From 44fff9297dfe115c3b2b616322fea0a762c4c024 Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Thu, 17 Sep 2026 17:17:21 -0700
Subject: [PATCH] fix(a2a): narrow discovery status codes through a structural
 protocol

basedpyright cannot narrow the probe error through
isinstance(error, AgentCardResolutionError) while that class is imported
inside try/except ImportError, which left three reportAttributeAccessIssue
errors over the budget main now carries. A runtime-checkable Protocol with
the same status_code contract carries the narrowing instead, so the check
no longer depends on the possibly unbound SDK name and the import goes.
---
 litellm/a2a_protocol/card_resolver.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/litellm/a2a_protocol/card_resolver.py b/litellm/a2a_protocol/card_resolver.py
index 9ef73f6293e..8614c794ac4 100644
--- a/litellm/a2a_protocol/card_resolver.py
+++ b/litellm/a2a_protocol/card_resolver.py
@@ -6,7 +6,7 @@ Extends the A2A SDK's card resolver to support multiple well-known paths.
 
 from collections.abc import Mapping
 from types import MappingProxyType
-from typing import TYPE_CHECKING, Any, Final
+from typing import TYPE_CHECKING, Any, Final, Protocol, runtime_checkable
 
 from litellm._logging import verbose_logger
 from litellm.a2a_protocol.exceptions import A2AAgentCardDiscoveryError
@@ -24,7 +24,6 @@ AGENT_CARD_PATH_PARAM: Final = "agent_card_path"
 
 try:
     from a2a.client import A2ACardResolver as _A2ACardResolver
-    from a2a.client.errors import AgentCardResolutionError
     from a2a.utils.constants import (
         AGENT_CARD_WELL_KNOWN_PATH,
         PREV_AGENT_CARD_WELL_KNOWN_PATH,
@@ -33,11 +32,16 @@ except ImportError:
     pass
 
 
+@runtime_checkable
+class _HasStatusCode(Protocol):
+    status_code: int | None
+
+
 def _discovery_status_code(failures: tuple[tuple[str, Exception], ...]) -> int:
     statuses: Final = tuple(
         error.status_code
         for _, error in failures
-        if isinstance(error, AgentCardResolutionError) and error.status_code is not None and error.status_code != 404
+        if isinstance(error, _HasStatusCode) and error.status_code is not None and error.status_code != 404
     )
     return statuses[0] if statuses else 404