{#- Default system message if no system prompt is passed. #}
{%- set default_system_message = 'You are OpenMed, a PII (Personally Identifiable Information) extraction assistant.\nExtract all PII entities from the given text and return them as a JSON array.\nEach entity should have \'text\' (the extracted value) and \'label\' (the PII type).\nIf no PII is found, return an empty array [].\n\nExamples:\n\nInput: "Contact John Smith at john.smith@email.com or call 555-0123."\nOutput: [{"text": "John Smith", "label": "first_name"}, {"text": "john.smith@email.com", "label": "email"}, {"text": "555-0123", "label": "phone_number"}]\n\nInput: "The meeting is scheduled for tomorrow at 3pm."\nOutput: []\n\nInput: "Send the package to 456 Oak Ave, Springfield, IL 62704."\nOutput: [{"text": "456 Oak Ave", "label": "street_address"}, {"text": "Springfield", "label": "city"}, {"text": "IL", "label": "state"}, {"text": "62704", "label": "zip_code"}]' %}

{#- Begin of sequence token. #}
{{- bos_token }}

{#- Handle system prompt if it exists. #}
{%- if messages[0]['role'] == 'system' %}
    {{- '[SYSTEM_PROMPT]' -}}
    {%- if messages[0]['content'] is string %}
        {{- messages[0]['content'] -}}
    {%- else %}
        {%- for block in messages[0]['content'] %}
            {%- if block['type'] == 'text' %}
                {{- block['text'] }}
            {%- else %}
                {{- raise_exception('Only text chunks are supported in system message contents.') }}
            {%- endif %}
        {%- endfor %}
    {%- endif %}
    {{- '[/SYSTEM_PROMPT]' -}}
    {%- set loop_messages = messages[1:] %}
{%- else %}
    {%- set loop_messages = messages %}
    {%- if default_system_message != '' %}
        {{- '[SYSTEM_PROMPT]' + default_system_message + '[/SYSTEM_PROMPT]' }}
    {%- endif %}
{%- endif %}

{#- Checks for alternating user/assistant messages. #}
{%- set ns = namespace(index=0) %}
{%- for message in loop_messages %}
    {%- if (message['role'] == 'user') != (ns.index % 2 == 0) %}
        {{- raise_exception('Conversation roles must alternate user/assistant after the optional system message.') }}
    {%- endif %}
    {%- set ns.index = ns.index + 1 %}
{%- endfor %}

{#- Handle conversation messages. #}
{%- for message in loop_messages %}

    {%- if message['role'] == 'user' %}
        {%- if message['content'] is string %}
            {{- '[INST]' + message['content'] + '[/INST]' }}
        {%- elif message['content'] | length > 0 %}
            {{- '[INST]' }}
            {%- for block in message['content'] %}
                {%- if block['type'] == 'text' %}
                    {{- block['text'] }}
                {%- elif block['type'] in ['image', 'image_url'] %}
                    {{- '[IMG]' }}
                {%- else %}
                    {{- raise_exception('Only text, image and image_url chunks are supported in user message content.') }}
                {%- endif %}
            {%- endfor %}
            {{- '[/INST]' }}
        {%- else %}
            {{- raise_exception('User message must have a string or a list of chunks in content') }}
        {%- endif %}

    {%- elif message['role'] == 'assistant' %}
        {%- if message['content'] is none or message['content'] == '' or message['content']|length == 0 %}
            {{- raise_exception('Assistant message must have content.') }}
        {%- endif %}
        {%- if message['content'] is string %}
            {{- message['content'] }}
        {%- elif message['content'] | length > 0 %}
            {%- for block in message['content'] %}
                {%- if block['type'] == 'text' %}
                    {{- block['text'] }}
                {%- else %}
                    {{- raise_exception('Only text chunks are supported in assistant message contents.') }}
                {%- endif %}
            {%- endfor %}
        {%- endif %}
        {{- eos_token }}

    {%- else %}
        {{- raise_exception('Only user and assistant roles are supported, got ' + message['role'] + '.') }}
    {%- endif %}
{%- endfor %}

{#- Generation prompt intentionally left empty.
    The best full-eval runtime keeps the system prompt but does not prefill a
    markdown JSON fence; the model emits the JSON array itself. #}