Add checks for deployment model name

pkg/providers/azure/provider.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 
@@ -87,9 +88,13 @@ func (p *Provider) Chat(
 	// model is the deployment name for Azure OpenAI
 	deployment := model
 
-	// Build Azure-specific URL: {base}/openai/deployments/{deployment}/chat/completions?api-version=...
+	// Build Azure-specific URL safely using url.JoinPath and query encoding
-	requestURL := fmt.Sprintf("%s/openai/deployments/%s/chat/completions?api-version=%s",
+	// to prevent path traversal or query injection via deployment names.
-		p.apiBase, deployment, azureAPIVersion)
+	base, err := url.JoinPath(p.apiBase, "openai/deployments", deployment, "chat/completions")
+	if err != nil {
+		return nil, fmt.Errorf("failed to build Azure request URL: %w", err)
+	}
+	requestURL := base + "?api-version=" + azureAPIVersion
 
 	// Build request body — no "model" field (Azure infers from deployment URL)
 	requestBody := map[string]any{

pkg/providers/azure/provider_test.go

@@ -204,3 +204,29 @@ func TestProvider_AzureNewProviderWithTimeout(t *testing.T) {
 		t.Errorf("timeout = %v, want %v", p.httpClient.Timeout, 180*time.Second)
 	}
 }
+
+func TestProviderChat_AzureDeploymentNameEscaped(t *testing.T) {
+	var capturedPath string
+
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		capturedPath = r.URL.RawPath // use RawPath to see percent-encoding
+		if capturedPath == "" {
+			capturedPath = r.URL.Path
+		}
+		writeValidResponse(w)
+	}))
+	defer server.Close()
+
+	p := NewProvider("test-key", server.URL, "")
+
+	// Deployment name with characters that could cause path injection
+	_, err := p.Chat(t.Context(), []Message{{Role: "user", Content: "hi"}}, nil, "my deploy/../../admin", nil)
+	if err != nil {
+		t.Fatalf("Chat() error = %v", err)
+	}
+
+	// The slash and special chars in the deployment name must be escaped, not treated as path separators
+	if capturedPath == "/openai/deployments/my deploy/../../admin/chat/completions" {
+		t.Fatal("deployment name was interpolated without escaping — path injection possible")
+	}
+}