fix(ai): prime echo suppression before agent input to stop OpenWrt ash variable leak

electron/bridges/ai/ptyExec.cjs

@@ -64,6 +64,7 @@ function startPtyJob(ptyStream, command, options) {
     expectedPrompt,
     typedInput = false,
     echoCommand,
+    onEchoSuppressionPrime,
     maxBufferedChars = 0,
     normalizeFinalOutput = true,
     enforceWallTimeout = false,
@@ -812,6 +813,21 @@ function startPtyJob(ptyStream, command, options) {
     writeInput(`${buildPendingInputClearPrefix(resolvedShellKind)}${wrapped}`);
   }
 
+  // Prime the renderer's display suppression before the first byte is typed
+  // (issue #3384). Shells whose line editor echoes input, such as BusyBox ash
+  // on OpenWrt, break long echoed lines at the terminal width with CR/LF; the
+  // wrapped fragments no longer contain the marker and would leak through the
+  // per-line echo filter as visible "variables" until the wrapper's own
+  // _I printf runs. Delivering the _I line over the data channel up front
+  // suppresses the whole echo; the _S output releases it, and finish() sends
+  // the _R reset (onProbeAborted) when the command never starts.
+  if (typeof onEchoSuppressionPrime === "function") {
+    try {
+      onEchoSuppressionPrime(marker);
+    } catch {
+      // Display suppression must never prevent the command from starting.
+    }
+  }
   if (probingShell) {
     writeInput(`${buildPendingInputClearPrefix(resolvedShellKind)}${buildLiveShellProbe(marker)}`);
   } else {

electron/bridges/ai/ptyExec.test.cjs

@@ -1420,3 +1420,44 @@ test("startPtyJob types the wrapper one code point per write for strict bastions
   assert.equal(result.ok, false);
   assert.equal(result.error, "Cancelled");
 });
+
+test("echo suppression prime is delivered before the first typed input (#3384)", async () => {
+  for (const probeLiveShell of [false, true]) {
+    const pty = new EventEmitter();
+    const events = [];
+    pty.write = (data) => {
+      if (data === "\x03") return;
+      events.push(`write:${data}`);
+    };
+    const job = startPtyJob(pty, "echo prime-order", {
+      shellKind: "posix",
+      probeLiveShell,
+      timeoutMs: 1000,
+      onEchoSuppressionPrime: (marker) => events.push(`prime:${marker}`),
+    });
+    assert.equal(events[0], `prime:${job.marker}`, "prime precedes every typed byte");
+    assert.ok((events[1] || "").startsWith("write:"), "first write follows the prime");
+    assert.equal(events.filter((event) => event.startsWith("prime:")).length, 1);
+    if (probeLiveShell) {
+      pty.emit("data", `${job.marker}_P:sh\n${job.marker}_Q`);
+    }
+    pty.emit("data", `${job.marker}_S\ndone\n${job.marker}_E:0\n`);
+    const result = await job.resultPromise;
+    assert.equal(result.ok, true, JSON.stringify(result));
+  }
+});
+
+test("a throwing echo suppression prime callback still types the command (#3384)", () => {
+  const writes = [];
+  const pty = new EventEmitter();
+  pty.write = (data) => writes.push(String(data));
+  const job = startPtyJob(pty, "echo resilient", {
+    shellKind: "posix",
+    timeoutMs: 1000,
+    onEchoSuppressionPrime: () => {
+      throw new Error("Renderer closed");
+    },
+  });
+  assert.ok(writes.some((data) => data.includes("echo resilient")));
+  job.cancel();
+});

electron/bridges/aiBridge/cattyExecHandlers.cjs

@@ -2,6 +2,7 @@
 // Module-level require on purpose: code inside registerCattyExecHandlers
 // runs under `with (ctx)` where bare `require` resolves to ctx.require
 // (based in electron/bridges/). Requiring here keeps the path unambiguous.
+const { emitTerminalSessionData } = require("../emitTerminalSessionData.cjs");
 const { formatSyntheticEcho } = require("../ai/shellUtils.cjs");
 const { remoteDisallowsExecChannelProbe, ensureSessionShellKindForExec } = require("../ai/sessionShellKind.cjs");
 
@@ -180,7 +181,11 @@ function registerCattyExecHandlers(ctx) {
             bastionKeystrokes: remoteDisallowsExecChannelProbe(session.remoteSshVersion),
             onProbeAborted: (marker) => {
               const contents = electronModule?.webContents?.fromId?.(session.webContentsId);
-              safeSend(contents, "netcatty:data", { sessionId, data: `${marker}_R\n` });
+              emitTerminalSessionData(contents, sessionId, `${marker}_R\n`, { session });
+            },
+            onEchoSuppressionPrime: (marker) => {
+              const contents = electronModule?.webContents?.fromId?.(session.webContentsId);
+              emitTerminalSessionData(contents, sessionId, `${marker}_I\n`, { session });
             },
             chatSessionId,
             expectedPrompt: getFreshIdlePrompt(session),

electron/bridges/aiEchoSuppressionOrdering.test.cjs

@@ -0,0 +1,65 @@
+const assert = require('node:assert/strict');
+const { EventEmitter } = require('node:events');
+const test = require('node:test');
+const { configureTerminalSessionDataEmitter, emitTerminalSessionData } = require('./emitTerminalSessionData.cjs');
+const { registerCattyExecHandlers } = require('./aiBridge/cattyExecHandlers.cjs');
+const { execViaPty } = require('./ai/ptyExec.cjs');
+const bridge = require('./mcpServerBridge.cjs');
+
+for (const surface of ['catty', 'mcp-exec', 'mcp-job']) {
+  for (const hasPort of [true, false]) {
+    test(`${surface} primes and resets on the PTY output transport (port=${hasPort})`, async (t) => {
+      const deliveries = [];
+      const pty = new EventEmitter();
+      const session = { protocol: 'local', shellKind: 'posix', pty, webContentsId: 7 };
+      const contents = { isDestroyed: () => false, send: (_channel, payload) => {
+        if (!payload.syntheticEcho) deliveries.push(['ipc', payload.data]);
+      } };
+      const sessions = new Map([['session', session]]);
+      configureTerminalSessionDataEmitter({ getSession: id => sessions.get(id), outputChannel: {
+        send: (_id, data) => {
+          if (!hasPort) return false;
+          deliveries.push(['port', data]);
+          return true;
+        },
+      } });
+      t.after(() => { bridge.cleanup(); configureTerminalSessionDataEmitter(); });
+      const transport = hasPort ? 'port' : 'ipc';
+      let writes = 0;
+      pty.write = data => {
+        if (data === '\x03') return;
+        if (writes++ === 0) {
+          assert.equal(deliveries.length, 1, 'prime arrives before any typed bytes');
+          assert.equal(deliveries[0][0], transport);
+          assert.match(deliveries[0][1], /__NCMCP_.*_I\r?\n$/);
+          emitTerminalSessionData(contents, 'session', 'wrapped echo\r\n', { session });
+        }
+      };
+      const electronModule = { webContents: { fromId: () => contents } };
+      bridge.init({ sessions, electronModule });
+      bridge.setPermissionMode('auto');
+      bridge.updateSessionMetadata([{ sessionId: 'session', protocol: 'local', connected: true }], 'chat');
+      let pending;
+      if (surface === 'catty') {
+        const handlers = new Map();
+        registerCattyExecHandlers({ ipcMain: { handle: (key, fn) => handlers.set(key, fn) },
+          validateSender: () => true, sessions, mcpServerBridge: bridge, electronModule,
+          safeSend: (target, ...args) => target.send(...args), execViaPty, getFreshIdlePrompt: () => '' });
+        pending = handlers.get('netcatty:ai:exec')({ sender: contents }, { sessionId: 'session', command: 'echo test', chatSessionId: 'chat' });
+      } else {
+        pending = bridge.dispatchBuiltinRpc(surface === 'mcp-job' ? 'netcatty/jobStart' : 'netcatty/exec', {
+          sessionId: 'session', command: 'echo test', chatSessionId: 'chat',
+        });
+      }
+      await new Promise(resolve => setTimeout(resolve, 30));
+      assert.ok(writes > 0, 'execution must reach the PTY');
+      bridge.cancelAllPtyExecs();
+      pty.emit("close");
+      await pending;
+      assert.equal(deliveries[1][0], transport);
+      assert.equal(deliveries[1][1], 'wrapped echo\r\n');
+      assert.equal(deliveries.at(-1)[0], transport);
+      assert.match(deliveries.at(-1)[1], /__NCMCP_.*_R\r?\n$/);
+    });
+  }
+}

electron/bridges/mcpServerBridge.cjs

@@ -21,6 +21,7 @@ const {
 } = require("./ai/commandSafety.cjs");
 const { execViaPty, startPtyJob, execViaChannel, execViaRawPty } = require("./ai/ptyExec.cjs");
 const { safeSend } = require("./ipcUtils.cjs");
+const { emitTerminalSessionData } = require("./emitTerminalSessionData.cjs");
 const { getCliDiscoveryFilePath } = require("../cli/discoveryPath.cjs");
 const { EXTERNAL_MCP_CHAT_SESSION_ID } = require("../cli/externalMcpDiscoveryPath.cjs");
 const sftpBridge = require("./sftpBridge.cjs");
@@ -487,6 +488,10 @@ function shutdownHost({ preserveScopedMetadata = false } = {}) {
 function echoCommandToSession(session, sessionId, command, { syntheticEcho = true } = {}) {
   if (!electronModule || !session?.webContentsId || !command) return;
   const contents = electronModule.webContents?.fromId?.(session.webContentsId);
+  if (!syntheticEcho) {
+    emitTerminalSessionData(contents, sessionId, formatSyntheticEcho(command), { session });
+    return;
+  }
   safeSend(contents, "netcatty:data", {
     sessionId,
     data: formatSyntheticEcho(command),

electron/bridges/mcpServerBridge/execHandlers.cjs

@@ -149,6 +149,7 @@ function createExecHandlerApi(ctx) {
             probeLiveShell: true,
             bastionKeystrokes: remoteDisallowsExecChannelProbe(session.remoteSshVersion),
             onProbeAborted: (marker) => echoCommandToSession(session, sessionId, `${marker}_R`, { syntheticEcho: false }),
+            onEchoSuppressionPrime: (marker) => echoCommandToSession(session, sessionId, `${marker}_I`, { syntheticEcho: false }),
             expectedPrompt: getFreshIdlePrompt(session),
             typedInput: true,
             echoCommand: (rawCommand) => echoCommandToSession(session, sessionId, rawCommand),
@@ -319,6 +320,7 @@ function createExecHandlerApi(ctx) {
             probeLiveShell: true,
             bastionKeystrokes: remoteDisallowsExecChannelProbe(session.remoteSshVersion),
             onProbeAborted: (marker) => echoCommandToSession(session, sessionId, `${marker}_R`, { syntheticEcho: false }),
+            onEchoSuppressionPrime: (marker) => echoCommandToSession(session, sessionId, `${marker}_I`, { syntheticEcho: false }),
             chatSessionId,
             expectedPrompt: getFreshIdlePrompt(session),
             typedInput: true,

electron/preloadDataBacklog.test.cjs

@@ -1802,6 +1802,34 @@ test("OpenWrt bounded wrapper continuations stay hidden across fragmented echoes
   }
 });
 
+test("primed suppression hides BusyBox ash echo wrapped mid-marker (#3384)", () => {
+  const preload = loadPreloadWithFakeElectron();
+  try {
+    const received = [];
+    const sessionId = 'ash-wrap';
+    const marker = '__NCMCP_mttikd5b_ccbc892e865a115a80c88afdc77b96a6__';
+    preload.api.onSessionData(sessionId, chunk => received.push(chunk));
+    // The exec bridge primes display suppression over the data channel before
+    // the wrapper is typed, mirroring onEchoSuppressionPrime in ptyExec.cjs.
+    preload.handlers.get('netcatty:data')({}, { sessionId, data: `${marker}_I\n` });
+    // BusyBox ash's line editor breaks the echoed first wrapper line at the
+    // terminal width, so the second PTY line carries no complete __NCMCP_
+    // marker and the per-line echo filter alone cannot drop it.
+    const firstLine = ` ${marker}=0; printf '\\n%s\\n' '${marker}_I'`;
+    const secondLine = ` : '${marker}'; ${marker}_cmd='echo visible-output'; \\`;
+    const echo = `${firstLine.slice(0, 55)}\r\n${firstLine.slice(55)}\r\n`
+      + `${secondLine.slice(0, 70)}\r\n${secondLine.slice(70)}\r\n`
+      + `> : '${marker}'; printf '%s\\n' '${marker}_S'\r\n`;
+    const data = `${echo}\n${marker}_S\r\nvisible-output\r\n${marker}_E:0\r\n`;
+    for (let offset = 0; offset < data.length; offset += 7) {
+      preload.handlers.get('netcatty:data')({}, { sessionId, data: data.slice(offset, offset + 7) });
+    }
+    assert.equal(received.join(''), 'visible-output\r\n');
+  } finally {
+    preload.cleanup();
+  }
+});
+
 
 test("ordinary text resembling an OpenWrt continuation is released", async () => {
   const preload = loadPreloadWithFakeElectron();
@@ -1873,3 +1901,61 @@ test("aborted input releases custom prompts and ignores a late input marker", ()
     assert.equal(received.join(""), "normal output\nlate prompt\n");
   } finally { preload.cleanup(); }
 });
+
+test('real OpenWrt ash hides wrapped input and preserves output with priming (#3384)', {
+  skip: !process.env.NETCATTY_OPENWRT_SSH_PORT,
+  timeout: 60000,
+}, async () => {
+  const { Client } = require('ssh2');
+  const { execViaPty } = require('./bridges/ai/ptyExec.cjs');
+  const client = new Client();
+  await new Promise((resolve, reject) => client.once('ready', resolve).once('error', reject).connect({
+    host: '127.0.0.1', port: Number(process.env.NETCATTY_OPENWRT_SSH_PORT), username: 'root', password: '',
+  }));
+  try {
+    for (const cols of [80, 120]) {
+      for (const probeLiveShell of [false, true]) {
+        const preload = loadPreloadWithFakeElectron();
+        const stream = await new Promise((resolve, reject) => client.shell({ term: 'xterm', cols, rows: 30 },
+          (error, value) => error ? reject(error) : resolve(value)));
+        try {
+          await new Promise((resolve, reject) => {
+            let output = '';
+            const timer = setTimeout(() => reject(new Error('OpenWrt prompt missing')), 5000);
+            const onData = data => {
+              output += data;
+              if (output.includes(':~# ')) {
+                clearTimeout(timer);
+                stream.removeListener('data', onData);
+                resolve();
+              }
+            };
+            stream.on('data', onData);
+          });
+          const received = [];
+          const sessionId = `openwrt-${cols}-${probeLiveShell}`;
+          preload.api.onSessionData(sessionId, chunk => received.push(chunk));
+          const deliver = data => preload.handlers.get('netcatty:data')({}, { sessionId, data: String(data) });
+          stream.on('data', deliver);
+          const result = await execViaPty(stream, "printf 'visible-output\\n'", {
+            shellKind: 'posix', probeLiveShell, typedInput: true, timeoutMs: 5000,
+            onEchoSuppressionPrime: marker => deliver(`${marker}_I\n`),
+            onProbeAborted: marker => deliver(`${marker}_R\n`),
+          });
+          await sleep(150);
+          assert.equal(result.ok, true, JSON.stringify(result));
+          assert.equal(result.stdout.trim(), 'visible-output');
+          const display = received.join('');
+          assert.match(display, /visible-output/);
+          assert.doesNotMatch(display, /__nc_|__NCMCP_|printf|eval|unset|_cmd=|_d=/,
+            JSON.stringify({ cols, probeLiveShell, display }));
+        } finally {
+          stream.close();
+          preload.cleanup();
+        }
+      }
+    }
+  } finally {
+    client.end();
+  }
+});

electron/terminalWorker/aiExec.cjs

@@ -298,6 +298,12 @@ function createWorkerAiExecHandler({
             data: `${marker}_R\n`,
           });
         },
+        onEchoSuppressionPrime: (marker) => {
+          event?.sender?.send?.("netcatty:data", {
+            sessionId,
+            data: `${marker}_I\n`,
+          });
+        },
         chatSessionId,
         expectedPrompt: getFreshIdlePrompt(session),
         typedInput: true,
@@ -502,6 +508,12 @@ function createWorkerAiJobStartHandler({
             data: `${marker}_R\n`,
           });
         },
+        onEchoSuppressionPrime: (marker) => {
+          event?.sender?.send?.("netcatty:data", {
+            sessionId,
+            data: `${marker}_I\n`,
+          });
+        },
         chatSessionId,
         expectedPrompt: getFreshIdlePrompt(session),
         typedInput: true,

electron/terminalWorker/aiExec.test.cjs

@@ -145,6 +145,7 @@ test("worker AI background jobs start, poll, stop, and block overlapping exec",
   assert.equal(started.command, "npm test");
   assert.equal(started.status, "running");
   assert.equal(started.outputMode, "foreground-mirrored");
+  const marker = await extractMarker(pty.writes);
   assert.deepEqual(event.rendererMessages, [
     {
       channel: "netcatty:data",
@@ -154,9 +155,14 @@ test("worker AI background jobs start, poll, stop, and block overlapping exec",
         syntheticEcho: true,
       },
     },
+    {
+      channel: "netcatty:data",
+      payload: {
+        sessionId: "ssh-1",
+        data: `${marker}_I\n`,
+      },
+    },
   ]);
-
-  const marker = await extractMarker(pty.writes);
   pty.emit("data", `${marker}_S\r\nready\r\n`);
   await nextTick();