The document_query tool logs its message as its own `document_query` type with an `icon://manage_search Querying: <document>` headline when queries are supplied and `Reading: <document>` without them, naming the first document and appending `+ N more` for multi-document queries. A plugin message handler renders it as a DOC badge with blue and blue-violet accents across modes, each clearly bluer than the a2a chat family so document queries read like the other dedicated tool surfaces. Agent-facing failure messages render from plugin prompt files, and the Q&A answer streams into the tool log while the model writes it; helpers built without the streaming callback still answer without streaming. Regression tests cover the log entry, headline words, and empty-query reading mode.
Validation: pytest tests/test_document_query_tool_ui.py tests/test_document_query_fallback.py
