feat: Ocean theme, guide tab, hide lambda from MCP API

- gr.themes.Ocean() + larger Model3D viewport
- Guide tab: usage steps, prompt tips, correct MCP setup (streamable HTTP
at /gradio_api/mcp/ — the old footer block showed the outdated /sse URL)
- show_api=False on the download-sync lambda so it no longer appears as an
MCP tool (sam3d_objects_mcp__lambda_)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

app.py

@@ -219,12 +219,10 @@ def reconstruct_objects(image: np.ndarray, prompt: str = "object", progress=gr.P
         return None, None, f"❌ Error:\n{tb[-1500:]}"
 
 
-with gr.Blocks(title="SAM 3D Objects MCP") as demo:
+with gr.Blocks(title="SAM 3D Objects MCP", theme=gr.themes.Ocean()) as demo:
     gr.Markdown("""
-    # 📦 SAM 3D Objects MCP Server
-    **Image (+ text prompt) → 3D Object (GLB)**
-
-    SAM3 segments the object you describe, SAM 3D Objects reconstructs it in 3D.
+    # 📦 SAM 3D Objects
+    **Image (+ text prompt) → 3D Object (GLB)** · powered by Meta's SAM3 + SAM 3D Objects · usable as MCP server
     """)
 
     with gr.Tab("Reconstruct"):
@@ -239,31 +237,66 @@ with gr.Blocks(title="SAM 3D Objects MCP") as demo:
                 preview = gr.Image(label="Segmented Object", type="numpy", interactive=False)
                 status = gr.Textbox(label="Status")
         with gr.Row():
-            output_model = gr.Model3D(label="3D Preview")
-            output_file = gr.File(label="Download")
+            output_model = gr.Model3D(label="3D Preview", height=420)
+            with gr.Column():
+                output_file = gr.File(label="Download")
         btn.click(reconstruct_objects, inputs=[input_image, input_prompt],
                   outputs=[output_model, preview, status])
-        output_model.change(lambda x: x, inputs=[output_model], outputs=[output_file])
+        output_model.change(lambda x: x, inputs=[output_model], outputs=[output_file],
+                            show_api=False)
+
+    with gr.Tab("Guide"):
+        gr.Markdown("""
+        ## How it works
+
+        1. **Upload an image** — photos and renders both work; one clearly visible object gives the best result.
+        2. **Describe what to reconstruct** — a short noun phrase like `robot`, `the red chair`, `laptop`.
+           The default `object` picks the most prominent thing in the image.
+        3. **Segment & Reconstruct** — SAM3 finds the best-matching instance (green preview),
+           SAM 3D Objects rebuilds it as a vertex-colored GLB mesh you can preview and download.
+
+        The first request after a restart loads both models and takes ~2 minutes extra; after that
+        a reconstruction takes roughly 1–2 minutes.
+
+        ### Prompt tips
+        - Short English noun phrases work best: `sofa`, `yellow school bus`, `coffee mug`
+        - If several matching objects exist, the highest-confidence one is used
+        - Getting the wrong object? Make the prompt more specific (`the left chair` won't help —
+          SAM3 matches concepts, not positions — but `wooden chair` will)
+
+        ## Use as MCP server
+
+        Add to your MCP client (Claude Code, Claude Desktop, Cursor, ...):
+
+        ```json
+        {
+          "mcpServers": {
+            "sam3d-objects": {
+              "url": "https://dev-bjoern-sam3d-objects-mcp.hf.space/gradio_api/mcp/"
+            }
+          }
+        }
+        ```
+
+        Or with the Claude Code CLI:
+
+        ```bash
+        claude mcp add --transport http sam3d-objects https://dev-bjoern-sam3d-objects-mcp.hf.space/gradio_api/mcp/
+        ```
+
+        For stdio-only clients (e.g. Claude Desktop) use
+        `npx mcp-remote https://dev-bjoern-sam3d-objects-mcp.hf.space/gradio_api/mcp/ --transport streamable-http`.
+
+        The `reconstruct_objects` tool takes an image (URL or uploaded file) and a text
+        prompt and returns the GLB, the segmentation preview and a status line.
+        Full API details: the **"Use via API or MCP"** link in the page footer.
+        """)
 
     with gr.Tab("Diagnose"):
         diag_btn = gr.Button("Diagnose GPU & Models")
         diag_out = gr.Textbox(lines=8, label="Diagnostics")
         diag_btn.click(diagnose, outputs=[diag_out])
 
-    gr.Markdown("""
-    ---
-    ### MCP Server
-    ```json
-    {
-      "mcpServers": {
-        "sam3d-objects": {
-          "url": "https://dev-bjoern-sam3d-objects-mcp.hf.space/gradio_api/mcp/sse"
-        }
-      }
-    }
-    ```
-    """)
-
 
 if __name__ == "__main__":
     demo.launch(mcp_server=True)