fix: let the provider decide which chat options a model supports

README.md

@@ -73,7 +73,10 @@ print(response.choices[0].message.content)
 Supported capabilities depend on the selected model and can include streaming,
 tool calls, parallel tool calls, structured outputs and reasoning. The current
 capabilities for each model are shown in the
-[model catalog](https://nexus.dappnode.com/models).
+[model catalog](https://nexus.dappnode.com/models). They describe each model
+and are not checked against chat requests: the selected provider validates chat
+options, so a stale catalog flag cannot reject a request the provider would
+accept. Endpoint routing, privacy policy and credit checks still apply.
 
 ## Privacy and usage controls
 

apps/gateway/internal/application/services/capabilities_test.go

@@ -0,0 +1,24 @@
+package services
+
+import (
+	"testing"
+
+	"github.com/dappnode/dappnode-nexus-gateway/pkg/domain"
+)
+
+func TestStaleCapabilityFlagsDoNotRejectChatOptions(t *testing.T) {
+	parallel := true
+	model := domain.PublicModel{PublicModelID: "fixture", SupportsChatCompletions: true}
+	req := domain.GenerateRequest{Stream: true, Tools: []domain.ToolDefinition{{}}, ParallelToolCalls: &parallel, StructuredOutput: true}
+	if err := (&GenerateService{}).validateRequest(domain.EndpointChatCompletions, req, model); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestSystemOneStillRejectsStreaming(t *testing.T) {
+	model := domain.PublicModel{PublicModelID: "jev", ProviderConfig: domain.ProviderConfig{ProviderName: "typesafe"}}
+	err := (&GenerateService{}).validateRequest(domain.EndpointSystemOne, domain.GenerateRequest{Stream: true}, model)
+	if gwErr, ok := err.(*domain.GatewayError); !ok || gwErr.Code != domain.ErrCodeUnsupportedFeature {
+		t.Fatalf("SystemOne stream = %v", err)
+	}
+}

apps/gateway/internal/application/services/generate_service.go

@@ -187,22 +187,14 @@ func (s *GenerateService) validateRequest(endpoint string, req domain.GenerateRe
 		return domain.ErrUnsupportedEndpoint(model.PublicModelID, endpoint)
 	}
 
-	if req.Stream && !model.SupportsStreamForEndpoint(endpoint) {
+	// Catalog capability flags describe the catalog; they are not a request
+	// schema. Chat options go to the provider unchanged and the provider
+	// decides, so a stale flag cannot reject a request the provider accepts.
+	// SystemOne has no streaming wire protocol in Nexus.
+	if endpoint == domain.EndpointSystemOne && req.Stream {
 		return domain.ErrUnsupportedFeature("streaming for " + endpoint)
 	}
 
-	if len(req.Tools) > 0 && !model.SupportsTools {
-		return domain.ErrUnsupportedFeature("tools")
-	}
-
-	if req.ParallelToolCalls != nil && *req.ParallelToolCalls && !model.SupportsParallelToolCalls {
-		return domain.ErrUnsupportedFeature("parallel_tool_calls")
-	}
-
-	if req.StructuredOutput && !model.SupportsStructuredOutput {
-		return domain.ErrUnsupportedFeature("structured_output")
-	}
-
 	if strings.EqualFold(model.ProviderConfig.ProviderName, "doubleword") && req.ServiceTier != nil {
 		return domain.ErrInvalidField("service_tier is fixed by the selected Doubleword model")
 	}

pkg/domain/domain_test.go

@@ -77,16 +77,3 @@ func TestPublicModelSupportsEndpoint(t *testing.T) {
 		t.Error("should not support unknown")
 	}
 }
-
-func TestPublicModelSupportsStreamForEndpoint(t *testing.T) {
-	m := domain.PublicModel{
-		SupportsChatCompletionsStream: true,
-	}
-	if !m.SupportsStreamForEndpoint(domain.EndpointChatCompletions) {
-		t.Error("should support chat_completions stream")
-	}
-	m.SupportsChatCompletionsStream = false
-	if m.SupportsStreamForEndpoint(domain.EndpointChatCompletions) {
-		t.Error("should not support chat_completions stream when disabled")
-	}
-}

pkg/domain/model.go

@@ -78,16 +78,3 @@ func (m PublicModel) SupportsEndpoint(endpoint string) bool {
 		return false
 	}
 }
-
-// SupportsStreamForEndpoint checks if the model supports streaming for the given endpoint.
-func (m PublicModel) SupportsStreamForEndpoint(endpoint string) bool {
-	if m.ProviderConfig.ProviderName == "typesafe" {
-		return false
-	}
-	switch endpoint {
-	case EndpointChatCompletions:
-		return m.SupportsChatCompletionsStream
-	default:
-		return false
-	}
-}