From 4f736d81ad60788aaa63f8bfe2e292800a3cb7be Mon Sep 17 00:00:00 2001
From: Alexander Alderman Webb <alexander.webb@sentry.io>
Date: Tue, 27 Jan 2026 09:59:56 +0100
Subject: [PATCH 1/3] feat(transport): Report 413 responses for oversized
 envelopes

---
 sentry_sdk/transport.py | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/sentry_sdk/transport.py b/sentry_sdk/transport.py
index cee4fa882b..dcfe55406b 100644
--- a/sentry_sdk/transport.py
+++ b/sentry_sdk/transport.py
@@ -340,7 +340,21 @@ def record_loss(reason: str) -> None:
         try:
             self._update_rate_limits(response)
 
-            if response.status == 429:
+            if response.status == 413:
+                size_exceeded_message = (
+                    "HTTP 413: Event dropped due to exceeded envelope size limit"
+                )
+                response_message = getattr(
+                    response, "data", getattr(response, "content", None)
+                )
+                if response_message is not None:
+                    size_exceeded_message += f" (body: {response_message})"
+
+                logger.error(size_exceeded_message)
+                self.on_dropped_event("status_413")
+                record_loss("send_error")
+
+            elif response.status == 429:
                 # if we hit a 429.  Something was rate limited but we already
                 # acted on this in `self._update_rate_limits`.  Note that we
                 # do not want to record event loss here as we will have recorded

From 56c019cda704eb35b2159dce0f6490530d4c6fb4 Mon Sep 17 00:00:00 2001
From: Alexander Alderman Webb <alexander.webb@sentry.io>
Date: Tue, 27 Jan 2026 16:07:39 +0100
Subject: [PATCH 2/3] add test

---
 tests/test_transport.py | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tests/test_transport.py b/tests/test_transport.py
index b5b88e0e2c..411bccc9b5 100644
--- a/tests/test_transport.py
+++ b/tests/test_transport.py
@@ -385,6 +385,33 @@ def test_parse_rate_limits(input, expected):
     assert dict(_parse_rate_limits(input, now=NOW)) == expected
 
 
+def test_envelope_too_large_response(capturing_server, make_client):
+    client = make_client()
+
+    capturing_server.respond_with(code=413)
+    client.capture_event({"type": "error"})
+    client.capture_event({"type": "transaction"})
+    client.flush()
+
+    # Error, transaction, and client report payloads
+    assert len(capturing_server.captured) == 3
+    report = parse_json(capturing_server.captured[2].envelope.items[0].get_bytes())
+
+    # Client reports for transaction and included span
+    assert len(report["discarded_events"]) == 3
+    assert {"reason": "send_error", "category": "error", "quantity": 1} in report[
+        "discarded_events"
+    ]
+    assert {"reason": "send_error", "category": "span", "quantity": 1} in report[
+        "discarded_events"
+    ]
+    assert {"reason": "send_error", "category": "transaction", "quantity": 1} in report[
+        "discarded_events"
+    ]
+
+    capturing_server.clear_captured()
+
+
 def test_simple_rate_limits(capturing_server, make_client):
     client = make_client()
     capturing_server.respond_with(code=429, headers={"Retry-After": "4"})

From 030886d375ae1ffadbdbcfd9573a5ec6b07b560e Mon Sep 17 00:00:00 2001
From: Alexander Alderman Webb <alexander.webb@sentry.io>
Date: Tue, 27 Jan 2026 16:08:25 +0100
Subject: [PATCH 3/3] docstring

---
 tests/test_transport.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/test_transport.py b/tests/test_transport.py
index 411bccc9b5..8601a4f138 100644
--- a/tests/test_transport.py
+++ b/tests/test_transport.py
@@ -397,7 +397,7 @@ def test_envelope_too_large_response(capturing_server, make_client):
     assert len(capturing_server.captured) == 3
     report = parse_json(capturing_server.captured[2].envelope.items[0].get_bytes())
 
-    # Client reports for transaction and included span
+    # Client reports for error, transaction and included span
     assert len(report["discarded_events"]) == 3
     assert {"reason": "send_error", "category": "error", "quantity": 1} in report[
         "discarded_events"