feat: add capture_screenshot_jpeg helper

agent-workspace/agent_helpers.py

@@ -5,3 +5,28 @@
 repo's default agent-workspace exists.
 """
 
+import base64
+from PIL import Image
+
+
+def capture_screenshot_jpeg(path=None, full=False, max_dim=None, quality=80):
+    """Save a JPEG of the current viewport. Much smaller than PNG — avoids
+    LLM API input-length limits on 2× displays.
+
+    quality: 0–100 (default 80). 80 is visually clean and ~5–10× smaller than PNG.
+    max_dim: proportional downscale if either side exceeds this (e.g. 1800).
+    """
+    # Lazy import to avoid circular dep: helpers loads us at module init.
+    from browser_harness.helpers import cdp
+    from browser_harness._ipc import _TMP
+
+    path = path or str(_TMP / "shot.jpg")
+    r = cdp("Page.captureScreenshot", format="jpeg", quality=quality,
+            captureBeyondViewport=full)
+    open(path, "wb").write(base64.b64decode(r["data"]))
+    if max_dim:
+        img = Image.open(path)
+        if max(img.size) > max_dim:
+            img.thumbnail((max_dim, max_dim))
+            img.save(path, format="JPEG", quality=quality)
+    return path