v0.4.13, GUI: Gemma 4 26B A4B it compressed: unable to use tools

[SINAPSA-IC]

Windows 11
LM Studio 0.4.13
GUI
LLM: Gemma 4 26B A4B it compressed (~9GB filesize)
MoE - Active Experts: 16
Plugins active:

• js-code-sandbox (comes with the program)
• beledarian's LM Studio Toolbox (https://github.com/Beledarian/Beledarians_LM_Studio_Toolbox)

Prompt-ing while any of ^those plugins (that is, not both of them) was active.

Outcome: Error message:

"Failed to generate AI response
Error rendering prompt with jinja template: "Cannot call something that is not a function: got UndefinedValue".

This is usually an issue with the model's prompt template. If you are using a popular model, you can try to search the model under lmstudio-community, which will have fixed prompt templates. If you cannot find one, you are welcome to post this issue to our discord or issue tracker on GitHub. Alternatively, if you know how to write jinja templates, you can override the prompt template in My Models > model settings > Prompt Template."

Probable cause:
(this version of) Gemma 4 (26B, A4B, it, compressed) is not adjusted for tool use within LM Studio 0.4.13.

[sterlp]

Same issue with gemma-4-26b-a4b-it-claude-opus-distill-v2 or gemma4-26b-a4b-uncensored-hauhaucs-balanced -- it works with llama.cpp. Means it has something todo with LM Studio.

Model itself works for me -- I tested these models with Hermes first:

⚠️  API call failed (attempt 1/3): APIError
   🔌 Provider: lmstudio  Model: gemma-4-26b-a4b-it-claude-opus-distill-v2
   🌐 Endpoint: http://127.0.0.1:1234/v1
   📝 Error: Error rendering prompt with jinja template: "Cannot call something that is not a function: got UndefinedValue".

This is usually an issue with the model's prompt template. If you are using a popular model, you can try to search the model under lmstudio-community, which will have fixed prompt templat
   ⏱️  Elapsed: 0.40s  Context: 2 msgs, ~4,375 tokens
⏳ Retrying in 2.9s (attempt 1/3)...
⚠️  API call failed (attempt 2/3): APIError
   🔌 Provider: lmstudio  Model: gemma-4-26b-a4b-it-claude-opus-distill-v2
   🌐 Endpoint: http://127.0.0.1:1234/v1
   📝 Error: Error rendering prompt with jinja template: "Cannot call something that is not a function: got UndefinedValue".

---

Here the template I get in LM Studio 0.4.15:

{%- macro format_parameters(properties, required, filter_keys=false) -%}
    {%- set standard_keys = ['description', 'type', 'properties', 'required', 'nullable'] -%}
    {%- set ns = namespace(found_first=false) -%}
    {%- for key, value in properties | dictsort -%}
        {%- set add_comma = false -%}
        {%- if not filter_keys or key not in standard_keys -%}
            {%- if ns.found_first %},{% endif -%}
            {%- set ns.found_first = true -%}
            {{ key }}:{
            {%- if value['description'] -%}
                description:<|"|>{{ value['description'] }}<|"|>
                {%- set add_comma = true -%}
            {%- endif -%}
            {%- if value['type'] and ('string' in value['type'] or 'STRING' in value['type']) -%}
                {%- if value['enum'] -%}
                    {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
                    enum:{{ format_argument(value['enum']) }}
                {%- endif -%}
            {%- elif value['type'] and ('array' in value['type'] or 'ARRAY' in value['type']) -%}
                {%- if value['items'] is mapping and value['items'] -%}
                    {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
                    items:{
                    {%- set ns_items = namespace(found_first=false) -%}
                    {%- for item_key, item_value in value['items'] | dictsort -%}
                        {%- if item_value is not none -%}
                            {%- if ns_items.found_first %},{% endif -%}
                            {%- set ns_items.found_first = true -%}
                            {%- if item_key == 'properties' -%}
                                properties:{
                                {%- if item_value is mapping -%}
                                    {{- format_parameters(item_value, value['items']['required'] | default([])) -}}
                                {%- endif -%}
                                }
                            {%- elif item_key == 'required' -%}
                                required:[
                                {%- for req_item in item_value -%}
                                    <|"|>{{- req_item -}}<|"|>
                                    {%- if not loop.last %},{% endif -%}
                                {%- endfor -%}
                                ]
                            {%- elif item_key == 'type' -%}
                                type:{{ format_type_argument(item_value) }}
                            {%- else -%}
                                {{ item_key }}:{{ format_argument(item_value) }}
                            {%- endif -%}
                        {%- endif -%}
                    {%- endfor -%}
                    }
                {%- endif -%}
            {%- endif -%}
            {%- if value['nullable'] %}
                {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
                nullable:true
            {%- endif -%}
            {%- if value['type'] and ('object' in value['type'] or 'OBJECT' in value['type']) -%}
                {%- if value['properties'] is defined and value['properties'] is mapping -%}
                    {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
                    properties:{
                    {{- format_parameters(value['properties'], value['required'] | default([])) -}}
                    }
                {%- elif value is mapping -%}
                    {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
                    properties:{
                    {{- format_parameters(value, value['required'] | default([]), filter_keys=true) -}}
                    }
                {%- endif -%}
                {%- if value['required'] -%}
                    {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
                    required:[
                    {%- for item in value['required'] | default([]) -%}
                        <|"|>{{- item -}}<|"|>
                        {%- if not loop.last %},{% endif -%}
                    {%- endfor -%}
                    ]
                {%- endif -%}
            {%- endif -%}
            {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
            type:{{ format_type_argument(value['type']) }}}
        {%- endif -%}
    {%- endfor -%}
{%- endmacro -%}
{%- macro format_function_declaration(tool_data) -%}
    declaration:{{- tool_data['function']['name'] -}}{description:<|"|>{{- tool_data['function']['description'] -}}<|"|>
    {%- set params = tool_data['function']['parameters'] -%}
    {%- if params -%}
        ,parameters:{
        {%- if params['properties'] -%}
            properties:{ {{- format_parameters(params['properties'], params['required']) -}} },
        {%- endif -%}
        {%- if params['required'] -%}
            required:[
            {%- for item in params['required'] -%}
                <|"|>{{- item -}}<|"|>
                {{- ',' if not loop.last -}}
            {%- endfor -%}
            ],
        {%- endif -%}
        {%- if params['type'] -%}
            type:{{- format_type_argument(params['type']) -}}}
        {%- endif -%}
    {%- endif -%}
    {%- if 'response' in tool_data['function'] -%}
        {%- set response_declaration = tool_data['function']['response'] -%}
        ,response:{
        {%- if response_declaration['description'] -%}
            description:<|"|>{{- response_declaration['description'] -}}<|"|>,
        {%- endif -%}
        {%- if response_declaration['type'] and ('object' in response_declaration['type'] or 'OBJECT' in response_declaration['type']) -%}
            type:{{- format_type_argument(response_declaration['type']) -}}}
        {%- endif -%}
    {%- endif -%}
    }
{%- endmacro -%}
{%- macro format_argument(argument, escape_keys=True) -%}
    {%- if argument is string -%}
        {{- '<|"|>' + argument + '<|"|>' -}}
    {%- elif argument is boolean -%}
        {{- 'true' if argument else 'false' -}}
    {%- elif argument is mapping -%}
        {{- '{' -}}
        {%- set ns = namespace(found_first=false) -%}
        {%- for key, value in argument | dictsort -%}
            {%- if ns.found_first %},{% endif -%}
            {%- set ns.found_first = true -%}
            {%- if escape_keys -%}
                {{- '<|"|>' + key + '<|"|>' -}}
            {%- else -%}
                {{- key -}}
            {%- endif -%}
            :{{- format_argument(value, escape_keys=escape_keys) -}}
        {%- endfor -%}
        {{- '}' -}}
    {%- elif argument is iterable -%}
        {{- '[' -}}
        {%- for item in argument -%}
            {{- format_argument(item, escape_keys=escape_keys) -}}
            {%- if not loop.last %},{% endif -%}
        {%- endfor -%}
        {{- ']' -}}
    {%- else -%}
        {{- argument -}}
    {%- endif -%}
{%- endmacro -%}
{%- macro strip_thinking(text) -%}
    {%- set ns = namespace(result='') -%}
    {%- for part in text.split('<channel|>') -%}
        {%- if '<|channel>' in part -%}
            {%- set ns.result = ns.result + part.split('<|channel>')[0] -%}
        {%- else -%}
            {%- set ns.result = ns.result + part -%}
        {%- endif -%}
    {%- endfor -%}
    {{- ns.result | trim -}}
{%- endmacro -%}

{%- macro format_tool_response_block(tool_name, response) -%}
    {{- '<|tool_response>' -}}
    {%- if response is mapping -%}
        {{- 'response:' + tool_name + '{' -}}
        {%- for key, value in response | dictsort -%}
            {{- key -}}:{{- format_argument(value, escape_keys=False) -}}
            {%- if not loop.last %},{% endif -%}
        {%- endfor -%}
        {{- '}' -}}
    {%- else -%}
        {{- 'response:' + tool_name + '{value:' + format_argument(response, escape_keys=False) + '}' -}}
    {%- endif -%}
    {{- '<tool_response|>' -}}
{%- endmacro -%}

{%- set ns = namespace(prev_message_type=None) -%}
{%- set loop_messages = messages -%}
{{- bos_token -}}
{#- Handle System/Tool Definitions Block -#}
{%- if (enable_thinking is defined and enable_thinking) or tools or messages[0]['role'] in ['system', 'developer'] -%}
    {{- '<|turn>system\n' -}}
    {#- Inject Thinking token at the very top of the FIRST system turn -#}
    {%- if enable_thinking is defined and enable_thinking -%}
        {{- '<|think|>\n' -}}
        {%- set ns.prev_message_type = 'think' -%}
    {%- endif -%}
    {%- if messages[0]['role'] in ['system', 'developer'] -%}
        {%- if messages[0]['content'] is string -%}
            {{- messages[0]['content'] | trim -}}
        {%- elif messages[0]['content'] is iterable -%}
            {%- for item in messages[0]['content'] -%}
                {{- item['text'] | trim + ' '-}}
            {%- endfor -%}
        {%- endif -%}
        {%- set loop_messages = messages[1:] -%}
    {%- endif -%}
    {%- if tools -%}
        {%- for tool in tools %}
            {{- '<|tool>' -}}
            {{- format_function_declaration(tool) | trim -}}
            {{- '<tool|>' -}}
        {%- endfor %}
        {%- set ns.prev_message_type = 'tool' -%}
    {%- endif -%}
    {{- '<turn|>\n' -}}
{%- endif %}

{#- Pre-scan: find last user message index for reasoning guard -#}
{%- set ns_turn = namespace(last_user_idx=-1) -%}
{%- for i in range(loop_messages | length) -%}
    {%- if loop_messages[i]['role'] == 'user' -%}
        {%- set ns_turn.last_user_idx = i -%}
    {%- endif -%}
{%- endfor -%}

{#- Loop through messages -#}
{%- for message in loop_messages -%}
    {%- if message['role'] != 'tool' -%}
    {%- set ns.prev_message_type = None -%}
    {%- set role = 'model' if message['role'] == 'assistant' else message['role'] -%}
    {#- Detect continuation: suppress duplicate <|turn>model when previous non-tool message was also assistant -#}
    {%- set prev_nt = namespace(role=None, found=false) -%}
    {%- if loop.index0 > 0 -%}
        {%- for j in range(loop.index0 - 1, -1, -1) -%}
            {%- if not prev_nt.found -%}
                {%- if loop_messages[j]['role'] != 'tool' -%}
                    {%- set prev_nt.role = loop_messages[j]['role'] -%}
                    {%- set prev_nt.found = true -%}
                {%- endif -%}
            {%- endif -%}
        {%- endfor -%}
    {%- endif -%}
    {%- set continue_same_model_turn = (role == 'model' and prev_nt.role == 'assistant') -%}
    {%- if not continue_same_model_turn -%}
        {{- '<|turn>' + role + '\n' }}
    {%- endif -%}

    {#- Render reasoning/reasoning_content as thinking channel -#}
    {%- set thinking_text = message.get('reasoning') or message.get('reasoning_content') -%}
    {%- if thinking_text and loop.index0 > ns_turn.last_user_idx and message.get('tool_calls') -%}
        {{- '<|channel>thought\n' + thinking_text + '\n<channel|>' -}}
    {%- endif -%}

            {%- if message['tool_calls'] -%}
                {%- for tool_call in message['tool_calls'] -%}
                    {%- set function = tool_call['function'] -%}
                    {{- '<|tool_call>call:' + function['name'] + '{' -}}
                    {%- if function['arguments'] is mapping -%}
                        {%- set ns_args = namespace(found_first=false) -%}
                        {%- for key, value in function['arguments'] | dictsort -%}
                            {%- if ns_args.found_first %},{% endif -%}
                            {%- set ns_args.found_first = true -%}
                            {{- key -}}:{{- format_argument(value, escape_keys=False) -}}
                        {%- endfor -%}
                    {%- elif function['arguments'] is string -%}
                        {{- function['arguments'] -}}
                    {%- endif -%}
                    {{- '}<tool_call|>' -}}
                {%- endfor -%}
                {%- set ns.prev_message_type = 'tool_call' -%}
            {%- endif -%}

            {%- set ns_tr_out = namespace(flag=false) -%}
            {%- if message.get('tool_responses') -%}
                {#- Legacy: tool_responses embedded on the assistant message (Google/Gemma native) -#}
                {%- for tool_response in message['tool_responses'] -%}
                    {{- format_tool_response_block(tool_response['name'] | default('unknown'), tool_response['response']) -}}
                    {%- set ns_tr_out.flag = true -%}
                    {%- set ns.prev_message_type = 'tool_response' -%}
                {%- endfor -%}
            {%- elif message.get('tool_calls') -%}
                {#- OpenAI Chat Completions: forward-scan consecutive role:tool messages -#}
                {%- set ns_tool_scan = namespace(stopped=false) -%}
                {%- for k in range(loop.index0 + 1, loop_messages | length) -%}
                    {%- if ns_tool_scan.stopped -%}
                    {%- elif loop_messages[k]['role'] != 'tool' -%}
                        {%- set ns_tool_scan.stopped = true -%}
                    {%- else -%}
                        {%- set follow = loop_messages[k] -%}
                        {#- Resolve tool_call_id to function name -#}
                        {%- set ns_tname = namespace(name=follow.get('name') | default('unknown')) -%}
                        {%- for tc in message['tool_calls'] -%}
                            {%- if tc.get('id') == follow.get('tool_call_id') -%}
                                {%- set ns_tname.name = tc['function']['name'] -%}
                            {%- endif -%}
                        {%- endfor -%}
                        {#- Handle content as string or content-parts array -#}
                        {%- set tool_body = follow.get('content') -%}
                        {%- if tool_body is string -%}
                            {{- format_tool_response_block(ns_tname.name, tool_body) -}}
                        {%- elif tool_body is iterable and tool_body is not string -%}
                            {%- set ns_txt = namespace(s='') -%}
                            {%- for part in tool_body -%}
                                {%- if part.get('type') == 'text' -%}
                                    {%- set ns_txt.s = ns_txt.s + (part.get('text') | default('')) -%}
                                {%- endif -%}
                            {%- endfor -%}
                            {{- format_tool_response_block(ns_tname.name, ns_txt.s) -}}
                        {%- else -%}
                            {{- format_tool_response_block(ns_tname.name, tool_body) -}}
                        {%- endif -%}
                        {%- set ns_tr_out.flag = true -%}
                        {%- set ns.prev_message_type = 'tool_response' -%}
                    {%- endif -%}
                {%- endfor -%}
            {%- endif -%}

            {%- set captured_content -%}
            {%- if message['content'] is string -%}
                {%- if role == 'model' -%}
                    {{- strip_thinking(message['content']) -}}
                {%- else -%}
                    {{- message['content'] | trim -}}
                {%- endif -%}
            {%- elif message['content'] is iterable -%}
                {%- for item in message['content'] -%}
                    {%- if item['type'] == 'text' -%}
                        {%- if role == 'model' -%}
                            {{- strip_thinking(item['text']) -}}
                        {%- else -%}
                            {{- item['text'] | trim -}}
                        {%- endif -%}
                    {%- elif item['type'] == 'image' -%}
                        {{- '<|image|>' -}}
                        {%- set ns.prev_message_type = 'image' -%}
                    {%- elif item['type'] == 'audio' -%}
                        {{- '<|audio|>' -}}
                        {%- set ns.prev_message_type = 'audio' -%}
                    {%- elif item['type'] == 'video' -%}
                        {{- '<|video|>' -}}
                        {%- set ns.prev_message_type = 'video' -%}
                    {%- endif -%}
                {%- endfor -%}
            {%- endif -%}
            {%- endset -%}

            {{- captured_content -}}
            {%- set has_content = captured_content | trim | length > 0 -%}

        {%- if ns.prev_message_type == 'tool_call' and not ns_tr_out.flag -%}
            {{- '<|tool_response>' -}}
        {%- elif not (ns_tr_out.flag and not has_content) -%}
            {{- '<turn|>\n' -}}
        {%- endif -%}
    {%- endif -%}
{%- endfor -%}

{%- if add_generation_prompt -%}
    {%- if ns.prev_message_type != 'tool_response' and ns.prev_message_type != 'tool_call' -%}
        {{- '<|turn>model\n' -}}
        {%- if not enable_thinking | default(false) -%}
            {{- '<|channel>thought\n<channel|>' -}}
        {%- endif -%}
    {%- endif -%}
{%- endif -%}

Thinking is broken a bit to using the model directly:

[sterlp]

where is a warning in llama.cpp:

0.00.927.753 I common_init_result: (for bugs during this step try to reproduce them with -fit off, or provide --verbose logs if the bug only occurs with -fit on)
0.07.312.552 W load: control-looking token:     50 '<|tool_response>' was not control-type; this is probably a bug in the model. its type will be overridden
0.07.312.802 W load: control-looking token:    212 '</s>' was not control-type; this is probably a bug in the model. its type will be overridden
0.07.336.091 W load: special_eog_ids contains '<|tool_response>', removing '</s>' token from EOG list
0.20.227.154 W llama_context: n_ctx_seq (120064) < n_ctx_train (262144) -- the full capacity of the model will not be utilized
0.20.227.971 W llama_kv_cache_iswa: using full-size SWA cache (ref: https://github.com/ggml-org/llama.cpp/pull/13194#issuecomment-2868343055)
0.21.735.502 I common_init_from_params: warming up the model with an empty run - please wait ... (--no-warmup to disable)
0.26.486.015 I srv    load_model: loaded multimodal model, 'C:/Users/Paul/.lmstudio/models/TeichAI/gemma-4-26B-A4B-it-Claude-Opus-Distill-v2-GGUF/mmproj-F16.gguf'
0.26.486.021 W srv    load_model: cache_reuse is not supported by multimodal, it will be disabled`

[FakeUser2121]

Root cause identified: the Gemma 4 chat template calls format_type_argument but that macro is never defined in the bundled template. Adding this one macro at the top fixes it:

{%- macro format_type_argument(type_arg) -%}
    {{- type_arg if type_arg is string else format_argument(type_arg) -}}
{%- endmacro -%}

Confirmed working on LM Studio 0.4.16 with gemma-4-12b-it-ud via OpenCode.

[djmtype]

Root cause identified: the Gemma 4 chat template calls format_type_argument but that macro is never defined in the bundled template. Adding this one macro at the top fixes it:

{%- macro format_type_argument(type_arg) -%}
    {{- type_arg if type_arg is string else format_argument(type_arg) -}}
{%- endmacro -%}

Confirmed working on LM Studio 0.4.16 with gemma-4-12b-it-ud via OpenCode.

Ironically, Gemini 3.5 Flash could not even solve this question right when using LM Studio lmstudio-community/gemma-4-12b-it-mlx with Zed.

[AnuAnu22]

My gemini did solve it.