diff --git a/agent/reviewer_publish.py b/agent/reviewer_publish.py
index f0222a13..f608efb1 100644
--- a/agent/reviewer_publish.py
+++ b/agent/reviewer_publish.py
@@ -122,9 +122,20 @@ async def post_pull_request_review(
         try:
             response = await client.post(url, headers=headers, json=payload, timeout=30)
             response.raise_for_status()
-        except httpx.HTTPError:
+        except httpx.HTTPStatusError as e:
+            body = (e.response.text or "")[:500]
+            logger.exception(
+                "Failed to POST PR review for %s/%s#%s: %s %s",
+                owner,
+                repo,
+                pr_number,
+                e.response.status_code,
+                body,
+            )
+            return {"_error": f"HTTP {e.response.status_code}: {body}"}
+        except httpx.HTTPError as e:
             logger.exception("Failed to POST PR review for %s/%s#%s", owner, repo, pr_number)
-            return None
+            return {"_error": f"{type(e).__name__}: {e}"}
     data = response.json()
     return data if isinstance(data, dict) else None
 
diff --git a/agent/tools/publish_review.py b/agent/tools/publish_review.py
index 2c3566f3..5f32f00a 100644
--- a/agent/tools/publish_review.py
+++ b/agent/tools/publish_review.py
@@ -159,6 +159,11 @@ async def _publish_review_async(
     )
     if review_response is None:
         return {"success": False, "error": "Failed to POST PR review"}
+    if isinstance(review_response, dict) and "_error" in review_response:
+        return {
+            "success": False,
+            "error": f"Failed to POST PR review: {review_response['_error']}",
+        }
     review_id = review_response.get("id") if isinstance(review_response, dict) else None
 
     if review_id is not None and inline_comments: