From f29e15c05d79d7459821c72fdb5abaf3ee5fe89b Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Sat, 25 Apr 2026 03:17:31 +0100
Subject: [PATCH] fix(telegram): bound tool progress preview formatting

Co-authored-by: Neerav Makwana <261249544+neeravmakwana@users.noreply.github.com>
---
 .../telegram/src/bot-message-dispatch.test.ts | 24 +++++++++++++++++++
 .../telegram/src/bot-message-dispatch.ts      | 17 ++++++++++---
 2 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/extensions/telegram/src/bot-message-dispatch.test.ts b/extensions/telegram/src/bot-message-dispatch.test.ts
index ee1697acf4d..ed9ce3563c3 100644
--- a/extensions/telegram/src/bot-message-dispatch.test.ts
+++ b/extensions/telegram/src/bot-message-dispatch.test.ts
@@ -547,6 +547,30 @@ describe("dispatchTelegramMessage draft streaming", () => {
     );
   });
 
+  it("bounds Telegram tool progress markdown preview formatting", async () => {
+    const draftStream = createDraftStream();
+    createTelegramDraftStream.mockReturnValue(draftStream);
+    const longProgress = `${"`".repeat(1000)}${"x".repeat(1000)}[label](tg://user?id=123)`;
+    dispatchReplyWithBufferedBlockDispatcher.mockImplementation(async ({ replyOptions }) => {
+      await replyOptions?.onItemEvent?.({ progressText: longProgress });
+      return { queuedFinal: false };
+    });
+
+    await dispatchWithContext({
+      context: createContext(),
+      streamMode: "partial",
+      telegramCfg: { streaming: { preview: { toolProgress: true } } },
+    });
+
+    const lastPreviewText = draftStream.update.mock.calls.at(-1)?.[0] ?? "";
+    const progressLine = lastPreviewText.split("\n").at(1) ?? "";
+
+    expect(lastPreviewText.length).toBeLessThan(340);
+    expect(progressLine).toMatch(/^• `{10}/);
+    expect(progressLine).toContain("…");
+    expect(renderTelegramHtmlText(lastPreviewText)).not.toContain("<a ");
+  });
+
   it("keeps block streaming enabled when account config enables it", async () => {
     dispatchReplyWithBufferedBlockDispatcher.mockImplementation(async ({ dispatcherOptions }) => {
       await dispatcherOptions.deliver({ text: "Hello" }, { kind: "final" });
diff --git a/extensions/telegram/src/bot-message-dispatch.ts b/extensions/telegram/src/bot-message-dispatch.ts
index c6249fee333..90fb2800afc 100644
--- a/extensions/telegram/src/bot-message-dispatch.ts
+++ b/extensions/telegram/src/bot-message-dispatch.ts
@@ -207,13 +207,24 @@ function resolveTelegramReasoningLevel(params: {
   return "off";
 }
 
+const MAX_PROGRESS_MARKDOWN_TEXT_CHARS = 300;
+const MAX_PROGRESS_MARKDOWN_FENCE_CHARS = 10;
+
+function clipProgressMarkdownText(text: string): string {
+  if (text.length <= MAX_PROGRESS_MARKDOWN_TEXT_CHARS) {
+    return text;
+  }
+  return `${text.slice(0, MAX_PROGRESS_MARKDOWN_TEXT_CHARS - 1).trimEnd()}…`;
+}
+
 function formatProgressAsMarkdownCode(text: string): string {
+  const clipped = clipProgressMarkdownText(text);
   const maxBacktickRun = Math.max(
     0,
-    ...Array.from(text.matchAll(/`+/g), (match) => match[0].length),
+    ...Array.from(clipped.matchAll(/`+/g), (match) => match[0].length),
   );
-  const fence = "`".repeat(maxBacktickRun + 1);
-  return `${fence}${text}${fence}`;
+  const fence = "`".repeat(Math.min(maxBacktickRun + 1, MAX_PROGRESS_MARKDOWN_FENCE_CHARS));
+  return `${fence}${clipped}${fence}`;
 }
 
 export const dispatchTelegramMessage = async ({