Minimax M2 chat template support

Author: pwilkin

common/chat.cpp

@@ -643,6 +643,7 @@ const char * common_chat_format_name(common_chat_format format) {
         case COMMON_CHAT_FORMAT_NEMOTRON_V2: return "Nemotron V2";
         case COMMON_CHAT_FORMAT_APERTUS: return "Apertus";
         case COMMON_CHAT_FORMAT_LFM2_WITH_JSON_TOOLS: return "LFM2 with JSON tools";
+        case COMMON_CHAT_FORMAT_MINIMAX_M2: return "MiniMax M2";
         default:
             throw std::runtime_error("Unknown chat format");
     }
@@ -2791,6 +2792,151 @@ static void common_chat_parse_seed_oss(common_chat_msg_parser & builder) {
     }
 }
 
+static common_chat_params common_chat_params_init_minimax_m2(
+    const common_chat_template         & tmpl,
+    templates_params                   & params,
+    const common_chat_templates_inputs & inputs)
+{
+    common_chat_params data;
+    data.prompt = apply(tmpl, params);
+    data.format = COMMON_CHAT_FORMAT_MINIMAX_M2;
+    if (string_ends_with(data.prompt, "<think>")) {
+        if (!inputs.enable_thinking) {
+            data.prompt += "</think>";
+        } else {
+            data.thinking_forced_open = true;
+        }
+    }
+
+    if (params.tools.is_array() && !params.tools.empty()) {
+        data.grammar_lazy = inputs.tool_choice != COMMON_CHAT_TOOL_CHOICE_REQUIRED;
+        data.grammar      = build_grammar([&](const common_grammar_builder & builder) {
+            std::vector<std::string> tool_rules;
+            foreach_function(params.tools, [&](const json & tool) {
+                const auto & function   = tool.at("function");
+                std::string  name       = function.at("name");
+                auto         parameters = function.at("parameters");
+                builder.resolve_refs(parameters);
+
+                // Create rule for Seed-OSS function call format
+                std::string param_rules;
+                if (parameters.contains("properties")) {
+                    for (const auto & [key, value] : parameters.at("properties").items()) {
+                        param_rules += "\"<parameter name=\\\"" + key + "\\\">\" " + builder.add_schema(name + "-arg-" + key, value) + " \"</parameter>\" space ";
+                    }
+                }
+                tool_rules.push_back(builder.add_rule(name + "-call",
+                                                      "\"<minimax:tool_call>\" space \"<invoke name=\\\"" + name + "\\\">\" space " +
+                                                          param_rules +
+                                                          " \"</invoke>\" space \"</minimax:tool_call>\""));
+            });
+
+            data.grammar_triggers.push_back({ COMMON_GRAMMAR_TRIGGER_TYPE_WORD, "<minimax:tool_call>" });
+
+            data.preserved_tokens = {
+                "<minimax:tool_call>", "</minimax:tool_call>", "<think>", "</think>",
+                "<function", "</function>", "<parameter", "</parameter>",
+            };
+
+            builder.add_rule("root", string_join(tool_rules, " | "));
+        });
+    }
+    return data;
+}
+
+static void common_chat_parse_minimax_m2(common_chat_msg_parser & builder) {
+    // Parse thinking tags first - this handles the main reasoning content
+    // Chat template doesn't seem to handle interleaving thinking, so we don't worry about it either
+    builder.try_parse_reasoning("<think>", "</think>");
+
+    if (!builder.syntax().parse_tool_calls) {
+        builder.add_content(builder.consume_rest());
+        return;
+    }
+
+    static const std::string tool_call_tag = "minimax:tool_call";
+    static const std::string function_tag = "invoke";
+    static const std::string parameter_tag = "parameter";
+
+    // Parse tool calls - similar to Seed OSS (pseudo-XML), but different syntax
+    static const common_regex tool_call_begin_regex("<" + tool_call_tag + ">");
+    static const common_regex tool_call_end_regex("</" + tool_call_tag + ">");
+    static const common_regex function_regex("<" + function_tag + " name=\"([^\"]+)\">");
+    static const common_regex param_regex("<" + parameter_tag + " name=\"([^\"]+)\">");
+
+    while (auto tool_res = builder.try_find_regex(tool_call_begin_regex)) {
+        builder.consume_spaces();  // Consume whitespace after <seed:tool_call>
+
+        // Look for function call inside tool call, ignore any content before it
+        if (auto func_res = builder.try_find_regex(function_regex, std::string::npos, false)) {
+            auto function_name = builder.str(func_res->groups[1]);
+
+            // Parse XML parameters <parameter name=\"name\">value</parameter>
+            json args = json::object();
+            // Parse all parameters
+            while (auto param_res = builder.try_find_regex(param_regex, std::string::npos, false)) {
+                // again, ignore noise around parameters
+                auto param_name = builder.str(param_res->groups[1]);
+                builder.move_to(param_res->groups[0].end);
+                builder.consume_spaces();  // Consume whitespace after parameter
+                auto savedPos = builder.pos();
+                if (auto param_parse = builder.try_find_literal("</" + parameter_tag + ">")) {
+                    auto param = param_parse->prelude;
+                    builder.move_to(savedPos);
+                    try {
+                        if (auto param_res = builder.try_consume_json()) {
+                            args[param_name] = param_res->json;
+                        } else {
+                            args[param_name] = param;
+                        }
+                    } catch (json::exception &) {
+                        args[param_name] = param;
+                    }
+                } else {
+                    throw common_chat_msg_partial_exception("Incomplete tool parameter");
+                }
+            }
+            // Look for closing function tag
+            auto end_func = builder.try_find_literal("</" + function_tag + ">");
+            if (end_func) {
+                builder.move_to(end_func->groups[0].end);
+                builder.consume_spaces();  // Consume whitespace after </function>
+
+                // Add the tool call with parsed arguments, but only if we REALLY got the literal
+                auto eaten_fragment = builder.input().substr(end_func->groups[0].begin, end_func->groups[0].end);
+                auto funlen = std::string("</" + function_tag + ">").length();
+                if (eaten_fragment.length() >= funlen && eaten_fragment.substr(0, funlen) == std::string("</" + function_tag + ">")) {
+                    if (!builder.add_tool_call(function_name, "", args.dump())) {
+                        throw common_chat_msg_partial_exception("Incomplete tool call");
+                    }
+                } else {
+                    throw common_chat_msg_partial_exception("Incomplete tool call");
+                }
+            } else {
+                throw common_chat_msg_partial_exception("Incomplete tool call");
+            }
+            // Look for closing tool call tag
+            if (auto end_tool = builder.try_find_regex(tool_call_end_regex, std::string::npos, false)) {
+                builder.move_to(end_tool->groups[0].end);
+                builder.consume_spaces();  // Consume trailing whitespace after tool call
+            } else {
+                throw common_chat_msg_partial_exception("Incomplete tool call");
+            }
+        } else {
+            // No function found - don't consume content here, let it be handled at the end
+            break;
+        }
+    }
+
+    // Consume any remaining whitespace after all tool call processing
+    builder.consume_spaces();
+    auto remaining = builder.consume_rest();
+    // If there's any non-whitespace content remaining, add it as content
+    if (!string_strip(remaining).empty()) {
+        builder.add_content(remaining);
+    }
+}
+
 static common_chat_params common_chat_params_init_without_tools(const common_chat_template & tmpl, const struct templates_params & inputs) {
     common_chat_params data;
     data.prompt = apply(tmpl, inputs);
@@ -2942,6 +3088,11 @@ static common_chat_params common_chat_templates_apply_jinja(
         return common_chat_params_init_seed_oss(tmpl, params, inputs);
     }
 
+    // MiniMax M2
+    if (src.find("<minimax:tool_call>") != std::string::npos) {
+        return common_chat_params_init_minimax_m2(tmpl, params, inputs);
+    }
+
     // Nemotron v2
     if (src.find("<SPECIAL_10>") != std::string::npos) {
         return common_chat_params_init_nemotron_v2(tmpl, params);
@@ -3139,6 +3290,9 @@ static void common_chat_parse(common_chat_msg_parser & builder) {
         case COMMON_CHAT_FORMAT_LFM2_WITH_JSON_TOOLS:
             common_chat_parse_lfm2(builder);
             break;
+        case COMMON_CHAT_FORMAT_MINIMAX_M2:
+            common_chat_parse_minimax_m2(builder);
+            break;
         default:
             throw std::runtime_error(std::string("Unsupported format: ") + common_chat_format_name(builder.syntax().format));
     }

common/chat.h

@@ -117,6 +117,7 @@ enum common_chat_format {
     COMMON_CHAT_FORMAT_NEMOTRON_V2,
     COMMON_CHAT_FORMAT_APERTUS,
     COMMON_CHAT_FORMAT_LFM2_WITH_JSON_TOOLS,
+    COMMON_CHAT_FORMAT_MINIMAX_M2,
 
     COMMON_CHAT_FORMAT_COUNT, // Not a format, just the # formats
 };

models/templates/MiniMax-M2.jinja

@@ -0,0 +1,153 @@
+{# ----------‑‑‑ special token variables ‑‑‑---------- #}
+{%- set toolcall_begin_token   = '<minimax:tool_call>'         -%}
+{%- set toolcall_end_token     = '</minimax:tool_call>'        -%}
+{#- Tool Rendering Functions ============================================== -#}
+{%- macro render_tool_namespace(namespace_name, tool_list) -%}
+{%- for tool in tool_list -%}
+<tool>{{ tool.function | tojson() }}</tool>
+{% endfor -%}
+{%- endmacro -%}
+{%- macro visible_text(content) -%}
+    {%- if content is string -%}
+        {{ content }}
+    {%- elif content is iterable and content is not mapping -%}
+        {%- for item in content -%}
+            {%- if item is mapping and item.type == 'text' -%}
+                {{- item.text }}
+            {%- elif item is string -%}
+                {{- item }}
+            {%- endif -%}
+        {%- endfor -%}
+    {%- else -%}
+        {{- content }}
+    {%- endif -%}
+{%- endmacro -%}
+{#- System Message Construction ============================================ -#}
+{%- macro build_system_message(system_message) -%}
+    {%- if system_message and system_message.content -%}
+        {{- visible_text(system_message.content) }}
+    {%- else -%}
+        {%- if model_identity is not defined -%}
+            {%- set model_identity = "You are a helpful assistant." -%}
+        {%- endif -%}
+        {{- model_identity }}
+    {%- endif -%}
+    
+    {#- Handle current_date -#}
+    {%- if system_message and system_message.current_date -%}
+        {{- '\n' ~ 'Current date: ' + system_message.current_date }}
+    {%- endif -%}
+    {#- Handle current_location -#}
+    {%- if system_message and system_message.current_location -%}
+        {{- '\n' ~ 'Current location: ' + system_message.current_location }}
+    {%- endif -%}
+{%- endmacro -%}
+{#- Main Template Logic ================================================= -#}
+{#- Extract system message (only first message if it's system) -#}
+{%- set system_message = none -%}
+{%- set conversation_messages = messages -%}
+{%- if messages and messages[0].role == "system" -%}
+    {%- set system_message = messages[0] -%}
+    {%- set conversation_messages = messages[1:] -%}
+{%- endif -%}
+{#- Get the last user message turn, for interleved thinking -#}
+{%- set ns = namespace(last_user_index=-1) %}
+{% for m in conversation_messages %}
+    {%- if m.role == 'user' %}
+        {% set ns.last_user_index = loop.index0 -%}
+    {%- endif %}
+{%- endfor %}
+{#- Render system message -#}
+{{- ']~!b[' ~ ']~b]system' ~ '\n' }}
+{{- build_system_message(system_message) }}
+{#- Render tools if available -#}
+{%- if tools -%}
+    {{- '\n\n' ~ '# Tools' ~ '\n' ~ 'You may call one or more tools to assist with the user query.\nHere are the tools available in JSONSchema format:' ~ '\n' }}
+    {{- '\n' ~ '<tools>' ~ '\n' }}
+    {{- render_tool_namespace("functions", tools) }}
+    {{- '</tools>' ~ '\n\n' }}
+{{- 'When making tool calls, use XML format to invoke tools and pass parameters:' ~ '\n' }}
+{{- '\n' ~ toolcall_begin_token }}
+<invoke name="tool-name-1">
+<parameter name="param-key-1">param-value-1</parameter>
+<parameter name="param-key-2">param-value-2</parameter>
+...
+</invoke>
+{{- '\n' ~ toolcall_end_token }}
+{%- endif -%}
+{{- '[e~[\n' }}
+{#- Render messages -#}
+{%- set last_tool_call = namespace(name=none) -%}
+{%- for message in conversation_messages -%}
+    {%- if message.role == 'assistant' -%}
+        {#- Only render reasoning_content if no user message follows -#}
+        {{- ']~b]ai' ~ '\n' }}
+        {%- set reasoning_content = '' %}
+        {%- set content = visible_text(message.content) %}
+        {%- if message.reasoning_content is string %}
+            {%- set reasoning_content = message.reasoning_content %}
+        {%- else %}
+            {%- if '</think>' in content %}
+                {%- set reasoning_content = content.split('</think>')[0].strip('\n').split('<think>')[-1].strip('\n') %}
+                {%- set content = content.split('</think>')[-1].strip('\n') %}
+            {%- endif %}
+        {%- endif %}
+        {%- if reasoning_content and loop.index0 > ns.last_user_index -%}
+            {{- '<think>' ~ '\n' ~ reasoning_content ~ '\n' ~ '</think>' ~ '\n\n' }}
+        {%- endif -%}
+        {%- if content -%}
+            {{- content }}
+        {%- endif -%}
+        {%- if message.tool_calls -%}
+            {{- toolcall_begin_token ~ '\n' }}
+            {%- for tool_call in message.tool_calls -%}
+                {%- if tool_call.function %}
+                    {%- set tool_call = tool_call.function %}
+                {%- endif %}
+                {{- '<invoke name="' + tool_call.name + '">' }}
+                {% set _args = tool_call.arguments %}
+                {%- for k, v in _args | items %}
+                {{- '<parameter name="' + k + '">' }}
+                {{- v | tojson if v is not string else v }}
+                {{- '</parameter>' }}
+                {% endfor %}
+                {{- '</invoke>' ~ '\n' }}
+            {%- endfor -%}
+            {{- toolcall_end_token}}
+            {%- set last_tool_call.name = message.tool_calls[-1].name -%}
+        {%- else -%}
+            {%- set last_tool_call.name = none -%}
+        {%- endif -%}
+        {{- '[e~[' ~ '\n' }}
+    {%- elif message.role == 'tool' -%}
+    {%- if last_tool_call.name is none -%}
+        {{- raise_exception("Message has tool role, but there was no previous assistant message with a tool call!") }}
+    {%- endif -%}
+    {%- if loop.first or (conversation_messages[loop.index0 - 1].role != 'tool') -%}
+        {{- ']~b]tool' }}
+    {%- endif -%}
+    {%- if message.content is string -%}
+        {{- '\n<response>' }}
+        {{- message.content }}
+        {{- '</response>' }}
+    {%- else -%}
+        {%- for tr in message.content -%}
+            {{- '\n<response>' }}
+            {{- tr.output if tr.output is defined else (tr.text if tr.type == 'text' and tr.text is defined else tr) }}
+            {{- '\n</response>' }}
+        {%- endfor -%}
+    {%- endif -%}
+    {%- if loop.last or (conversation_messages[loop.index0 + 1].role != 'tool') -%}
+        {{- '[e~[\n' -}}
+    {%- endif -%}
+        
+    {%- elif message.role == 'user' -%}
+        {{- ']~b]user' ~ '\n' }}
+        {{- visible_text(message.content) }}
+        {{- '[e~[' ~ '\n' }}
+    {%- endif -%}
+{%- endfor -%}
+{#- Generation prompt -#}
+{%- if add_generation_prompt -%}
+{{- ']~b]ai' ~ '\n' ~ '<think>' ~ '\n' }}
+{%- endif -%}