diff --git a/pkg/agent/instance.go b/pkg/agent/instance.go
index 54a5396e7..a992945fa 100644
--- a/pkg/agent/instance.go
+++ b/pkg/agent/instance.go
@@ -21,6 +21,8 @@ type AgentInstance struct {
 	Fallbacks      []string
 	Workspace      string
 	MaxIterations  int
+	MaxTokens      int
+	Temperature    float64
 	ContextWindow  int
 	Provider       providers.LLMProvider
 	Sessions       *session.SessionManager
@@ -76,6 +78,11 @@ func NewAgentInstance(
 		maxIter = 20
 	}
 
+	maxTokens := defaults.MaxTokens
+	if maxTokens == 0 {
+		maxTokens = 8192
+	}
+
 	// Resolve fallback candidates
 	modelCfg := providers.ModelConfig{
 		Primary:   model,
@@ -90,7 +97,9 @@ func NewAgentInstance(
 		Fallbacks:      fallbacks,
 		Workspace:      workspace,
 		MaxIterations:  maxIter,
-		ContextWindow:  defaults.MaxTokens,
+		MaxTokens:      maxTokens,
+		Temperature:    defaults.Temperature,
+		ContextWindow:  maxTokens,
 		Provider:       provider,
 		Sessions:       sessionsManager,
 		ContextBuilder: contextBuilder,
diff --git a/pkg/agent/instance_test.go b/pkg/agent/instance_test.go
new file mode 100644
index 000000000..2500d1d88
--- /dev/null
+++ b/pkg/agent/instance_test.go
@@ -0,0 +1,38 @@
+package agent
+
+import (
+	"os"
+	"testing"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+)
+
+func TestNewAgentInstance_UsesDefaultsTemperatureAndMaxTokens(t *testing.T) {
+	tmpDir, err := os.MkdirTemp("", "agent-instance-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,
+				Model:             "test-model",
+				MaxTokens:         1234,
+				Temperature:       1.0,
+				MaxToolIterations: 5,
+			},
+		},
+	}
+
+	provider := &mockProvider{}
+	agent := NewAgentInstance(nil, &cfg.Agents.Defaults, cfg, provider)
+
+	if agent.MaxTokens != 1234 {
+		t.Fatalf("MaxTokens = %d, want %d", agent.MaxTokens, 1234)
+	}
+	if agent.Temperature != 1.0 {
+		t.Fatalf("Temperature = %f, want %f", agent.Temperature, 1.0)
+	}
+}
diff --git a/pkg/agent/loop.go b/pkg/agent/loop.go
index 6d0a61375..593442ac5 100644
--- a/pkg/agent/loop.go
+++ b/pkg/agent/loop.go
@@ -470,8 +470,8 @@ func (al *AgentLoop) runLLMIteration(ctx context.Context, agent *AgentInstance,
 				"model":             agent.Model,
 				"messages_count":    len(messages),
 				"tools_count":       len(providerToolDefs),
-				"max_tokens":        8192,
-				"temperature":       0.7,
+				"max_tokens":        agent.MaxTokens,
+				"temperature":       agent.Temperature,
 				"system_prompt_len": len(messages[0].Content),
 			})
 
@@ -492,8 +492,8 @@ func (al *AgentLoop) runLLMIteration(ctx context.Context, agent *AgentInstance,
 				fbResult, fbErr := al.fallback.Execute(ctx, agent.Candidates,
 					func(ctx context.Context, provider, model string) (*providers.LLMResponse, error) {
 						return agent.Provider.Chat(ctx, messages, providerToolDefs, model, map[string]interface{}{
-							"max_tokens":  8192,
-							"temperature": 0.7,
+							"max_tokens":  agent.MaxTokens,
+							"temperature": agent.Temperature,
 						})
 					},
 				)
@@ -508,8 +508,8 @@ func (al *AgentLoop) runLLMIteration(ctx context.Context, agent *AgentInstance,
 				return fbResult.Response, nil
 			}
 			return agent.Provider.Chat(ctx, messages, providerToolDefs, agent.Model, map[string]interface{}{
-				"max_tokens":  8192,
-				"temperature": 0.7,
+				"max_tokens":  agent.MaxTokens,
+				"temperature": agent.Temperature,
 			})
 		}