fix(telegram): keep streamed tool-progress lines on separate lines

Telegram's rich-markdown renderer treats a lone "\n" as a soft break
(rendered as a space), so streamed tool-progress draft lines joined by a
single newline collapsed onto one line. Pass "\n\n" as the progress-draft
line separator for Telegram; it renders a blank line as a single break, so
each tool/thinking/commentary line gets its own line again. Other channels
keep the single-newline default, so Discord and the rest are unaffected.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

extensions/telegram/src/bot-message-dispatch.test.ts

@@ -2374,7 +2374,7 @@ describe("dispatchTelegramMessage draft streaming", () => {
     });
 
     expect(answerDraftStream.update).toHaveBeenCalledWith(
-      "Cracking\n\n`🛠️ Exec`\n`🛠️ git rev-parse --abbrev-ref HEAD`",
+      "Cracking\n\n`🛠️ Exec`\n\n`🛠️ git rev-parse --abbrev-ref HEAD`",
     );
     expect(answerDraftStream.update).not.toHaveBeenCalledWith("Branch is up to date");
     expect(answerDraftStream.forceNewMessage).toHaveBeenCalledTimes(1);
@@ -2434,7 +2434,7 @@ describe("dispatchTelegramMessage draft streaming", () => {
       expect.stringContaining("stdout line one"),
     );
     expect(answerDraftStream.update).toHaveBeenLastCalledWith(
-      "Shelling\n\n`🛠️ Exec`\n`🔎 Web Search: docs lookup`",
+      "Shelling\n\n`🛠️ Exec`\n\n`🔎 Web Search: docs lookup`",
     );
     expect(deliverReplies).not.toHaveBeenCalled();
   });
@@ -2670,7 +2670,7 @@ describe("dispatchTelegramMessage draft streaming", () => {
     });
 
     expect(createTelegramDraftStream).toHaveBeenCalledTimes(1);
-    expect(draftStream.update).toHaveBeenCalledWith("Shelling\n\n`🛠️ Exec`\n• _Checking files_");
+    expect(draftStream.update).toHaveBeenCalledWith("Shelling\n\n`🛠️ Exec`\n\n• _Checking files_");
   });
 
   it("renders configured Telegram commentary progress from preamble item events", async () => {
@@ -2840,7 +2840,7 @@ describe("dispatchTelegramMessage draft streaming", () => {
     });
 
     expect(draftStream.update).toHaveBeenCalledWith(
-      "Shelling\n\n`🔎 Web Search: docs lookup`\n• `tests passed`",
+      "Shelling\n\n`🔎 Web Search: docs lookup`\n\n• `tests passed`",
     );
     expect(draftStream.forceNewMessage).toHaveBeenCalledTimes(1);
     expect(draftStream.materialize).not.toHaveBeenCalled();

extensions/telegram/src/bot-message-dispatch.ts

@@ -967,6 +967,10 @@ export const dispatchTelegramMessage = async ({
     active: Boolean(answerLane.stream),
     seed: progressSeed,
     formatLine: formatTelegramProgressLine,
+    // Telegram's rich-markdown renderer collapses a lone "\n" to a space, so
+    // tool-progress lines need a blank line between them to stay on their own
+    // line (it renders "\n\n" as a single break, not a double).
+    lineSeparator: "\n\n",
     update: async (streamText, options) => {
       await prepareAnswerLaneForToolProgress();
       answerLane.lastPartialText = streamText;

src/channels/progress-draft-compositor.ts

@@ -39,6 +39,9 @@ export function createChannelProgressDraftCompositor(params: {
   deleteCurrent?: () => Promise<void> | void;
   tryNativeUpdate?: (text: string) => Promise<boolean> | boolean;
   formatLine?: (line: string) => string;
+  /** Separator between rendered draft lines; forwarded to the draft formatter.
+   *  Telegram passes "\n\n" because its renderer collapses a lone newline. */
+  lineSeparator?: string;
   isEmptyLine?: (line: ProgressDraftLine | undefined) => boolean;
   shouldStartNow?: (line: ProgressDraftLine | undefined) => boolean;
 }) {
@@ -66,6 +69,7 @@ export function createChannelProgressDraftCompositor(params: {
       lines: draftLines,
       seed: params.seed,
       formatLine: options?.formatted === false ? undefined : params.formatLine,
+      lineSeparator: params.lineSeparator,
     });
 
   const clearProgressState = (suppressed: boolean) => {

src/channels/streaming.ts

@@ -1047,6 +1047,11 @@ export function formatChannelProgressDraftText(params: {
   formatLine?: (line: string) => string;
   /** Prefix used for plain progress lines that lack their own icon. */
   bullet?: string;
+  /** Separator between rendered progress lines. Defaults to a single newline.
+   *  Telegram's rich-markdown parser treats a lone "\n" as a soft break (space),
+   *  so its draft passes "\n\n"; channels where a single newline already breaks
+   *  the line (Discord) keep the default. */
+  lineSeparator?: string;
 }): string {
   const rawLabel = resolveChannelProgressDraftLabel({
     entry: params.entry,
@@ -1058,6 +1063,7 @@ export function formatChannelProgressDraftText(params: {
   const maxLineChars = resolveChannelProgressDraftMaxLineChars(params.entry);
   const formatLine = params.formatLine ?? ((line: string) => line);
   const bullet = params.bullet ?? "•";
+  const lineSeparator = params.lineSeparator ?? "\n";
   const rawLines: Array<string | ChannelProgressDraftLine | { draftLabel: string }> = resolvedLabel
     ? [{ draftLabel: resolvedLabel }, ...params.lines]
     : params.lines;
@@ -1090,7 +1096,7 @@ export function formatChannelProgressDraftText(params: {
     });
   const renderedLines = lines.map((line) => line.text).filter((line) => Boolean(line));
   if (renderedLines.length > 1 && lines[0]?.isLabelLine) {
-    return `${renderedLines[0]}\n\n${renderedLines.slice(1).join("\n")}`;
+    return `${renderedLines[0]}\n\n${renderedLines.slice(1).join(lineSeparator)}`;
   }
-  return renderedLines.join("\n");
+  return renderedLines.join(lineSeparator);
 }