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Merged
ServeurpersoCom merged 6 commits into from
Jun 15, 2026
Merged

chat: harden peg-native tool call parsing #24329

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752a9bc
chat: harden peg-native tool call parsing
ServeurpersoCom Jun 9, 2026
39956dc
chat: surface peg-native parse failures
ServeurpersoCom Jun 9, 2026
6dd339e
chat: handle openai style tool calls in peg-native
ServeurpersoCom Jun 9, 2026
d56e988
nits
ServeurpersoCom Jun 9, 2026
c2cfb28
common: scope OpenAI wrapper grammar trigger via autoparser flag
ServeurpersoCom Jun 9, 2026
07b23d6
chat: gate type:function parsing leniency on the analysis flag
ServeurpersoCom Jun 10, 2026
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8 changes: 6 additions & 2 deletions common/chat-auto-parser-generator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,10 @@ common_chat_params peg_generator::generate_parser(const common_chat_template &
data.grammar_triggers = {
{ COMMON_GRAMMAR_TRIGGER_TYPE_WORD, trigger_marker }
};
if (autoparser.tools.format.openai_wrapper_trigger) {
// model emits the OpenAI function wrapper, trigger on it
data.grammar_triggers.push_back({ COMMON_GRAMMAR_TRIGGER_TYPE_WORD, "{\"type\": \"function\"," });
}
}
}

Expand Down Expand Up @@ -224,13 +228,13 @@ common_peg_parser analyze_tools::build_tool_parser_json_native(parser_build_cont
auto single_tool_parser = p.standard_json_tools(
format.per_call_start, format.per_call_end, inputs.tools, inputs.parallel_tool_calls,
inputs.tool_choice == COMMON_CHAT_TOOL_CHOICE_REQUIRED, name_field, args_field, format.tools_array_wrapped,
format.fun_name_is_key, format.id_field, format.gen_id_field, format.parameter_order);
format.fun_name_is_key, format.id_field, format.gen_id_field, format.parameter_order, format.openai_wrapper_trigger);
tools_parser = p.trigger_rule("tool-calls", p.one_or_more(single_tool_parser + p.space()));
} else {
tools_parser = p.standard_json_tools(
format.section_start, format.section_end, inputs.tools, inputs.parallel_tool_calls,
inputs.tool_choice == COMMON_CHAT_TOOL_CHOICE_REQUIRED, name_field, args_field, format.tools_array_wrapped,
format.fun_name_is_key, format.id_field, format.gen_id_field, format.parameter_order);
format.fun_name_is_key, format.id_field, format.gen_id_field, format.parameter_order, format.openai_wrapper_trigger);
}

// Handle content wrappers if present
Expand Down
1 change: 1 addition & 0 deletions common/chat-auto-parser.h
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Original file line number Diff line number Diff line change
Expand Up @@ -181,6 +181,7 @@ struct tool_format_analysis {

bool fun_name_is_key = false; // In JSON format function name is JSON key, i.e. { "<funname>": { ... arguments ... } }
bool tools_array_wrapped = false; // Tool calls wrapped in JSON array [...]
bool openai_wrapper_trigger = false; // model emits the OpenAI function wrapper, trigger on it

std::string function_field = "function";
std::string name_field = "name";
Expand Down
8 changes: 8 additions & 0 deletions common/chat-diff-analyzer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,14 @@ static std::vector<std::function<void(const common_chat_template & tmpl, autopar
LOG_DBG(ANSI_ORANGE "[Patch: Apriel 1.6]\n" ANSI_RESET);
}
},
// template uses the JSON {name, parameters} tool instruction, emits the OpenAI function wrapper
[](const common_chat_template & tmpl, autoparser & analysis) -> void {
if (tmpl.src.find("Respond in the format {\"name\": function name") != std::string::npos &&
tmpl.src.find("Do not use variables.") != std::string::npos) {
analysis.tools.format.openai_wrapper_trigger = true;
LOG_DBG(ANSI_ORANGE "[Patch: JSON name/parameters tool instruction]\n" ANSI_RESET);
}
},

});

Expand Down
16 changes: 12 additions & 4 deletions common/chat-peg-parser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -745,7 +745,8 @@ common_peg_parser common_chat_peg_builder::build_json_tools_flat_keys(
const std::string & effective_args_key,
const std::string & call_id_key,
const std::string & gen_call_id_key,
const std::vector<std::string> & parameters_order) {
const std::vector<std::string> & parameters_order,
bool accept_openai_wrapper) {

auto tool_choices = choice();
auto name_key_parser = literal("\"" + effective_name_key + "\"");
Expand Down Expand Up @@ -807,7 +808,13 @@ common_peg_parser common_chat_peg_builder::build_json_tools_flat_keys(
return idx_a < idx_b;
});

auto ordered_body = tool_open(literal("{")) + space();
// accept an optional leading "type": "function" field when the model emits the OpenAI wrapper
common_peg_parser type_field = eps();
if (accept_openai_wrapper) {
type_field = optional(literal("\"type\"") + space() + literal(":") + space() +
literal("\"function\"") + space() + literal(",") + space());
}
auto ordered_body = tool_open(literal("{")) + space() + type_field;
for (size_t i = 0; i < parser_pairs.size(); i++) {
ordered_body = ordered_body + parser_pairs[i].first;
if (i < parser_pairs.size() - 1) {
Expand Down Expand Up @@ -870,7 +877,8 @@ common_peg_parser common_chat_peg_builder::standard_json_tools(
bool function_is_key,
const std::string & call_id_key,
const std::string & gen_call_id_key,
const std::vector<std::string> & parameters_order) {
const std::vector<std::string> & parameters_order,
bool accept_openai_wrapper) {
if (!tools.is_array() || tools.empty()) {
return eps();
}
Expand All @@ -888,7 +896,7 @@ common_peg_parser common_chat_peg_builder::standard_json_tools(
if (!name_spec.first.empty() || !args_spec.first.empty()) {
tool_choices = build_json_tools_nested_keys(tools, effective_name_key, effective_args_key, call_id_key, gen_call_id_key);
} else {
tool_choices = build_json_tools_flat_keys(tools, effective_name_key, effective_args_key, call_id_key, gen_call_id_key, parameters_order);
tool_choices = build_json_tools_flat_keys(tools, effective_name_key, effective_args_key, call_id_key, gen_call_id_key, parameters_order, accept_openai_wrapper);
}
}

Expand Down
6 changes: 4 additions & 2 deletions common/chat-peg-parser.h
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Original file line number Diff line number Diff line change
Expand Up @@ -120,7 +120,8 @@ class common_chat_peg_builder : public common_peg_parser_builder {
bool function_is_key = false,
const std::string & call_id_key = "",
const std::string & gen_call_id_key = "",
const std::vector<std::string> & parameters_order = {});
const std::vector<std::string> & parameters_order = {},
bool accept_openai_wrapper = false);

// Legacy-compatible helper for building XML/tagged style tool calls
// Used by tests and manual parsers
Expand Down Expand Up @@ -157,7 +158,8 @@ class common_chat_peg_builder : public common_peg_parser_builder {
const std::string & effective_args_key,
const std::string & call_id_key,
const std::string & gen_call_id_key,
const std::vector<std::string> & parameters_order);
const std::vector<std::string> & parameters_order,
bool accept_openai_wrapper);
};

inline common_peg_arena build_chat_peg_parser(
Expand Down
6 changes: 4 additions & 2 deletions common/chat.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2520,8 +2520,10 @@ common_chat_msg common_chat_peg_parse(const common_peg_arena & src_pars
}
return msg;
}
throw std::runtime_error(std::string("Failed to parse input at pos ") + std::to_string(result.end) + ": " +
effective_input.substr(result.end));
LOG_WRN("%s: unparsed %s output: %s\n", __func__, common_chat_format_name(params.format),
effective_input.substr(result.end).c_str());
throw std::runtime_error(std::string("The model produced output that does not match the expected ") +
common_chat_format_name(params.format) + " format");
}

common_chat_msg msg;
Expand Down
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