fix(studio): read an alias's model settings from its target

The chat harness took the context window, agent options and input
modalities from the config of the name a chat asked for. An alias has
no model of its own and the loader gives it the generic default
window, so a chat on an alias budgeted against 4096 tokens and failed
on tool schemas even when the target ran with a far larger window.
Resolve the alias to its target first, as the capabilities endpoint
already does.

Assisted-by: Claude Code:claude-sonnet-5-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

core/application/studio_service.go

@@ -314,10 +314,19 @@ func (a *Application) loadStudioUser(ctx context.Context, id string) (*auth.User
 	return &u, nil
 }
 
+// studioModelConfig is the config of the model that serves a name. An alias is
+// a redirect whose own config carries no model settings (the loader gives it the
+// generic default window), so the settings come from its target.
+func (a *Application) studioModelConfig(model string) (config.ModelConfig, bool) {
+	bcl := a.ModelConfigLoader()
+	name, _ := bcl.ResolveAliasName(model)
+	return bcl.GetModelConfig(name)
+}
+
 // studioContextTokens is the context window of a model, or zero when its config
 // does not say.
 func (a *Application) studioContextTokens(model string) int {
-	cfg, ok := a.ModelConfigLoader().GetModelConfig(model)
+	cfg, ok := a.studioModelConfig(model)
 	if !ok || cfg.ContextSize == nil {
 		return 0
 	}
@@ -327,7 +336,7 @@ func (a *Application) studioContextTokens(model string) int {
 // studioModalities says which inputs a chat model takes natively, from its
 // configuration. An unknown model takes none.
 func (a *Application) studioModalities(model string) studio.Modalities {
-	cfg, ok := a.ModelConfigLoader().GetModelConfig(model)
+	cfg, ok := a.studioModelConfig(model)
 	if !ok {
 		return studio.Modalities{}
 	}
@@ -340,7 +349,7 @@ func (a *Application) studioModalities(model string) studio.Modalities {
 // limit is the model's agent.max_iterations, else chats_max_iterations.
 func (a *Application) studioAgentOptions(model string) nibharness.AgentOptions {
 	opts := nibharness.AgentOptions{Iterations: a.applicationConfig.EffectiveChatsMaxIterations()}
-	cfg, ok := a.ModelConfigLoader().GetModelConfig(model)
+	cfg, ok := a.studioModelConfig(model)
 	if !ok {
 		return opts
 	}

core/application/studio_service_test.go

@@ -93,6 +93,27 @@ var _ = Describe("studio service at startup", func() {
 		Expect(app.studioContextTokens("missing")).To(Equal(0))
 	})
 
+	It("reads the window of an alias from its target, not from the alias", func() {
+		app := newApp()
+		big, fallback := 100096, 4096
+		app.ModelConfigLoader().ReplaceModelConfigs([]config.ModelConfig{
+			{Name: "target-model", LLMConfig: config.LLMConfig{ContextSize: &big}},
+			// The loader gives every alias the generic default window.
+			{Name: "default", Alias: "target-model", LLMConfig: config.LLMConfig{ContextSize: &fallback}},
+		})
+		Expect(app.studioContextTokens("default")).To(Equal(100096))
+		Expect(app.studioContextTokens("target-model")).To(Equal(100096))
+	})
+
+	It("reads the agent options of an alias from its target", func() {
+		app := newApp()
+		app.ModelConfigLoader().ReplaceModelConfigs([]config.ModelConfig{
+			{Name: "target-model", Agent: config.AgentConfig{MaxIterations: 7}},
+			{Name: "default", Alias: "target-model"},
+		})
+		Expect(app.studioAgentOptions("default").Iterations).To(Equal(7))
+	})
+
 	Describe("MCP servers of a chat", func() {
 		servers := "mcpServers:\n  crm:\n    url: http://127.0.0.1:1/crm\n  mail:\n    url: http://127.0.0.1:1/mail\n"