Fix MCP server 405 error - separate MCP from local lineage extraction

- Remove automatic MCP server fallback from extraction functions
- MCP servers are now only used via explicit Test Connection
- Local lineage extraction works independently without MCP
- Fixes "Method Not Allowed" error when extracting sample data

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app.py

@@ -539,18 +539,10 @@ def load_sample(sample_type: str) -> str:
 def extract_lineage_from_text(
     metadata_text: str,
     source_type: str,
-    visualization_format: str,
-    mcp_server: str = "",
-    mcp_api_key: str = ""
+    visualization_format: str
 ) -> Tuple[str, str]:
-    """Extract lineage from provided metadata text."""
-    # Try MCP server first if configured
-    if mcp_server:
-        viz, summary = send_to_mcp(mcp_server, mcp_api_key, metadata_text, source_type, visualization_format)
-        if viz or (summary and not summary.startswith("Error")):
-            return viz, summary
-
-    # Local processing
+    """Extract lineage from provided metadata text (local processing only)."""
+    # Local processing - MCP servers are used separately via explicit fetch
     if not metadata_text.strip():
         return "", "Please provide metadata content."
 
@@ -568,16 +560,9 @@ def extract_lineage_from_bigquery(
     project_id: str,
     query: str,
     api_key: str,
-    visualization_format: str,
-    mcp_server: str = "",
-    mcp_api_key: str = ""
+    visualization_format: str
 ) -> Tuple[str, str]:
-    """Extract lineage from BigQuery."""
-    if mcp_server:
-        viz, summary = send_to_mcp(mcp_server, mcp_api_key, query, "BigQuery", visualization_format)
-        if viz or (summary and not summary.startswith("Error")):
-            return viz, summary
-
+    """Extract lineage from BigQuery (local processing)."""
     # Local stub - would integrate with BigQuery API in production
     viz = f"""graph TD
     subgraph BigQuery Project: {project_id or 'your-project'}
@@ -592,23 +577,16 @@ def extract_lineage_from_bigquery(
 
 def extract_lineage_from_url(
     url: str,
-    visualization_format: str,
-    mcp_server: str = "",
-    mcp_api_key: str = ""
+    visualization_format: str
 ) -> Tuple[str, str]:
-    """Extract lineage from URL/API endpoint."""
-    if mcp_server:
-        viz, summary = send_to_mcp(mcp_server, mcp_api_key, url, "URL", visualization_format)
-        if viz or (summary and not summary.startswith("Error")):
-            return viz, summary
-
+    """Extract lineage from URL/API endpoint (local processing)."""
     # Try to fetch the URL
     if url:
         try:
             resp = requests.get(url, timeout=10)
             if resp.status_code == 200:
                 return extract_lineage_from_text(resp.text, "API Response", visualization_format)
-        except Exception as e:
+        except Exception:
             pass
 
     viz = "graph TD\n    A[API Source] --> B[Data Pipeline] --> C[Output]"
@@ -748,7 +726,7 @@ with gr.Blocks(
 
             extract_btn.click(
                 fn=extract_lineage_from_text,
-                inputs=[metadata_input, source_type, viz_format, mcp_server, mcp_api_key],
+                inputs=[metadata_input, source_type, viz_format],
                 outputs=[output_viz, output_summary]
             )
 
@@ -794,7 +772,7 @@ with gr.Blocks(
 
             bq_extract_btn.click(
                 fn=extract_lineage_from_bigquery,
-                inputs=[bq_project, bq_query, bq_creds, bq_viz_format, mcp_server, mcp_api_key],
+                inputs=[bq_project, bq_query, bq_creds, bq_viz_format],
                 outputs=[bq_output_viz, bq_output_summary]
             )
 
@@ -825,7 +803,7 @@ with gr.Blocks(
 
             url_extract_btn.click(
                 fn=extract_lineage_from_url,
-                inputs=[url_input, url_viz_format, mcp_server, mcp_api_key],
+                inputs=[url_input, url_viz_format],
                 outputs=[url_output_viz, url_output_summary]
             )