parse_tool_blocks fed <tool_call> wrapper bodies only to the XML
iterators (_iter_xml_invoke/_iter_xml_direct), so the canonical
Qwen/Hermes text-mode form — a bare JSON object like
{"name": "bash", "arguments": {"command": "..."}} inside the
wrapper — parsed to zero tool blocks and the agent never executed
anything. Pattern 4d only matches OpenAI-style blobs with a literal
"function" key, which the Hermes format lacks.
Wrapper bodies are now classified first: a JSON-looking body ({ or [)
is parsed by the new _parse_json_tool_call_body, which requires an
object with a string "name" and rejects a non-object "arguments"
instead of coercing it, then converts through the same
function_call_to_tool_block used by the XML paths so aliases and
per-tool argument formatting stay uniform. JSON-looking bodies fail
closed — they are never rescanned by the XML iterators (including the
unclosed-wrapper and bare-invoke fallbacks), so XML-like text inside
JSON argument values stays data instead of selecting a different tool.
Non-JSON bodies keep the existing XML path unchanged.
Fixes#5187
Co-authored-by: Alexandre Teixeira <111787685+alteixeira20@users.noreply.github.com>
