feat: support passing image URL directly to vision providers in read_image tool

internal/providers/openai_request.go

@@ -74,10 +74,14 @@ func (p *OpenAIProvider) buildRequestBody(model string, req ChatRequest, stream
 				})
 			}
 			for _, img := range m.Images {
+				urlVal := img.URL
+				if urlVal == "" {
+					urlVal = fmt.Sprintf("data:%s;base64,%s", img.MimeType, img.Data)
+				}
 				parts = append(parts, map[string]any{
 					"type": "image_url",
 					"image_url": map[string]any{
-						"url": fmt.Sprintf("data:%s;base64,%s", img.MimeType, img.Data),
+						"url": urlVal,
 					},
 				})
 			}

internal/providers/openai_test.go

@@ -240,6 +240,31 @@ func TestBuildRequestBody_MultimodalTextBeforeImages(t *testing.T) {
 	}
 }
 
+func TestBuildRequestBody_MultimodalWithImageURL(t *testing.T) {
+	p := NewOpenAIProvider("test", "key", "https://api.openai.com/v1", "gpt-4")
+	req := ChatRequest{
+		Messages: []Message{
+			{
+				Role:    "user",
+				Content: "describe",
+				Images: []ImageContent{
+					{URL: "https://example.com/image.png"},
+				},
+			},
+		},
+	}
+	body := p.buildRequestBody("gpt-4o", req, false)
+	msgs := body["messages"].([]map[string]any)
+	parts, ok := msgs[0]["content"].([]map[string]any)
+	if !ok || len(parts) < 2 {
+		t.Fatalf("want multimodal parts, got %v", msgs[0]["content"])
+	}
+	imgPart := parts[1]["image_url"].(map[string]any)
+	if urlVal, _ := imgPart["url"].(string); urlVal != "https://example.com/image.png" {
+		t.Errorf("expected URL to be https://example.com/image.png, got %q", urlVal)
+	}
+}
+
 func TestBuildRequestBody_TogetherDetectedByProviderType(t *testing.T) {
 	// Together behind reverse proxy — detected by providerType, not URL.
 	p := NewOpenAIProvider("my-proxy", "key", "https://proxy.internal/v1", "")

internal/providers/types.go

@@ -113,10 +113,11 @@ type StreamChunk struct {
 	Images   []ImageContent `json:"images,omitempty"` // image generation frames (Codex)
 }
 
-// ImageContent represents a base64-encoded image for vision-capable models.
+// ImageContent represents an image (either base64-encoded or a direct URL) for vision-capable models.
 type ImageContent struct {
 	MimeType string `json:"mime_type"`         // e.g. "image/jpeg"
 	Data     string `json:"data"`              // base64-encoded image bytes
+	URL      string `json:"url,omitempty"`     // URL of the image
 	Partial  bool   `json:"partial,omitempty"` // true for intermediate frames (Codex image_generation_call)
 }
 

internal/tools/read_image.go

@@ -77,6 +77,10 @@ func (t *ReadImageTool) Parameters() map[string]any {
 				"type":        "string",
 				"description": "Optional file path to an image in the workspace. Use this for generated images or attachments. If omitted, analyzes images from the conversation.",
 			},
+			"url": map[string]any{
+				"type":        "string",
+				"description": "Optional URL to an image. Use this to analyze images hosted online.",
+			},
 		},
 		"required": []string{"prompt"},
 	}
@@ -91,18 +95,29 @@ func (t *ReadImageTool) Execute(ctx context.Context, args map[string]any) *Resul
 		prompt = "Describe this image in detail."
 	}
 
+	imgPath, _ := args["path"].(string)
+	imgURL, _ := args["url"].(string)
+
+	if imgPath != "" && imgURL != "" {
+		return ErrorResult("Both 'path' and 'url' parameters cannot be specified. Choose only one.")
+	}
+
 	// If path is provided, load image from workspace file
 	images := MediaImagesFromCtx(ctx)
-	if imgPath, _ := args["path"].(string); imgPath != "" {
+	if imgPath != "" {
 		fileImages, err := t.loadImageFromPath(ctx, imgPath)
 		if err != nil {
 			return ErrorResult(err.Error())
 		}
 		images = fileImages
+	} else if imgURL != "" {
+		images = []providers.ImageContent{{
+			URL: imgURL,
+		}}
 	}
 
 	if len(images) == 0 {
-		return ErrorResult("No images available. Either send an image in the chat or provide a file path with the 'path' parameter.")
+		return ErrorResult("No images available. Either send an image in the chat, provide a file path with 'path', or provide an image URL with 'url'.")
 	}
 
 	chain := ResolveMediaProviderChain(ctx, "read_image", "", "",
@@ -138,6 +153,15 @@ func (t *ReadImageTool) callProvider(ctx context.Context, cp credentialProvider,
 	prompt := GetParamString(params, "prompt", "Describe this image in detail.")
 	images, _ := params["images"].([]providers.ImageContent)
 
+	// Anthropic Claude does not support URL references and requires base64-encoded image data.
+	if providerName == "anthropic" || providerName == "claude-cli" {
+		for _, img := range images {
+			if img.URL != "" && img.Data == "" {
+				return nil, nil, fmt.Errorf("provider %q does not support analyzing images directly from a URL", providerName)
+			}
+		}
+	}
+
 	// Get the full provider for Chat() access
 	p, err := t.registry.Get(ctx, providerName)
 	if err != nil {

internal/tools/read_image_test.go

@@ -0,0 +1,55 @@
+package tools
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"github.com/nextlevelbuilder/goclaw/internal/providers"
+)
+
+func TestReadImage_BothPathAndUrl_Error(t *testing.T) {
+	tool := NewReadImageTool(nil)
+
+	res := tool.Execute(context.Background(), map[string]any{
+		"prompt": "describe this",
+		"path":   "workspace/image.png",
+		"url":    "https://example.com/image.png",
+	})
+
+	if !res.IsError {
+		t.Fatalf("expected error when both path and url are provided")
+	}
+
+	if !strings.Contains(res.ForLLM, "Both 'path' and 'url' parameters cannot be specified") {
+		t.Errorf("unexpected error message: %s", res.ForLLM)
+	}
+}
+
+func TestReadImage_AnthropicURL_Error(t *testing.T) {
+	tool := NewReadImageTool(nil)
+
+	params := map[string]any{
+		"prompt": "describe this",
+		"images": []providers.ImageContent{
+			{
+				URL: "https://example.com/image.png",
+			},
+		},
+	}
+
+	_, _, err := tool.callProvider(context.Background(), nil, "anthropic", "claude-3-sonnet", params)
+	if err == nil {
+		t.Fatalf("expected error for anthropic provider with image URL")
+	}
+
+	if !strings.Contains(err.Error(), "does not support analyzing images directly from a URL") {
+		t.Errorf("unexpected error message: %v", err)
+	}
+
+	// Should also error for claude-cli
+	_, _, err = tool.callProvider(context.Background(), nil, "claude-cli", "claude-3-sonnet", params)
+	if err == nil {
+		t.Fatalf("expected error for claude-cli provider with image URL")
+	}
+}