fix: trim opencode-go 422 salvage to the invariant set

Drop the bare "tool.content" pattern (any 400 mentioning tool.content in a
non-list context would be sent through the image-strip path) and the profile
flag snapshot test; the behaviour tests (classifier verdict + proactive
downgrade) already pin the contract.

agent/error_classifier.py

@@ -169,8 +169,8 @@ _IMAGE_CORRUPT_PATTERNS = (
 _MULTIMODAL_TOOL_CONTENT_PATTERNS = (
     "text is not set", "tool message content must be a string", "tool content must be a string",
     "tool message must be a string", "expected string, got list", "expected string, got array",
-    "tool_call.content must be string", "tool.content.str", "tool.content",
-    "input should be a valid string",
+    # Console Go / pydantic-v2 relays behind opencode-go (422, param ``messages.N.tool.content.str``, #104731).
+    "tool_call.content must be string", "tool.content.str", "input should be a valid string",
 )
 
 # Local-inference memory/resource-ceiling rejections (oMLX/MLX memory guard,

tests/plugins/model_providers/test_opencode_go_profile.py

@@ -254,11 +254,3 @@ class TestOpenCodeGoFullKwargsIntegration:
         assert "extra_body" not in kwargs
         assert kwargs["reasoning_effort"] == "high"
 
-
-class TestOpenCodeGoVisionToolMessages:
-    """OpenCode Go provider profile declares supports_vision_tool_messages=False (#104731)."""
-
-    def test_supports_vision_true_and_tool_messages_false(self, opencode_go_profile):
-        assert opencode_go_profile.supports_vision is True
-        assert opencode_go_profile.supports_vision_tool_messages is False
-