-test-*")
+	if err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	localCalls := 0
+	localModel := ""
+	localServer := newChatCompletionTestServer(t, "local", "local reply", &localCalls, &localModel)
+	defer localServer.Close()
+
+	remoteCalls := 0
+	remoteModel := ""
+	remoteServer := newChatCompletionTestServer(t, "remote", "remote reply", &remoteCalls, &remoteModel)
+	defer remoteServer.Close()
+
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				Workspace:         tmpDir,
+				Provider:          "openai",
+				Model:             "local",
+				MaxTokens:         4096,
+				MaxToolIterations: 10,
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "local",
+				Model:     "openai/Qwen3.5-35B-A3B",
+				APIKey:    "local-key",
+				APIBase:   localServer.URL,
+			},
+			{
+				ModelName: "deepseek",
+				Model:     "openrouter/deepseek/deepseek-v3.2",
+				APIKey:    "remote-key",
+				APIBase:   remoteServer.URL,
+			},
+		},
+	}
+
+	msgBus := bus.NewMessageBus()
+	provider, _, err := providers.CreateProvider(cfg)
+	if err != nil {
+		t.Fatalf("CreateProvider() error = %v", err)
+	}
+	al := NewAgentLoop(cfg, msgBus, provider)
+	helper := testHelper{al: al}
+
+	firstResp := helper.executeAndGetResponse(t, context.Background(), bus.InboundMessage{
+		Channel:  "telegram",
+		SenderID: "user1",
+		ChatID:   "chat1",
+		Content:  "hello before switch",
+		Peer: bus.Peer{
+			Kind: "direct",
+			ID:   "user1",
+		},
+	})
+	if firstResp != "local reply" {
+		t.Fatalf("unexpected response before switch: %q", firstResp)
+	}
+	if localCalls != 1 {
+		t.Fatalf("local calls before switch = %d, want 1", localCalls)
+	}
+	if remoteCalls != 0 {
+		t.Fatalf("remote calls before switch = %d, want 0", remoteCalls)
+	}
+	if localModel != "Qwen3.5-35B-A3B" {
+		t.Fatalf("local model before switch = %q, want %q", localModel, "Qwen3.5-35B-A3B")
+	}
+
+	switchResp := helper.executeAndGetResponse(t, context.Background(), bus.InboundMessage{
+		Channel:  "telegram",
+		SenderID: "user1",
+		ChatID:   "chat1",
+		Content:  "/switch model to deepseek",
+		Peer: bus.Peer{
+			Kind: "direct",
+			ID:   "user1",
+		},
+	})
+	if !strings.Contains(switchResp, "Switched model from local to deepseek") {
+		t.Fatalf("unexpected /switch reply: %q", switchResp)
+	}
+
+	secondResp := helper.executeAndGetResponse(t, context.Background(), bus.InboundMessage{
+		Channel:  "telegram",
+		SenderID: "user1",
+		ChatID:   "chat1",
+		Content:  "hello after switch",
+		Peer: bus.Peer{
+			Kind: "direct",
+			ID:   "user1",
+		},
+	})
+	if secondResp != "remote reply" {
+		t.Fatalf("unexpected response after switch: %q", secondResp)
+	}
+	if localCalls != 1 {
+		t.Fatalf("local calls after switch = %d, want 1", localCalls)
+	}
+	if remoteCalls != 1 {
+		t.Fatalf("remote calls after switch = %d, want 1", remoteCalls)
+	}
+	if remoteModel != "deepseek-v3.2" {
+		t.Fatalf(
+			"remote model after switch = %q, want %q",
+			remoteModel,
+			"deepseek-v3.2",
+		)
+	}
+}
+
 // TestToolResult_SilentToolDoesNotSendUserMessage verifies silent tools don't trigger outbound
 func TestToolResult_SilentToolDoesNotSendUserMessage(t *testing.T) {
 	tmpDir, err := os.MkdirTemp("", "agent-test-*")

pkg/agent/model_resolution.go

@@ -0,0 +1,97 @@
+package agent
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/providers"
+)
+
+func buildModelListResolver(cfg *config.Config) func(raw string) (string, bool) {
+	ensureProtocol := func(model string) string {
+		model = strings.TrimSpace(model)
+		if model == "" {
+			return ""
+		}
+		if strings.Contains(model, "/") {
+			return model
+		}
+		return "openai/" + model
+	}
+
+	return func(raw string) (string, bool) {
+		raw = strings.TrimSpace(raw)
+		if raw == "" || cfg == nil {
+			return "", false
+		}
+
+		if mc, err := cfg.GetModelConfig(raw); err == nil && mc != nil && strings.TrimSpace(mc.Model) != "" {
+			return ensureProtocol(mc.Model), true
+		}
+
+		for i := range cfg.ModelList {
+			fullModel := strings.TrimSpace(cfg.ModelList[i].Model)
+			if fullModel == "" {
+				continue
+			}
+			if fullModel == raw {
+				return ensureProtocol(fullModel), true
+			}
+			_, modelID := providers.ExtractProtocol(fullModel)
+			if modelID == raw {
+				return ensureProtocol(fullModel), true
+			}
+		}
+
+		return "", false
+	}
+}
+
+func resolveModelCandidates(
+	cfg *config.Config,
+	defaultProvider string,
+	primary string,
+	fallbacks []string,
+) []providers.FallbackCandidate {
+	return providers.ResolveCandidatesWithLookup(
+		providers.ModelConfig{
+			Primary:   primary,
+			Fallbacks: fallbacks,
+		},
+		defaultProvider,
+		buildModelListResolver(cfg),
+	)
+}
+
+func resolvedCandidateModel(candidates []providers.FallbackCandidate, fallback string) string {
+	if len(candidates) > 0 && strings.TrimSpace(candidates[0].Model) != "" {
+		return candidates[0].Model
+	}
+	return fallback
+}
+
+func resolvedCandidateProvider(candidates []providers.FallbackCandidate, fallback string) string {
+	if len(candidates) > 0 && strings.TrimSpace(candidates[0].Provider) != "" {
+		return candidates[0].Provider
+	}
+	return fallback
+}
+
+func resolvedModelConfig(cfg *config.Config, modelName, workspace string) (*config.ModelConfig, error) {
+	if cfg == nil {
+		return nil, fmt.Errorf("config is nil")
+	}
+
+	modelCfg, err := cfg.GetModelConfig(strings.TrimSpace(modelName))
+	if err != nil {
+		return nil, err
+	}
+
+	clone := *modelCfg
+	if clone.Workspace == "" {
+		clone.Workspace = workspace
+	}
+
+	return &clone, nil
+}