- Declare `supports_vision_tool_messages=False` and `supports_vision=True` on `opencode_go` provider profile in `plugins/model-providers/opencode-zen/__init__.py`
- Route HTTP 422 errors through `_IMAGE_TOOL_RULES` and add `tool.content.str`, `tool.content`, and `input should be a valid string` patterns to `_MULTIMODAL_TOOL_CONTENT_PATTERNS` in `agent/error_classifier.py`
- Add unit tests for OpenCode Go proactive tool result downgrade, HTTP 422 Console Go classification, and profile capability contract in `tests/run_agent/test_multimodal_tool_content_recovery.py` and `tests/plugins/model_providers/test_opencode_go_profile.py`