diff --git a/common/chat.cpp b/common/chat.cpp
index c2ca17c743..7536c0cd01 100644
--- a/common/chat.cpp
+++ b/common/chat.cpp
@@ -1274,11 +1274,12 @@ static common_chat_params common_chat_params_init_kimi_k2(const common_chat_temp
return data;
}
-// LFM2 format:
-// - Reasoning: {reasoning} (optional, only if enable_thinking is true)
-// - Content: text after reasoning (optional)
-// - Tool calls: <|tool_call_start|>[function_name(arg1="value1", arg2="value2")]<|tool_call_end|>
-// Tool calls can appear multiple times (parallel tool calls)
+// LFM2 format: uses <|tool_list_start|>[...]<|tool_list_end|> in system prompt
+// and <|tool_call_start|>[name(arg="val")]<|tool_call_end|> for tool calls.
+// - Reasoning: {reasoning} (optional)
+// - Content: text before a tool call (optional)
+// - Tool calls: Python-style, e.g. [function_name(arg1="value1", arg2="value2")]
+// Tool calls can appear multiple times (parallel tool calls supported)
static common_chat_params common_chat_params_init_lfm2(const common_chat_template & tmpl,
const autoparser::generation_params & inputs) {
common_chat_params data;
@@ -1319,9 +1320,9 @@ static common_chat_params common_chat_params_init_lfm2(const common_chat_templat
if (!has_tools || inputs.tool_choice == COMMON_CHAT_TOOL_CHOICE_NONE) {
return generation_prompt + reasoning + p.content(p.rest()) + end;
}
-
auto tool_calls = p.rule("tool-calls",
- p.trigger_rule("tool-call", p.literal(TOOL_CALL_START) +
+ p.trigger_rule("tool-call",
+ p.literal(TOOL_CALL_START) +
p.python_style_tool_calls(inputs.tools, inputs.parallel_tool_calls) +
p.literal(TOOL_CALL_END)
)
@@ -1349,6 +1350,80 @@ static common_chat_params common_chat_params_init_lfm2(const common_chat_templat
{ COMMON_GRAMMAR_TRIGGER_TYPE_WORD, TOOL_CALL_START }
};
}
+ return data;
+}
+
+// LFM2.5 format: uses plain "List of tools: [...]" in system prompt, no wrapper tokens.
+// Tool calls are bare [name(arg="val")], though model may optionally emit <|tool_call_start|>.
+// - Reasoning: {reasoning} (optional)
+// - Content: text before a tool call (optional)
+// - Tool calls: Python-style, e.g. [function_name(arg1="value1", arg2="value2")]
+// Tool calls can appear multiple times (parallel tool calls supported)
+static common_chat_params common_chat_params_init_lfm2_5(const common_chat_template & tmpl,
+ const autoparser::generation_params & inputs) {
+ common_chat_params data;
+
+ data.prompt = common_chat_template_direct_apply(tmpl, inputs);
+ data.format = COMMON_CHAT_FORMAT_PEG_NATIVE;
+ data.supports_thinking = true;
+ data.preserved_tokens = {
+ "<|tool_call_start|>",
+ "<|tool_call_end|>",
+ "",
+ "",
+ };
+
+ auto has_tools = inputs.tools.is_array() && !inputs.tools.empty();
+ auto extract_reasoning = inputs.reasoning_format != COMMON_REASONING_FORMAT_NONE;
+ auto include_grammar = has_tools && inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_NONE;
+
+ const std::string THINK_START = "";
+ const std::string THINK_END = "";
+
+ data.thinking_start_tag = THINK_START;
+ data.thinking_end_tag = THINK_END;
+
+ auto parser = build_chat_peg_parser([&](common_chat_peg_builder & p) {
+ auto generation_prompt = p.prefix(inputs.generation_prompt, THINK_START);
+ auto end = p.end();
+
+ auto reasoning = p.eps();
+ if (extract_reasoning && inputs.enable_thinking) {
+ reasoning = p.optional(THINK_START + p.reasoning(p.until(THINK_END)) + THINK_END);
+ }
+
+ if (!has_tools || inputs.tool_choice == COMMON_CHAT_TOOL_CHOICE_NONE) {
+ return generation_prompt + reasoning + p.content(p.rest()) + end;
+ }
+
+ auto tool_calls = p.rule("tool-calls",
+ p.trigger_rule("tool-call",
+ p.python_style_tool_calls(inputs.tools, inputs.parallel_tool_calls)
+ )
+ );
+
+ auto content = p.content(p.until_one_of({"<|tool_call_start|>", "["}));
+ auto maybe_start = p.optional(p.literal("<|tool_call_start|>"));
+ return generation_prompt + reasoning + content + maybe_start + tool_calls + end;
+ });
+
+ data.parser = parser.save();
+
+ if (include_grammar) {
+ data.grammar_lazy = inputs.tool_choice == COMMON_CHAT_TOOL_CHOICE_AUTO;
+ data.grammar = build_grammar([&](const common_grammar_builder & builder) {
+ foreach_function(inputs.tools, [&](const json & tool) {
+ const auto & function = tool.at("function");
+ auto schema = function.at("parameters");
+ builder.resolve_refs(schema);
+ });
+ parser.build_grammar(builder, data.grammar_lazy);
+ });
+ foreach_function(inputs.tools, [&](const json & tool) {
+ const std::string name = tool.at("function").at("name");
+ data.grammar_triggers.push_back({ COMMON_GRAMMAR_TRIGGER_TYPE_WORD, "[" + name + "(" });
+ });
+ }
return data;
}
@@ -1530,14 +1605,21 @@ static std::optional try_specialized_template(
return common_chat_params_init_kimi_k2(tmpl, params);
}
- // LFM2 - uses <|tool_list_start|>/<|tool_list_end|> markers and <|tool_call_start|>[name(args)]<|tool_call_end|> format
- // Detection: template has "<|tool_list_start|>" and "<|tool_list_end|>" markers
+ // LFM2 format detection: template uses <|tool_list_start|>[...]<|tool_list_end|> around the tool list
+ // and <|tool_call_start|>[...]<|tool_call_end|> around each tool call
if (src.find("<|tool_list_start|>") != std::string::npos &&
src.find("<|tool_list_end|>") != std::string::npos) {
LOG_DBG("Using specialized template: LFM2\n");
return common_chat_params_init_lfm2(tmpl, params);
}
+ // LFM2.5 format detection: template uses plain "List of tools: [...]" with no special tokens
+ if (src.find("List of tools: [") != std::string::npos &&
+ src.find("<|tool_list_start|>") == std::string::npos) {
+ LOG_DBG("Using specialized template: LFM2.5\n");
+ return common_chat_params_init_lfm2_5(tmpl, params);
+ }
+
// GigaChatV3 format detection
if (src.find("<|role_sep|>") != std::string::npos &&
src.find("<|message_sep|>") != std::string::npos &&
diff --git a/models/templates/LFM2.5-Instruct.jinja b/models/templates/LFM2.5-Instruct.jinja
new file mode 100644
index 0000000000..7778756dd9
--- /dev/null
+++ b/models/templates/LFM2.5-Instruct.jinja
@@ -0,0 +1,45 @@
+{{- bos_token -}}
+{%- set keep_past_thinking = keep_past_thinking | default(false) -%}
+{%- set ns = namespace(system_prompt="") -%}
+{%- if messages[0]["role"] == "system" -%}
+ {%- set ns.system_prompt = messages[0]["content"] -%}
+ {%- set messages = messages[1:] -%}
+{%- endif -%}
+{%- if tools -%}
+ {%- set ns.system_prompt = ns.system_prompt + ("\n" if ns.system_prompt else "") + "List of tools: [" -%}
+ {%- for tool in tools -%}
+ {%- if tool is not string -%}
+ {%- set tool = tool | tojson -%}
+ {%- endif -%}
+ {%- set ns.system_prompt = ns.system_prompt + tool -%}
+ {%- if not loop.last -%}
+ {%- set ns.system_prompt = ns.system_prompt + ", " -%}
+ {%- endif -%}
+ {%- endfor -%}
+ {%- set ns.system_prompt = ns.system_prompt + "]" -%}
+{%- endif -%}
+{%- if ns.system_prompt -%}
+ {{- "<|im_start|>system\n" + ns.system_prompt + "<|im_end|>\n" -}}
+{%- endif -%}
+{%- set ns.last_assistant_index = -1 -%}
+{%- for message in messages -%}
+ {%- if message["role"] == "assistant" -%}
+ {%- set ns.last_assistant_index = loop.index0 -%}
+ {%- endif -%}
+{%- endfor -%}
+{%- for message in messages -%}
+ {{- "<|im_start|>" + message["role"] + "\n" -}}
+ {%- set content = message["content"] -%}
+ {%- if content is not string -%}
+ {%- set content = content | tojson -%}
+ {%- endif -%}
+ {%- if message["role"] == "assistant" and not keep_past_thinking and loop.index0 != ns.last_assistant_index -%}
+ {%- if "" in content -%}
+ {%- set content = content.split("")[-1] | trim -%}
+ {%- endif -%}
+ {%- endif -%}
+ {{- content + "<|im_end|>\n" -}}
+{%- endfor -%}
+{%- if add_generation_prompt -%}
+ {{- "<|im_start|>assistant\n" -}}
+{%- endif -%}
\ No newline at end of file
diff --git a/tests/test-chat.cpp b/tests/test-chat.cpp
index 1c4da68195..b66916687b 100644
--- a/tests/test-chat.cpp
+++ b/tests/test-chat.cpp
@@ -2712,6 +2712,67 @@ static void test_template_output_peg_parsers(bool detailed_debug) {
.run();
}
+ // LFM2.5 tests - uses plain "List of tools: [...]" and bare [name(args)] without wrapper tokens
+ {
+ auto tst = peg_tester("models/templates/LFM2.5-Instruct.jinja", detailed_debug);
+
+ // Basic content only
+ tst.test("Hello, world!\nWhat's up?").expect(message_assist).run();
+
+ // Single tool call without reasoning
+ tst.test("[special_function(arg1=1)]")
+ .tools({ special_function_tool })
+ .expect(message_assist_call)
+ .run();
+
+ // Tool call with string argument
+ tst.test("[get_time(city=\"XYZCITY\")]")
+ .tools({ get_time_tool })
+ .expect(message_with_tool_calls("get_time", "{\"city\":\"XYZCITY\"}"))
+ .run();
+
+ // Tool call with reasoning (enable_thinking=true)
+ tst.test("I'm\nthinking[special_function(arg1=1)]")
+ .enable_thinking(true)
+ .reasoning_format(COMMON_REASONING_FORMAT_AUTO)
+ .tools({ special_function_tool })
+ .expect(message_assist_call_thoughts)
+ .run();
+
+ // Multiple tool calls (parallel)
+ tst.test("[special_function(arg1=1), special_function_with_opt(arg1=1, arg2=2)]")
+ .parallel_tool_calls(true)
+ .tools({
+ special_function_tool, special_function_tool_with_optional_param
+ })
+ .expect_tool_calls({
+ { "special_function", R"({"arg1": 1})", {} },
+ { "special_function_with_opt", R"({"arg1": 1, "arg2": 2})", {} },
+ })
+ .run();
+
+ // Tool call with content before tool call
+ tst.test("Let me check the time.[get_time(city=\"Paris\")]")
+ .tools({ get_time_tool })
+ .expect(message_with_reasoning_content_and_multiple_tool_calls(
+ "", "Let me check the time.", { { "get_time", "{\"city\":\"Paris\"}" } }
+ ))
+ .run();
+
+ // Partial tool call (streaming)
+ tst.test("[special_function(arg1=")
+ .tools({ special_function_tool })
+ .is_partial(true)
+ .expect(simple_assist_msg("", "", "special_function", "{\"arg1\": "))
+ .run();
+
+ // Tool call with empty arguments
+ tst.test("[empty_args()]")
+ .tools({ empty_args_tool })
+ .expect(simple_assist_msg("", "", "empty_args", "{}"))
+ .run();
+ }
+
// Apertus-8B-Instruct tests - FUNC_NAME_AS_KEY format
// Format: <|tools_prefix|>[{"function_name": {...arguments...}}]<|tools_suffix|>
{