Purpose

Fixes #44906.

Kimi-K2 emits tool calls as special-token markup (<|tool_calls_section_begin|> ... <|tool_call_argument_begin|> {...} <|tool_call_end|> ...) and relies on its tool parser to pull the JSON arguments back out. This works fine for tool_choice: "auto", but when the request names a function (or sets tool_choice: "required") the server takes the standard JSON path and copies the raw model output straight into the call arguments. So the arguments come back full of the markup instead of the actual JSON, which is exactly what the issue reports.

The Kimi parser was inheriting the default supports_required_and_named = True, which tells the server the model already produces clean JSON for named and required tool choice. That is not true for this format. Setting it to False routes named and required choices through extract_tool_calls instead, the same way the GLM4-MoE parsers already handle their markup-based format. The change is a one line flag on KimiK2ToolParser plus a regression test.

Test Plan

pytest tests/tool_parsers/test_kimi_k2_tool_parser.py

Test Result

The new test_named_and_required_routed_through_parser passes and the existing Kimi-K2 parser tests still pass. I also confirmed against the exact payload from the issue that once the named and required paths go through the parser, extract_tool_calls returns name=get_weather and arguments={"city": "Boston"} rather than the raw markup.