gemma 4 chat template that works with opencode - download the .jinja file and tell vllm to use it via `--chat-template chat_template_gemma_large_fixed.jinja`

Instructions for using a specific chat template file (`chat_template_gemma_large_fixed.jinja`) with the vLLM inference engine to enable compatibility with the Gemma 4 model and OpenCode. It directs users to download the `.jinja` file and apply it by adding the `--chat-template` flag followed by the filename when running vLLM. The body of the article contains the actual Jinja template code, which defines macros for formatting function parameters and their properties.

Created April 17, 2026 00:24 - - Save bbrowning/c584eb2dbd79e4cc9ecedf92eee2d135 to your computer and use it in GitHub Desktop. gemma 4 chat template that works with opencode - download the .jinja file and tell vllm to use it via --chat-template chat template gemma large fixed.jinja This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters https://github.co/hiddenchars | {%- macro format parameters properties, required -%} | | | {%- 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 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' | upper == 'STRING' -%} | | | {%- if value 'enum' -%} | | | {%- if add comma %},{%- else -%} {%- set add comma = true -%} {% endif -%} | | | enum:{{ format argument value 'enum' }} | | | {%- endif -%} | | | {%- elif value 'type' | upper == 'ARRAY' -%} | | | {%- 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' -%} | | | {%- if item value is string -%} | | | type:{{ format argument item value | upper }} | | | {%- else -%} | | | type:{{ format argument item value | map 'upper' | list }} | | | {%- endif -%} | | | {%- 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' | upper == 'OBJECT' -%} | | | {%- 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 -}} | | | } | | | {%- 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:<|"| {{ value 'type' | upper }}<|"| } | | | {%- 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:<|"| {{- params 'type' | upper -}}<|"| } | | | {%- 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' | upper == 'OBJECT' -%} | | | type:<|"| {{- response declaration 'type' | upper -}}<|"| } | | | {%- 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 sequence -%} | | | {{- ' ' -}} | | | {%- 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 sequence -%} | | | {%- for item in messages 0 'content' -%} | | | {%- if item 'type' == 'text' -%} | | | {{- item 'text' | trim -}} | | | {%- endif -%} | | | {%- 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 sequence 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 ns text = namespace ok=false -%} | | | {%- if message 'content' is string -%} | | | {%- if role == 'model' -%} | | | {%- set s = strip thinking message 'content' -%} | | | {{- s -}} | | | {%- if s | trim | length 0 -%} | | | {%- set ns text.ok = true -%} | | | {%- endif -%} | | | {%- else -%} | | | {{- message 'content' | trim -}} | | | {%- if message 'content' | trim | length 0 -%} | | | {%- set ns text.ok = true -%} | | | {%- endif -%} | | | {%- endif -%} | | | {%- elif message 'content' is sequence -%} | | | {%- for item in message 'content' -%} | | | {%- if item 'type' == 'text' -%} | | | {%- if role == 'model' -%} | | | {%- set s = strip thinking item 'text' -%} | | | {{- s -}} | | | {%- if s | trim | length 0 -%} | | | {%- set ns text.ok = true -%} | | | {%- endif -%} | | | {%- else -%} | | | {{- item 'text' | trim -}} | | | {%- if item 'text' | trim | length 0 -%} | | | {%- set ns text.ok = true -%} | | | {%- endif -%} | | | {%- 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 -%} | | | {%- if ns.prev message type == 'tool call' and not ns tr out.flag -%} | | | {{- '<|tool response ' -}} | | | {%- elif not ns tr out.flag and not ns text.ok -%} | | | {{- '<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 -%} |