fix: deduplicate progress at runner level, not host revert

Buffer intermediate assistant text in the runner. When result arrives
with matching text, discard the buffered progress instead of emitting
it. This prevents the duplicate from ever reaching Discord, eliminating
the flash-then-revert behavior.

runners/agent-runner/src/index.ts

@@ -452,6 +452,7 @@ async function runQuery(
   let messageCount = 0;
   let resultCount = 0;
   let terminalResultObserved = false;
+  let pendingProgressText: string | null = null;
 
   // Discover additional directories
   const extraDirs: string[] = [];
@@ -541,6 +542,18 @@ async function runQuery(
     const msgType = message.type === 'system' ? `system/${(message as { subtype?: string }).subtype}` : message.type;
     log(`[msg #${messageCount}] type=${msgType}`);
 
+    // Flush pending progress on any non-assistant message (ensures it's
+    // emitted before tool-activity or other events that depend on it).
+    if (message.type !== 'assistant' && pendingProgressText) {
+      writeOutput({
+        status: 'success',
+        phase: 'progress',
+        result: pendingProgressText,
+        newSessionId,
+      });
+      pendingProgressText = null;
+    }
+
     if (message.type === 'system' && message.subtype === 'init') {
       newSessionId = message.session_id;
       log(`Session initialized: ${newSessionId}`);
@@ -609,6 +622,14 @@ async function runQuery(
       resultCount++;
       const textResult = 'result' in message ? (message as { result?: string }).result : null;
       const isError = message.subtype?.startsWith('error');
+      // Discard pending progress if it matches the final result (prevent duplicate)
+      if (pendingProgressText && textResult && pendingProgressText === textResult) {
+        log(`Discarding pending progress (matches result)`);
+        pendingProgressText = null;
+      } else if (pendingProgressText) {
+        writeOutput({ status: 'success', phase: 'progress', result: pendingProgressText, newSessionId });
+        pendingProgressText = null;
+      }
       log(`Result #${resultCount}: subtype=${message.subtype}${textResult ? ` text=${textResult.slice(0, 200)}` : ''}`);
       if (isError) {
         // Log full error details for debugging
@@ -672,15 +693,22 @@ async function runQuery(
         stream.end();
         break;
       }
-      // Intermediate assistant text between tool calls → progress
+      // Intermediate assistant text between tool calls → buffer as pending progress.
+      // Don't emit immediately — if the next message is a result with the same text,
+      // this would cause a duplicate. The pending text is flushed when the next
+      // non-result message arrives, or discarded if result matches.
       if (stopReason !== 'end_turn' && textResult) {
-        log(`Intermediate assistant text (${textResult.length} chars, stop=${stopReason})`);
-        writeOutput({
-          status: 'success',
-          phase: 'progress',
-          result: textResult,
-          newSessionId,
-        });
+        // Flush any previous pending progress first
+        if (pendingProgressText) {
+          writeOutput({
+            status: 'success',
+            phase: 'progress',
+            result: pendingProgressText,
+            newSessionId,
+          });
+        }
+        pendingProgressText = textResult;
+        log(`Intermediate assistant text buffered (${textResult.length} chars, stop=${stopReason})`);
       }
     }
   }

src/message-turn-controller.ts

@@ -154,18 +154,6 @@ export class MessageTurnController {
     // then discard the pending buffer so it never shows up.
     if (text) {
       await this.flushPendingProgress(text);
-      // If the displayed progress heading matches the final text,
-      // revert to the previous heading so it doesn't show twice.
-      if (
-        this.latestProgressText === text &&
-        this.previousProgressText &&
-        this.progressMessageId &&
-        this.options.channel.editMessage
-      ) {
-        this.latestProgressText = this.previousProgressText;
-        this.toolActivities = [];
-        await this.syncTrackedProgressMessage();
-      }
       await this.finalizeProgressMessage();
       await this.deliverFinalText(text);
     } else if (raw) {