fix: resolve MCP tool name validation error

app.py

@@ -135,12 +135,109 @@ def scan_code(code: str, severity_threshold: str = "MEDIUM") -> str:
     return format_results_markdown(results)
 
 
-def load_sample(sample_name: str) -> str:
-    """Load sample vulnerable code."""
-    return SAMPLE_CODES.get(sample_name, "")
+# Sample loader functions - use named functions instead of lambda
+def load_sample_sql_injection():
+    """Load SQL Injection sample code."""
+    return SAMPLE_CODES["SQL Injection"]
+
+
+def load_sample_hardcoded_secret():
+    """Load Hardcoded Secret sample code."""
+    return SAMPLE_CODES["Hardcoded Secret"]
+
+
+def load_sample_path_traversal():
+    """Load Path Traversal sample code."""
+    return SAMPLE_CODES["Path Traversal"]
+
+
+def load_sample_insecure_deserialization():
+    """Load Insecure Deserialization sample code."""
+    return SAMPLE_CODES["Insecure Deserialization"]
+
+
+# Mapping of sample names to loader functions
+SAMPLE_LOADERS = {
+    "SQL Injection": load_sample_sql_injection,
+    "Hardcoded Secret": load_sample_hardcoded_secret,
+    "Path Traversal": load_sample_path_traversal,
+    "Insecure Deserialization": load_sample_insecure_deserialization,
+}
+
+
+# Full UI with Blocks (not exposed to MCP)
+def create_blocks_ui():
+    """Create the Blocks UI - separated to avoid MCP exposure."""
+    with gr.Blocks(
+            title="🔒 Simple Security Scanner",
+            theme=gr.themes.Soft()
+    ) as blocks_demo:
+        gr.Markdown("""
+        # 🔒 Simple Security Scanner
+
+        **Scans Python code for security vulnerabilities and provides beginner-friendly explanations.**
+
+        Also available as an MCP (Model Context Protocol) server.
+        """)
+
+        with gr.Row():
+            with gr.Column(scale=2):
+                code_input = gr.Code(
+                    label="Python Code Input",
+                    language="python",
+                    lines=15,
+                )
+
+                with gr.Row():
+                    severity_dropdown = gr.Dropdown(
+                        choices=["LOW", "MEDIUM", "HIGH", "CRITICAL"],
+                        value="MEDIUM",
+                        label="Minimum Severity",
+                        scale=1
+                    )
+                    scan_btn = gr.Button("🔍 Scan", variant="primary", scale=2)
+
+            with gr.Column(scale=1):
+                gr.Markdown("### 📝 Sample Code")
+                for name, loader_fn in SAMPLE_LOADERS.items():
+                    sample_btn = gr.Button(name, size="sm")
+                    sample_btn.click(
+                        fn=loader_fn,
+                        outputs=code_input,
+                        api_name=False  # Do not expose to MCP
+                    )
+
+        output = gr.Markdown(label="Scan Results")
+
+        scan_btn.click(
+            fn=scan_code,
+            inputs=[code_input, severity_dropdown],
+            outputs=output,
+            api_name=False  # Do not expose to MCP
+        )
+
+        gr.Markdown("""
+        ---
+        ### 🛠️ Use as MCP Server
+
+        Connect with Claude Desktop or other MCP clients:
+```json
+        {
+          "mcpServers": {
+            "security-scanner": {
+              "command": "npx",
+              "args": ["mcp-remote", "https://mcp-1st-birthday-simple-security-scanner.hf.space/gradio_api/mcp/sse"]
+            }
+          }
+        }
+```
+        """)
+
+    return blocks_demo
 
 
 # MCP Tool - gr.Interface for MCP server exposure
+# Tool name must match pattern: ^[a-zA-Z0-9_-]{1,64}$
 mcp_interface = gr.Interface(
     fn=scan_code,
     inputs=[
@@ -151,75 +248,14 @@ mcp_interface = gr.Interface(
             label="severity_threshold"
         )
     ],
-    outputs=gr.Textbox(label="Scan Results"),
+    outputs=gr.Textbox(label="results"),
     title="Security Scanner",
     description="Scan Python code for security vulnerabilities and get beginner-friendly explanations.",
-    api_name="scan_security"
+    api_name="scan_code"  # MCP tool name: only alphanumeric, underscore, hyphen allowed
 )
 
-# Full UI with Blocks
-with gr.Blocks(
-        title="🔒 Simple Security Scanner",
-        theme=gr.themes.Soft()
-) as blocks_demo:
-    gr.Markdown("""
-    # 🔒 Simple Security Scanner
-
-    **Scans Python code for security vulnerabilities and provides beginner-friendly explanations.**
-
-    Also available as an MCP (Model Context Protocol) server.
-    """)
-
-    with gr.Row():
-        with gr.Column(scale=2):
-            code_input = gr.Code(
-                label="Python Code Input",
-                language="python",
-                lines=15,
-            )
-
-            with gr.Row():
-                severity_dropdown = gr.Dropdown(
-                    choices=["LOW", "MEDIUM", "HIGH", "CRITICAL"],
-                    value="MEDIUM",
-                    label="Minimum Severity",
-                    scale=1
-                )
-                scan_btn = gr.Button("🔍 Scan", variant="primary", scale=2)
-
-        with gr.Column(scale=1):
-            gr.Markdown("### 📝 Sample Code")
-            for name in SAMPLE_CODES.keys():
-                sample_btn = gr.Button(name, size="sm")
-                sample_btn.click(
-                    fn=lambda n=name: load_sample(n),
-                    outputs=code_input
-                )
-
-    output = gr.Markdown(label="Scan Results")
-
-    scan_btn.click(
-        fn=scan_code,
-        inputs=[code_input, severity_dropdown],
-        outputs=output
-    )
-
-    gr.Markdown("""
-    ---
-    ### 🛠️ Use as MCP Server
-
-    Connect with Claude Desktop or other MCP clients:
-```json
-    {
-      "mcpServers": {
-        "security-scanner": {
-          "command": "npx",
-          "args": ["mcp-remote", "https://mcp-1st-birthday-simple-security-scanner.hf.space/gradio_api/mcp/sse"]
-        }
-      }
-    }
-```
-    """)
+# Create UI
+blocks_demo = create_blocks_ui()
 
 # Combine: TabbedInterface for both UI and MCP
 demo = gr.TabbedInterface(