diff --git a/packages/app/src/terminal/runtime/terminal-emulator-runtime.ts b/packages/app/src/terminal/runtime/terminal-emulator-runtime.ts
index f25c420c5..bf766c052 100644
--- a/packages/app/src/terminal/runtime/terminal-emulator-runtime.ts
+++ b/packages/app/src/terminal/runtime/terminal-emulator-runtime.ts
@@ -211,6 +211,12 @@ export class TerminalEmulatorRuntime {
 
     terminal.loadAddon(new ImageAddon());
 
+    // Suppress terminal query responses — the server-side headless xterm handles these.
+    // Without this, xterm.js generates DA/CPR responses via onData that feed back
+    // to the PTY as visible text.
+    terminal.parser.registerCsiHandler({ final: "c" }, () => true);
+    terminal.parser.registerCsiHandler({ final: "R" }, () => true);
+
     const restoreDocumentStyles = this.applyDocumentBoundsStyles({
       root: input.root,
     });
diff --git a/packages/server/src/terminal/terminal.ts b/packages/server/src/terminal/terminal.ts
index d10d34f6f..59acda802 100644
--- a/packages/server/src/terminal/terminal.ts
+++ b/packages/server/src/terminal/terminal.ts
@@ -272,6 +272,15 @@ export async function createTerminal(options: CreateTerminalOptions): Promise<Te
     },
   });
 
+  // Respond to DA1 queries (CSI c or CSI 0 c) — apps like nvim query terminal capabilities
+  terminal.parser.registerCsiHandler({ final: "c" }, (params) => {
+    if (params.length === 0 || (params.length === 1 && params[0] === 0)) {
+      ptyProcess.write("\x1b[?62;4;22c");
+      return true;
+    }
+    return false;
+  });
+
   function emitExit(): void {
     if (exitEmitted) {
       return;