diff --git a/pkg/agent/loop.go b/pkg/agent/loop.go
index f20a56b9c..c3880b565 100644
--- a/pkg/agent/loop.go
+++ b/pkg/agent/loop.go
@@ -1415,7 +1415,7 @@ 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, resolvedDirectModel(agent.Model, agent.Candidates)
 	}
 
 	_, usedLight, score := agent.Router.SelectModel(userMsg, history, agent.Model)
@@ -1426,7 +1426,7 @@ func (al *AgentLoop) selectCandidates(
 				"score":     score,
 				"threshold": agent.Router.Threshold(),
 			})
-		return agent.Candidates, agent.Model
+		return agent.Candidates, resolvedDirectModel(agent.Model, agent.Candidates)
 	}
 
 	logger.InfoCF("agent", "Model routing: light model selected",
@@ -1436,7 +1436,14 @@ func (al *AgentLoop) selectCandidates(
 			"score":       score,
 			"threshold":   agent.Router.Threshold(),
 		})
-	return agent.LightCandidates, agent.Router.LightModel()
+	return agent.LightCandidates, resolvedDirectModel(agent.Router.LightModel(), agent.LightCandidates)
+}
+
+func resolvedDirectModel(raw string, candidates []providers.FallbackCandidate) string {
+	if len(candidates) == 1 && strings.TrimSpace(candidates[0].Model) != "" {
+		return candidates[0].Model
+	}
+	return raw
 }
 
 // maybeSummarize triggers summarization if the session history exceeds thresholds.
@@ -1728,7 +1735,7 @@ func (al *AgentLoop) retryLLMCall(
 				ctx,
 				[]providers.Message{{Role: "user", Content: prompt}},
 				nil,
-				agent.Model,
+				resolvedDirectModel(agent.Model, agent.Candidates),
 				map[string]any{
 					"max_tokens":       agent.MaxTokens,
 					"temperature":      llmTemperature,
diff --git a/pkg/agent/loop_test.go b/pkg/agent/loop_test.go
index a6604e87f..0b970670f 100644
--- a/pkg/agent/loop_test.go
+++ b/pkg/agent/loop_test.go
@@ -220,6 +220,51 @@ func TestToolRegistry_GetDefinitions(t *testing.T) {
 	}
 }
 
+func TestSelectCandidates_UsesResolvedSingleCandidateModel(t *testing.T) {
+	al := &AgentLoop{}
+	agent := &AgentInstance{
+		ID:    "agent-1",
+		Model: "nemotron-3-nano-30b-a3b",
+		Candidates: []providers.FallbackCandidate{
+			{Provider: "openrouter", Model: "nvidia/nemotron-3-nano-30b-a3b:free"},
+		},
+	}
+
+	candidates, model := al.selectCandidates(agent, "hello", []providers.Message{{Role: "user", Content: "hello"}})
+
+	if len(candidates) != 1 {
+		t.Fatalf("len(candidates) = %d, want 1", len(candidates))
+	}
+	if model != "nvidia/nemotron-3-nano-30b-a3b:free" {
+		t.Fatalf("model = %q, want resolved model", model)
+	}
+}
+
+func TestRetryLLMCall_UsesResolvedSingleCandidateModel(t *testing.T) {
+	provider := &mockProvider{}
+	al := &AgentLoop{}
+	agent := &AgentInstance{
+		ID:        "agent-1",
+		Model:     "nemotron-3-nano-30b-a3b",
+		MaxTokens: 1024,
+		Provider:  provider,
+		Candidates: []providers.FallbackCandidate{
+			{Provider: "openrouter", Model: "nvidia/nemotron-3-nano-30b-a3b:free"},
+		},
+	}
+
+	resp, err := al.retryLLMCall(context.Background(), agent, "hello", 1)
+	if err != nil {
+		t.Fatalf("retryLLMCall() error = %v", err)
+	}
+	if resp == nil {
+		t.Fatal("retryLLMCall() response = nil, want non-nil")
+	}
+	if got := provider.LastModel(); got != "nvidia/nemotron-3-nano-30b-a3b:free" {
+		t.Fatalf("provider model = %q, want resolved model", got)
+	}
+}
+
 // TestAgentLoop_GetStartupInfo verifies startup info contains tools
 func TestAgentLoop_GetStartupInfo(t *testing.T) {
 	tmpDir, err := os.MkdirTemp("", "agent-test-*")
diff --git a/pkg/agent/mock_provider_test.go b/pkg/agent/mock_provider_test.go
index 4962810dc..61e184248 100644
--- a/pkg/agent/mock_provider_test.go
+++ b/pkg/agent/mock_provider_test.go
@@ -2,11 +2,15 @@ package agent
 
 import (
 	"context"
+	"sync"
 
 	"github.com/sipeed/picoclaw/pkg/providers"
 )
 
-type mockProvider struct{}
+type mockProvider struct {
+	mu        sync.Mutex
+	lastModel string
+}
 
 func (m *mockProvider) Chat(
 	ctx context.Context,
@@ -15,6 +19,9 @@ func (m *mockProvider) Chat(
 	model string,
 	opts map[string]any,
 ) (*providers.LLMResponse, error) {
+	m.mu.Lock()
+	m.lastModel = model
+	m.mu.Unlock()
 	return &providers.LLMResponse{
 		Content:   "Mock response",
 		ToolCalls: []providers.ToolCall{},
@@ -24,3 +31,9 @@ func (m *mockProvider) Chat(
 func (m *mockProvider) GetDefaultModel() string {
 	return "mock-model"
 }
+
+func (m *mockProvider) LastModel() string {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return m.lastModel
+}