From d90a94ad165b9e49fda18f2f92aefdf950ba8b03 Mon Sep 17 00:00:00 2001
From: Vincent Koc <vincentkoc@ieee.org>
Date: Sat, 6 Jun 2026 08:23:55 -0700
Subject: [PATCH] fix(channels): strip dangling progress italics

---
 src/channels/streaming.ts                | 21 +++++++++++++++++++--
 src/plugin-sdk/channel-streaming.test.ts | 16 ++++++++++++++++
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/channels/streaming.ts b/src/channels/streaming.ts
index 073f5e26bbf5..ed9c5aa76f9d 100644
--- a/src/channels/streaming.ts
+++ b/src/channels/streaming.ts
@@ -901,6 +901,23 @@ function removeUnbalancedInlineBackticks(value: string): string {
   return value.trimStart().startsWith("`") ? value.replaceAll("`", "'") : value.replaceAll("`", "");
 }
 
+function repairCompactedProgressMarkdown(value: string): string {
+  const withoutDanglingBackticks = removeUnbalancedInlineBackticks(value);
+  const trimmedStart = withoutDanglingBackticks.trimStart();
+  if (!trimmedStart.startsWith("_") || trimmedStart.endsWith("_")) {
+    return withoutDanglingBackticks;
+  }
+  const underscoreCount = Array.from(trimmedStart).filter((char) => char === "_").length;
+  if (underscoreCount % 2 === 0) {
+    return withoutDanglingBackticks;
+  }
+  const leadingWhitespace = withoutDanglingBackticks.slice(
+    0,
+    withoutDanglingBackticks.length - trimmedStart.length,
+  );
+  return `${leadingWhitespace}${trimmedStart.slice(1)}`;
+}
+
 function compactPlainProgressLine(line: string, maxChars: number): string {
   const head = sliceCodePoints(line, 0, maxChars - 1).trimEnd();
   const boundary = head.search(/\s+\S*$/u);
@@ -931,7 +948,7 @@ function compactChannelProgressDraftLine(line: string, maxChars: number): string
     }
     // Keep the stable tool label/icon visible while trimming volatile command
     // detail; this reduces progress draft edit churn in chat UIs.
-    return removeUnbalancedInlineBackticks(
+    return repairCompactedProgressMarkdown(
       `${prefix}${compactProgressLineDetail(detail, detailLimit)}`,
     );
   };
@@ -954,7 +971,7 @@ function compactChannelProgressDraftLine(line: string, maxChars: number): string
     }
   }
 
-  return removeUnbalancedInlineBackticks(compactPlainProgressLine(normalized, maxChars));
+  return repairCompactedProgressMarkdown(compactPlainProgressLine(normalized, maxChars));
 }
 
 function getProgressDraftLineText(line: string | ChannelProgressDraftLine): string {
diff --git a/src/plugin-sdk/channel-streaming.test.ts b/src/plugin-sdk/channel-streaming.test.ts
index b12bc1973455..19d23b725dc4 100644
--- a/src/plugin-sdk/channel-streaming.test.ts
+++ b/src/plugin-sdk/channel-streaming.test.ts
@@ -361,6 +361,22 @@ describe("channel-streaming", () => {
     ).toBe("Shelling\n\n• I'm checking whether the generated video exists or if the…");
   });
 
+  it("falls back to plain commentary when compaction drops the closing italic marker", () => {
+    expect(
+      formatChannelProgressDraftText({
+        entry: { streaming: { progress: { label: false, maxLineChars: 32 } } },
+        lines: [
+          {
+            kind: "item",
+            text: `_${"x".repeat(80)}_`,
+            label: "Commentary",
+            prefix: false,
+          },
+        ],
+      }),
+    ).toBe(`${"x".repeat(30)}…`);
+  });
+
   it("keeps compacted raw progress lines from leaking unmatched markdown backticks", () => {
     const line = buildChannelProgressDraftLine(
       {