From d04b075996d3c724e4373997ac84a93a2a1781ad Mon Sep 17 00:00:00 2001
From: Dai Ha <dai.ha@magnolia-cms.com>
Date: Sat, 15 Aug 2026 04:25:54 +0200
Subject: [PATCH] CB-563: mark clipped completion scrapes

---
 .../bridged/inject/CompletionResolver.java    | 18 +++++++++--
 .../inject/CompletionResolverTest.java        | 30 ++++++++++++++++++-
 2 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/bridged/src/main/java/dev/ltms/bridged/inject/CompletionResolver.java b/bridged/src/main/java/dev/ltms/bridged/inject/CompletionResolver.java
index 87fcf6c..d97a5bf 100644
--- a/bridged/src/main/java/dev/ltms/bridged/inject/CompletionResolver.java
+++ b/bridged/src/main/java/dev/ltms/bridged/inject/CompletionResolver.java
@@ -55,6 +55,9 @@ public final class CompletionResolver implements TurnListener {
     /** Cap the scraped tail so a long transcript can't return an unbounded blob. */
     static final int MAX_SCRAPE_CHARS = 4000;
 
+    private static final String CLIPPED_PANE_TAIL_MARKER =
+            "[Pane tail clipped: member did not call bridge_reply.]";
+
     private final AgentControl agents;
     private final Rendezvous rendezvous;
 
@@ -147,9 +150,14 @@ public final class CompletionResolver implements TurnListener {
             return;
         }
         String tail;
+        int originalLength = 0;
+        boolean clipped = false;
         boolean scrapeFailed = false;
         try {
-            tail = clip(lastAssistantBlock(agents.read(target, SCRAPE_SOURCE)));
+            String assistantBlock = lastAssistantBlock(agents.read(target, SCRAPE_SOURCE));
+            originalLength = assistantBlock.strip().length();
+            clipped = originalLength > MAX_SCRAPE_CHARS;
+            tail = clip(assistantBlock);
         } catch (RuntimeException e) {
             // The worker finished but we couldn't read its screen — still resolve the send so the
             // caller unblocks; an empty tail beats hanging until the caller's timeout.
@@ -169,8 +177,14 @@ public final class CompletionResolver implements TurnListener {
                     target);
             return; // keep the in-flight record: a later genuine completion still needs it
         }
-        if (rendezvous.resolveCompletion(waiter, tail)) {
+        String completion = clipped ? tail + "\n" + CLIPPED_PANE_TAIL_MARKER : tail;
+        if (rendezvous.resolveCompletion(waiter, completion)) {
             inFlight.remove(target, turn);
+            if (clipped) {
+                log.warn("completion scrape for {} clipped from {} chars to the {} char cap; "
+                                + "member did not call bridge_reply, so the pane tail is partial",
+                        target, originalLength, MAX_SCRAPE_CHARS);
+            }
             log.debug("resolved send to {} via turn-completion fallback ({} chars scraped)",
                     target, tail.length());
         }
diff --git a/bridged/src/test/java/dev/ltms/bridged/inject/CompletionResolverTest.java b/bridged/src/test/java/dev/ltms/bridged/inject/CompletionResolverTest.java
index 8462072..c7dd2fe 100644
--- a/bridged/src/test/java/dev/ltms/bridged/inject/CompletionResolverTest.java
+++ b/bridged/src/test/java/dev/ltms/bridged/inject/CompletionResolverTest.java
@@ -156,6 +156,33 @@ class CompletionResolverTest {
         assertEquals("No, 391 = 17 × 23.", waiter.getNow(null).text());
     }
 
+    @Test
+    void marksAClippedCompletionPaneTail() {
+        String block = "⏺ " + "x".repeat(CompletionResolver.MAX_SCRAPE_CHARS + 1) + "\n❯ ";
+        FakeHerdr herdr = new FakeHerdr().readText(block);
+        Rendezvous rendezvous = new Rendezvous();
+        CompletionResolver resolver = new CompletionResolver(new AgentControl(herdr), rendezvous);
+
+        var waiter = rendezvous.open("term_a");
+        resolver.resolve("term_a", new CompletionResolver.InFlight(waiter, null));
+
+        assertEquals("x".repeat(CompletionResolver.MAX_SCRAPE_CHARS)
+                        + "\n[Pane tail clipped: member did not call bridge_reply.]",
+                waiter.getNow(null).text());
+    }
+
+    @Test
+    void leavesAnUnclippedCompletionPaneTailUnmarked() {
+        FakeHerdr herdr = new FakeHerdr().readText("⏺ complete report\n❯ ");
+        Rendezvous rendezvous = new Rendezvous();
+        CompletionResolver resolver = new CompletionResolver(new AgentControl(herdr), rendezvous);
+
+        var waiter = rendezvous.open("term_a");
+        resolver.resolve("term_a", new CompletionResolver.InFlight(waiter, null));
+
+        assertEquals("complete report", waiter.getNow(null).text());
+    }
+
     @Test
     void resolvesSynchronouslyBeforePostTurnContextClearing() {
         FakeHerdr herdr = new FakeHerdr().readText("⏺ previous answer\n❯ ");
@@ -177,7 +204,8 @@ class CompletionResolverTest {
         // block while resolve compares against a clip()'d tail. For a block longer than MAX_SCRAPE_CHARS
         // the two capped representations differ even when the pane never changed, so the CB-115
         // byte-identical guard failed to fire and a stale completion could resolve the send. Both sides
-        // must clip identically; here an unchanged >cap block on rapid back-to-back turns stays suppressed.
+        // must clip identically. The returned-text marker is added only after this comparison, so an
+        // unchanged >cap block on rapid back-to-back turns still stays suppressed.
         String longBlock = "⏺ " + "x".repeat(CompletionResolver.MAX_SCRAPE_CHARS + 500) + "\n❯ ";
         FakeHerdr herdr = new FakeHerdr().readText(longBlock);
         Rendezvous rendezvous = new Rendezvous();