Fix misleading HTTP transport error message

- Remove reference to non-existent --legacy flag
- Clarify that HTTP transport is not implemented with official rmcp SDK
- Update README.md to remove HTTP transport example
- Add note explaining STDIO is the only supported transport
- Improve error message formatting and clarity

Author: jruokola

README.md

@@ -492,13 +492,12 @@ codegraph index -r /path/to/project
 # Start MCP server (for Claude Desktop, LM Studio, etc.)
 codegraph start stdio
 
-# Start streamable HTTP server (alternative)
-codegraph start http
-
 # List available MCP tools
 codegraph tools list
 ```
 
+**Note:** HTTP transport is not yet implemented with the official rmcp SDK. Use STDIO transport for all MCP integrations.
+
 ### Using with Claude Desktop
 
 Add to your Claude Desktop config (`~/Library/Application Support/Claude/claude_desktop_config.json` on Mac):

crates/codegraph-mcp/src/bin/codegraph.rs

@@ -832,14 +832,17 @@ async fn handle_start(
             key,
             cors: _,
         } => {
-            eprintln!("🚧 HTTP transport with official SDK not yet implemented");
-            eprintln!("💡 Use STDIO transport for 100% official SDK compliance:");
+            eprintln!("🚧 HTTP transport not yet implemented with official rmcp SDK");
+            eprintln!();
+            eprintln!("💡 Use STDIO transport instead (recommended):");
             eprintln!("   codegraph start stdio");
-            eprintln!("💡 Or use legacy HTTP server:");
-            eprintln!("   codegraph start http --legacy");
+            eprintln!();
+            eprintln!("📋 HTTP transport implementation is tracked in the roadmap.");
+            eprintln!("   The official rmcp SDK supports streamable HTTP, but integration");
+            eprintln!("   with CodeGraph's agentic tools is not yet complete.");
 
             return Err(anyhow::anyhow!(
-                "HTTP transport requires legacy mode or official SDK implementation"
+                "HTTP transport not yet implemented - use 'codegraph start stdio' instead"
             ));
         }
         TransportType::Dual {