fix(chat): close a trailing @file mention so the Enter sends the message

CHANGELOG.md

@@ -32,6 +32,10 @@ between releases do not reach them. Remote-PC runtime bundles are versioned sepa
 - The command palette opens on an empty search every time. It no longer shows the previous
   search's results for a moment, during which a quick Tab could highlight a different row than the
   one it focused. ([#631](https://github.com/devswha/herdr-web-ui/pull/631))
+- A chat message that ends with an attached file's `@` mention is sent again. Pasted last, the
+  mention left the agent's file suggestions open, and the Enter took a suggestion instead of
+  sending, so the message stayed in the terminal's input box.
+  ([#635](https://github.com/devswha/herdr-web-ui/pull/635))
 
 ## [0.4.2] - 2026-10-09
 

server/index.ts

@@ -443,6 +443,19 @@ export function createServer(
    * the bytes, so the pane sees the whole gap. So does a Codex "blocked" only by questions
    * waiting collapsed in its queue: its main prompt still takes the message.
    */
+  /**
+   * A message whose last word is an `@file` mention leaves the agent's file suggestions open over
+   * it, and the Enter after the paste takes the suggestion instead of sending: the message stays in
+   * the input box (Claude Code 2.1.295, #404). A space after the mention closes them first; a
+   * payload already in bracketed-paste markers gets it inside them.
+   */
+  const closeMention = (text: string): string => {
+    const open = text.startsWith("\u001b[200~") ? "\u001b[200~" : "";
+    const close = open && text.endsWith("\u001b[201~") ? "\u001b[201~" : "";
+    const body = text.slice(open.length, text.length - close.length);
+    return /(?:^|\s)@\S+$/.test(body) ? `${open}${body} ${close}` : text;
+  };
+
   async function submitText(paneId: string, text: string, payload: string, arrivedAt: number, fromTerminal = false, authorize: () => void = () => {}): Promise<void> {
     const inTime = (): void => {
       authorize();
@@ -457,7 +470,7 @@ export function createServer(
     // the terminal's input line stands in for the keyboard: it types what the user wrote, an
     // answer into an open menu included, where agent.prompt would refuse
     if (!fromTerminal) try {
-      await agentPrompt(paneId, text);
+      await agentPrompt(paneId, closeMention(text));
       noteSubmitted(paneId, text);
       return;
     } catch (error) {
@@ -469,7 +482,7 @@ export function createServer(
     // a mirrored pane's browser never learned the program's paste mode, so `payload` came as bare
     // lines: several of them are shaped here as the same block typed into the mirror is. herdr is
     // asked only for such a block, so a one-line message never waits on it.
-    const shaped = await mirrorInput(payload, async () => await terminalAttach() ? null : (await paneContext(paneId)).agent);
+    const shaped = await mirrorInput(closeMention(payload), async () => await terminalAttach() ? null : (await paneContext(paneId)).agent);
     inTime();
     await paneSendText(paneId, shaped);
     await Bun.sleep(options.submitDelayMs ?? SUBMIT_DELAY_MS);
@@ -611,7 +624,7 @@ export function createServer(
       // Pending input is a guarded literal paste + Enter, never Codex's native Tab queue.
       // Keep the final key here so a disconnect, pane switch or new menu can cancel it.
       wrote = true;
-      await paneSendText(paneId, `\u001b[200~${text}\u001b[201~`);
+      await paneSendText(paneId, `\u001b[200~${closeMention(text)}\u001b[201~`);
       await Bun.sleep(options.submitDelayMs ?? SUBMIT_DELAY_MS);
       const beforeEnter = await pendingContext(owner, paneId, lease, identity, true);
       if (automatic && beforeEnter.working) throw new HerdrError("pending_wait", "The agent started another turn before this queued message could be committed");

server/pending-input.contract.test.ts

@@ -109,6 +109,13 @@ describe("connection-owned pending input", () => {
     expect(f.bytes()).toBe(`${paste(first.text)}\r${paste("second")}\r`);
   }, 30_000);
 
+  it("closes a trailing @file mention with a space before its Enter", async () => {
+    const f = await setup("mention");
+    const message = await f.queue(1, "look at @/tmp/shot.png");
+    await f.state("idle"); await f.removed(message.id); await f.waitBytes("\r");
+    expect(f.bytes()).toBe(`${paste("look at @/tmp/shot.png ")}\r`);
+  }, 30_000);
+
   it("promotes a pending message only once and does not send it again after completion", async () => {
     const f = await setup("promote"); const message = await f.queue(1, "steer once");
     f.socket.send({ type: "pending-action", id: 10, pane_id: f.pane, pending_id: message.id, action: "steer" });

server/submit.contract.test.ts

@@ -170,6 +170,20 @@ describe("WebSocket submit", () => {
     }
   }, 30_000);
 
+  it("closes a trailing @file mention inside the paste markers of a payload typed without agent.prompt", async () => {
+    const socket = await Socket.connect();
+    try {
+      const from = chunks(shell).length;
+      socket.send({ type: "submit", id: 21, pane_id: shell.pane, text: "look at @/tmp/shot.png", payload: paste("look at @/tmp/shot.png") });
+      expect(await socket.result(21)).toMatchObject({ ok: true });
+      const read = await received(shell, from, 1);
+      const enter = read.findIndex((chunk) => chunk.data.includes("\r"));
+      expect(read.slice(0, enter).map((chunk) => chunk.data).join("")).toBe(paste("look at @/tmp/shot.png "));
+    } finally {
+      socket.close();
+    }
+  }, 30_000);
+
   it("hands an agent the message through herdr's agent.prompt: the paste, then Enter apart", async () => {
     const socket = await Socket.connect();
     try {
@@ -186,6 +200,20 @@ describe("WebSocket submit", () => {
     }
   }, 30_000);
 
+  it("closes a trailing @file mention with a space, so the Enter sends rather than takes a file suggestion", async () => {
+    const socket = await Socket.connect();
+    try {
+      const from = chunks(agent).length;
+      socket.send({ type: "submit", id: 20, pane_id: agent.pane, text: "what is in @/tmp/shot.png", payload: "unused" });
+      expect(await socket.result(20)).toMatchObject({ ok: true });
+      const read = await received(agent, from, 1);
+      const enter = read.findIndex((chunk) => chunk.data.includes("\r"));
+      expect(read.slice(0, enter).map((chunk) => chunk.data).join("")).toBe(paste("what is in @/tmp/shot.png "));
+    } finally {
+      socket.close();
+    }
+  }, 30_000);
+
   it("refuses a message while the agent waits for an answer, typing nothing", async () => {
     const socket = await Socket.connect();
     await herdrRpc("pane.report_agent", { pane_id: agent.pane, source: "manual", agent: "claude", state: "blocked" });