[Bugfix] Hermes tool parser: parse tool call JSON by object boundary, not literal </tool_call>#45168
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extract_tool_calls slices each call up to the first literal </tool_call> (non-greedy tool_call_regex). A literal </tool_call> inside a JSON string argument -- e.g. arguments echoing user or document content -- truncates the string, json.loads fails, and the call is silently dropped. Reproduces after a real tokenize/detokenize round-trip on Qwen2.5 and Kanana-2. Parse each call with json.JSONDecoder().raw_decode() from just after <tool_call>; raw_decode respects string escaping, so a literal </tool_call> inside a string argument no longer truncates the call. The decoded object must be followed by </tool_call> or end-of-output; otherwise (concatenated objects, trailing junk, a missing end tag between calls) extraction falls back to content, matching the previous behavior. The streaming path shares the root cause; follow-up. Signed-off-by: jeongmingi <incheonkirin@gmail.com>
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Partially addresses #45167 (non-streaming path; streaming is tracked there as a follow-up).
Purpose
Hermes2ProToolParser.extract_tool_callsextracts each tool call by slicing up to the first literal</tool_call>(the non-greedytool_call_regex). When a tool argument's JSON string value contains that literal -- which happens when arguments echo user or document content (RAG, code-editing tools) -- the slice cuts the string short,json.loadssees invalid JSON, and the call is silently dropped (tools_called=False). This reproduces after a real tokenize->detokenize round-trip on bothQwen/Qwen2.5-0.5Bandkakaocorp/kanana-2-30b-a3b-instruct-2601(repro in the issue).This PR parses each call with
json.JSONDecoder().raw_decode()from just after<tool_call>, which respects JSON string escaping and stops at the object's real boundary, so an embedded</tool_call>is preserved. Behavior on malformed input is unchanged: if the decoded object isn't followed by the end tag or end-of-string, extraction raises and falls back to content -- the same outcome the oldjson.loadsproduced (concatenated objects, trailing junk, and a missing end tag between calls are all rejected as before).Scope: non-streaming only. The streaming path has the same root cause, but a naive
raw_decodeswap there regresses at some stream intervals (partial_tag_overlapmistakes a literal</tool_callinside an unclosed JSON string for a partial end tag) -- caught by my own streaming regression test during development. It needs a JSON-aware incremental scanner, planned as a follow-up in the issue.Test Plan
pytest tests/tool_parsers/test_hermes_tool_parser.pyAdds
test_hermes_parser_non_streaming_literal_end_tag_in_string(a literal</tool_call>inside a Korean JSON string argument) andtest_hermes_parser_non_streaming_trailing_data_falls_back_to_content(trailing prose, concatenated objects, and a missing end tag between calls still fall back to content).Test Result
The literal-tag test fails on
main(call dropped,tools_called=False) and passes with this change, recovering{"content": "예시 태그: </tool_call> 포함 한국어 본문"}intact. Full suite: 34 passed, 1 skipped locally -- 30 pre-existing tests unchanged plus 4 new test instances (macOS; the global-cleanup teardown fixture is skipped due to an unrelated torch/MPSempty_cacheissue -- test bodies all run, and CI runs the full suite as-is).