Merge pull request #2982 from loafoe/fix/bedrock-opus48-temperature

fix(bedrock): drop temperature for models that deprecate it (Opus 4.8)

pkg/providers/bedrock/provider_bedrock.go

@@ -143,7 +143,22 @@ type converseParams struct {
 	toolConfig      *types.ToolConfiguration
 }
 
-func buildConverseParams(messages []Message, tools []ToolDefinition, options map[string]any) converseParams {
+// modelDeprecatesTemperature reports whether the given Bedrock model rejects the
+// temperature inference parameter. Newer Claude models (Opus 4.8 and later) treat
+// temperature as deprecated and return a ValidationException if it is supplied:
+//
+//	ValidationException: The model returned the following errors:
+//	temperature is deprecated for this model.
+//
+// The match is intentionally loose: Bedrock model IDs and inference-profile ARNs
+// embed the model name (e.g. "us.anthropic.claude-opus-4-8-20260514-v1:0"), so a
+// substring check covers both bare IDs and region-prefixed inference profiles.
+func modelDeprecatesTemperature(model string) bool {
+	m := strings.ToLower(model)
+	return strings.Contains(m, "claude-opus-4-8")
+}
+
+func buildConverseParams(messages []Message, tools []ToolDefinition, model string, options map[string]any) converseParams {
 	bedrockMessages, systemPrompts := convertMessages(messages)
 
 	var inferenceConfig *types.InferenceConfiguration
@@ -159,10 +174,14 @@ func buildConverseParams(messages []Message, tools []ToolDefinition, options map
 	}
 
 	if temp, ok := common.AsFloat(options["temperature"]); ok {
-		if inferenceConfig == nil {
+		if modelDeprecatesTemperature(model) {
-			inferenceConfig = &types.InferenceConfiguration{}
+			log.Printf("bedrock: temperature dropped because model %q no longer supports it", model)
+		} else {
+			if inferenceConfig == nil {
+				inferenceConfig = &types.InferenceConfiguration{}
+			}
+			inferenceConfig.Temperature = aws.Float32(float32(temp))
 		}
-		inferenceConfig.Temperature = aws.Float32(float32(temp))
 	}
 
 	var toolConfig *types.ToolConfiguration
@@ -199,7 +218,7 @@ func (p *Provider) Chat(
 		defer cancel()
 	}
 
-	params := buildConverseParams(messages, tools, options)
+	params := buildConverseParams(messages, tools, model, options)
 	input := &bedrockruntime.ConverseInput{
 		ModelId:         aws.String(model),
 		Messages:        params.messages,
@@ -242,7 +261,7 @@ func (p *Provider) ChatStream(
 		}
 	}
 
-	params := buildConverseParams(messages, tools, options)
+	params := buildConverseParams(messages, tools, model, options)
 	input := &bedrockruntime.ConverseStreamInput{
 		ModelId:         aws.String(model),
 		Messages:        params.messages,

pkg/providers/bedrock/provider_bedrock_test.go

@@ -875,3 +875,49 @@ func TestParseStreamResponse_StopReasons(t *testing.T) {
 		})
 	}
 }
+
+func TestModelDeprecatesTemperature(t *testing.T) {
+	tests := []struct {
+		name  string
+		model string
+		want  bool
+	}{
+		{"opus 4.8 bare id", "claude-opus-4-8-20260514-v1:0", true},
+		{"opus 4.8 inference profile", "us.anthropic.claude-opus-4-8-20260514-v1:0", true},
+		{"opus 4.8 mixed case", "US.Anthropic.Claude-Opus-4-8", true},
+		{"opus 4.7 unaffected", "us.anthropic.claude-opus-4-7-20250101-v1:0", false},
+		{"sonnet unaffected", "us.anthropic.claude-sonnet-4-6", false},
+		{"empty", "", false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, modelDeprecatesTemperature(tt.model))
+		})
+	}
+}
+
+func TestBuildConverseParams_DropsTemperatureForDeprecatedModel(t *testing.T) {
+	options := map[string]any{
+		"temperature": 0.7,
+		"max_tokens":  1024,
+	}
+
+	params := buildConverseParams(nil, nil, "us.anthropic.claude-opus-4-8-20260514-v1:0", options)
+
+	require.NotNil(t, params.inferenceConfig, "max_tokens should still populate inference config")
+	assert.Nil(t, params.inferenceConfig.Temperature, "temperature must be omitted for opus 4.8")
+	require.NotNil(t, params.inferenceConfig.MaxTokens)
+	assert.Equal(t, int32(1024), *params.inferenceConfig.MaxTokens)
+}
+
+func TestBuildConverseParams_KeepsTemperatureForSupportedModel(t *testing.T) {
+	options := map[string]any{
+		"temperature": 0.7,
+	}
+
+	params := buildConverseParams(nil, nil, "us.anthropic.claude-opus-4-7-20250101-v1:0", options)
+
+	require.NotNil(t, params.inferenceConfig)
+	require.NotNil(t, params.inferenceConfig.Temperature)
+	assert.InDelta(t, 0.7, float64(*params.inferenceConfig.Temperature), 0.0001)
+}