fix(web): hide injected system asides in user message bubbles

.changeset/hide-web-system-asides.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+web: Hide the internal image-compression note so it no longer renders as user message text.

apps/kimi-web/src/composables/messagesToTurns.ts

@@ -25,6 +25,24 @@ const USER_MEDIA_PATH_TAG_RE = /^<(image|video|audio)\s+path="([^"]+)">(?:<\/\1>
 const SYSTEM_MIME_RE = /Mime type:\s*([^.\s]+)/i;
 const SYSTEM_SIZE_RE = /Size:\s*(\d+)\s*bytes/i;
 const SYSTEM_DIMENSIONS_RE = /Original dimensions:\s*(\d+)x(\d+)\s*pixels/i;
+// agent-core inlines a single model-facing `<system>` caption next to a
+// compressed image upload (buildImageCompressionCaption), which rides along as
+// a text part of the persisted user message. That one caption is harness
+// metadata, not something the user typed, and its raw markup must never reach
+// the bubble (or the edit/preview text derived from `turn.text`). The TUI and
+// agent-core strip ONLY that caption — anchored on its fixed opening
+// `<system>Image compressed to fit model limits:` (see
+// extractImageCompressionCaptions in agent-core) — and reroute it through the
+// hidden system-reminder injection. Mirror that narrow targeting here: a
+// literal `<system>…</system>` the user pasted themselves (e.g. an XML / prompt
+// example) is their own text, not harness metadata, so it survives untouched.
+const CAPTION_OPENING = '<system>Image compressed to fit model limits:';
+const CAPTION_PATTERN = /<system>Image compressed to fit model limits:[\s\S]*?<\/system>/g;
+
+function stripImageCompressionCaptions(text: string): string {
+  if (!text.includes(CAPTION_OPENING)) return text;
+  return text.replace(CAPTION_PATTERN, '');
+}
 
 function unescapeAttr(value: string): string {
   // &amp; last so a doubly-escaped value isn't decoded twice.
@@ -698,7 +716,9 @@ export function messagesToTurns(
                 continue;
               }
             }
-            textParts.push(c.text);
+            const stripped = stripImageCompressionCaptions(c.text);
+            if (stripped !== c.text && stripped.trim().length === 0) continue;
+            textParts.push(stripped);
           }
         }
         const media = resolveMediaUrl(c);

apps/kimi-web/test/turn-logic.test.ts

@@ -206,6 +206,94 @@ describe('messagesToTurns', () => {
     expect(turns[0]).toMatchObject({ role: 'user', text: tag });
     expect(turns[0]?.images).toBeUndefined();
   });
+
+  it('strips the hidden image-compression caption from a user bubble', () => {
+    // The server persists this `<system>` note as its own text part next to a
+    // compressed upload (buildImageCompressionCaption). It is model-facing
+    // harness metadata and must never render as user-typed text.
+    const caption =
+      '<system>Image compressed to fit model limits: original 3024x1834 image/png (934 KB) -> ' +
+      'sent 2000x1213 image/png (518 KB). Fine detail may be lost. The uncompressed original ' +
+      'is saved at "/Users/me/.kimi-code/files/f_0000000000000000000000000"; if you need fine ' +
+      'detail, call ReadMediaFile on that path with the region parameter to view a crop at full ' +
+      'fidelity.</system>';
+    const turns = messagesToTurns(
+      [
+        message('u1', 'user', [
+          { type: 'text', text: 'look at this' },
+          { type: 'text', text: caption },
+        ]),
+      ],
+      [],
+      undefined,
+      false,
+    );
+
+    expect(turns).toHaveLength(1);
+    expect(turns[0]).toMatchObject({ role: 'user', text: 'look at this' });
+    expect(turns[0]?.text).not.toContain('<system>');
+  });
+
+  it('drops a caption-only text part and strips captions merged into prose', () => {
+    const caption =
+      '<system>Image compressed to fit model limits: original 100x100 image/png (1 KB) -> ' +
+      'sent 100x100 image/png (1 KB). Fine detail may be lost.</system>';
+
+    // Image-only upload: the caption is the sole text part, so nothing
+    // user-typed remains and the bubble text is empty (the image still renders).
+    const captionOnly = messagesToTurns(
+      [message('u1', 'user', [{ type: 'text', text: caption }])],
+      [],
+      undefined,
+      false,
+    );
+    expect(captionOnly[0]).toMatchObject({ role: 'user', text: '' });
+
+    // TUI-paste style: a caption merged into the surrounding text segment is
+    // stripped without eating the prose around it.
+    const merged = messagesToTurns(
+      [message('u2', 'user', [{ type: 'text', text: `before ${caption} after` }])],
+      [],
+      undefined,
+      false,
+    );
+    expect(merged[0]?.text).not.toContain('<system>');
+    expect(merged[0]?.text).toContain('before');
+    expect(merged[0]?.text).toContain('after');
+  });
+
+  it('preserves a literal `<system>` block the user typed themselves', () => {
+    // Only the image-compression caption is harness metadata. A `<system>` tag
+    // the user pasted on purpose (e.g. an XML / prompt example) is their own
+    // text, so it must reach the bubble and the edit/resend payload verbatim.
+    const turns = messagesToTurns(
+      [
+        message('u1', 'user', [
+          { type: 'text', text: 'hi <system>some example markup</system> there' },
+        ]),
+      ],
+      [],
+      undefined,
+      false,
+    );
+
+    expect(turns[0]?.text).toBe('hi <system>some example markup</system> there');
+  });
+
+  it('leaves ordinary user text and stray angle brackets untouched', () => {
+    const turns = messagesToTurns(
+      [
+        message('u1', 'user', [
+          { type: 'text', text: 'a < b and c > d, no system tag here' },
+        ]),
+      ],
+      [],
+      undefined,
+      false,
+    );
+
+    expect(turns[0]).toMatchObject({ role: 'user', text: 'a < b and c > d, no system tag here' });
+  });
 });
 
 describe('latestTodos', () => {