common/chat : unify and fix LFM2/LFM2.5 tool parser#24178
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tdakhran wants to merge 1 commit into
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LFM2 and LFM2.5 share the same tool-calling format with the only difference is that LFM2 also wraps the system tool list in <|tool_list_start|>/<|tool_list_end|>. Merge the two parsers into common_chat_params_init_lfm2(..., tool_list_tokens). Also fix and extend argument parsing: * convert Python literals True/False/None to JSON true/false/null * accept JSON-cased true/false/null in argument values * convert single-quoted strings to JSON strings * handle dotted function names, e.g. Calendar.create_event // insert image here
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I'd love to see this merged. IMHO the conversion of the literals from Python to JSON could solve problems that many people seem to have when it comes to LFM2.5 tool calling. As described in this issue over at HF. |
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Related: #24071 |
pwilkin
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Jun 5, 2026
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pwilkin
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I swear everything just operates in cycles - back in the day we had a full python dict parser in the autoparser code, but we removed it because we figured nobody uses that syntax anymore... ;)
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CC @aldehir if you can do a quick review |
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Overview
LFM2 and LFM2.5 share the same pythonic style tool-calling format, with the only difference being that LFM2 also wraps the system tool list in <|tool_list_start|>/<|tool_list_end|>.
Two parsers are merged into
common_chat_params_init_lfm2(..., tool_list_tokens)and share logic.Also fix and extend argument parsing:
Calendar.create_eventAdditional information
The parser was tested against the reference implementation and recovers tool-calling capabilities across different LFM2/LFM2.5 models. Interactive HTML with comparison attached below.
lfm2_tool_calling_7fe2ae45a_vs_71b74a408.html
Requirements