fix mcp server error responses

src/mcp-server.rs

@@ -100,18 +100,28 @@ fn dispatch_tool(name: &str, args: &Value) -> Result<String, String> {
 // ── Main loop ───────────────────────────────────────────────────
 
 fn main() {
+    eprintln!("consciousness-mcp: starting");
     let stdin = io::stdin();
     let reader = stdin.lock();
 
     for line in reader.lines() {
         let line = match line {
             Ok(l) if !l.is_empty() => l,
-            _ => continue,
+            Ok(_) => continue, // blank line
+            Err(e) => {
+                eprintln!("consciousness-mcp: stdin read error: {e}");
+                break;
+            }
         };
 
         let req: Request = match serde_json::from_str(&line) {
             Ok(r) => r,
-            Err(_) => continue,
+            Err(e) => {
+                eprintln!("consciousness-mcp: bad json-rpc: {e}");
+                eprintln!("consciousness-mcp: input was: {line}");
+                respond_error(Value::Null, -32700, &format!("parse error: {e}"));
+                continue;
+            }
         };
 
         match req.method.as_str() {
@@ -165,4 +175,5 @@ fn main() {
             }
         }
     }
+    eprintln!("consciousness-mcp: stdin closed, exiting");
 }