devops-thiago/classone-gemma4-e2b
0670
1{#
2 Template: Google Gemma 4 Canonical Chat Template
3 Author: Google Gemma Engineering Team
4 Published: 2026-07-09
5 Context: Fixed tool-calling loops, turn closures, and thinking content-ordering.
6#}
7{%- macro format_parameters(properties, required, filter_keys=false) -%}
8 {%- set standard_keys = ['description', 'type', 'properties', 'required', 'nullable'] -%}
9 {%- set ns = namespace(found_first=false) -%}
10 {%- for key, value in properties | dictsort -%}
11 {%- set add_comma = false -%}
12 {%- if not filter_keys or key not in standard_keys -%}
13 {%- if ns.found_first %},{% endif -%}
14 {%- set ns.found_first = true -%}
15 {{ key }}:{
16 {%- if value['description'] -%}
17 description:<|"|>{{ value['description'] }}<|"|>
18 {%- set add_comma = true -%}
19 {%- endif -%}
20 {%- if value['type'] | upper == 'STRING' -%}
21 {%- if value['enum'] -%}
22 {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
23 enum:{{ format_argument(value['enum']) }}
24 {%- endif -%}
25 {%- elif value['type'] | upper == 'ARRAY' -%}
26 {%- if value['items'] is mapping and value['items'] -%}
27 {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
28 items:{
29 {%- set ns_items = namespace(found_first=false) -%}
30 {%- for item_key, item_value in value['items'] | dictsort -%}
31 {%- if item_value is not none -%}
32 {%- if ns_items.found_first %},{% endif -%}
33 {%- set ns_items.found_first = true -%}
34 {%- if item_key == 'properties' -%}
35 properties:{
36 {%- if item_value is mapping -%}
37 {{- format_parameters(item_value, value['items']['required'] | default([])) -}}
38 {%- endif -%}
39 }
40 {%- elif item_key == 'required' -%}
41 required:[
42 {%- for req_item in item_value -%}
43 <|"|>{{- req_item -}}<|"|>
44 {%- if not loop.last %},{% endif -%}
45 {%- endfor -%}
46 ]
47 {%- elif item_key == 'type' -%}
48 {%- if item_value is string -%}
49 type:{{ format_argument(item_value | upper) }}
50 {%- else -%}
51 type:{{ format_argument(item_value | map('upper') | list) }}
52 {%- endif -%}
53 {%- else -%}
54 {{ item_key }}:{{ format_argument(item_value) }}
55 {%- endif -%}
56 {%- endif -%}
57 {%- endfor -%}
58 }
59 {%- endif -%}
60 {%- endif -%}
61 {%- if value['nullable'] %}
62 {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
63 nullable:true
64 {%- endif -%}
65 {%- if value['type'] | upper == 'OBJECT' -%}
66 {%- if value['properties'] is defined and value['properties'] is mapping -%}
67 {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
68 properties:{
69 {{- format_parameters(value['properties'], value['required'] | default([])) -}}
70 }
71 {%- elif value is mapping -%}
72 {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
73 properties:{
74 {{- format_parameters(value, value['required'] | default([]), filter_keys=true) -}}
75 }
76 {%- endif -%}
77 {%- if value['required'] -%}
78 {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
79 required:[
80 {%- for item in value['required'] | default([]) -%}
81 <|"|>{{- item -}}<|"|>
82 {%- if not loop.last %},{% endif -%}
83 {%- endfor -%}
84 ]
85 {%- endif -%}
86 {%- endif -%}
87 {%- if add_comma %},{%- else -%} {%- set add_comma = true -%} {% endif -%}
88 type:<|"|>{{ value['type'] | upper }}<|"|>}
89 {%- endif -%}
90 {%- endfor -%}
91{%- endmacro -%}
92{%- macro format_function_declaration(tool_data) -%}
93 declaration:{{- tool_data['function']['name'] -}}{description:<|"|>{{- tool_data['function']['description'] -}}<|"|>
94 {%- set params = tool_data['function']['parameters'] -%}
95 {%- if params -%}
96 ,parameters:{
97 {%- if params['properties'] -%}
98 properties:{ {{- format_parameters(params['properties'], params['required']) -}} },
99 {%- endif -%}
100 {%- if params['required'] -%}
101 required:[
102 {%- for item in params['required'] -%}
103 <|"|>{{- item -}}<|"|>
104 {{- ',' if not loop.last -}}
105 {%- endfor -%}
106 ],
107 {%- endif -%}
108 {%- if params['type'] -%}
109 type:<|"|>{{- params['type'] | upper -}}<|"|>}
110 {%- endif -%}
111 {%- endif -%}
112 {%- if 'response' in tool_data['function'] -%}
113 {%- set response_declaration = tool_data['function']['response'] -%}
114 ,response:{
115 {%- if response_declaration['description'] -%}
116 description:<|"|>{{- response_declaration['description'] -}}<|"|>,
117 {%- endif -%}
118 {%- if response_declaration['type'] | upper == 'OBJECT' -%}
119 type:<|"|>{{- response_declaration['type'] | upper -}}<|"|>}
120 {%- endif -%}
121 {%- endif -%}
122 }
123{%- endmacro -%}
124{%- macro format_argument(argument, escape_keys=True) -%}
125 {%- if argument is none -%}
126 {{- 'null' -}}
127 {%- elif argument is string -%}
128 {{- '<|"|>' + argument + '<|"|>' -}}
129 {%- elif argument is boolean -%}
130 {{- 'true' if argument else 'false' -}}
131 {%- elif argument is mapping -%}
132 {{- '{' -}}
133 {%- set ns = namespace(found_first=false) -%}
134 {%- for key, value in argument | dictsort -%}
135 {%- if ns.found_first %},{% endif -%}
136 {%- set ns.found_first = true -%}
137 {%- if escape_keys -%}
138 {{- '<|"|>' + key + '<|"|>' -}}
139 {%- else -%}
140 {{- key -}}
141 {%- endif -%}
142 :{{- format_argument(value, escape_keys=escape_keys) -}}
143 {%- endfor -%}
144 {{- '}' -}}
145 {%- elif argument is sequence -%}
146 {{- '[' -}}
147 {%- for item in argument -%}
148 {{- format_argument(item, escape_keys=escape_keys) -}}
149 {%- if not loop.last %},{% endif -%}
150 {%- endfor -%}
151 {{- ']' -}}
152 {%- else -%}
153 {{- argument -}}
154 {%- endif -%}
155{%- endmacro -%}
156{%- macro strip_thinking(text) -%}
157 {%- set ns = namespace(result='') -%}
158 {%- for part in text.split('<channel|>') -%}
159 {%- if '<|channel>' in part -%}
160 {%- set ns.result = ns.result + part.split('<|channel>')[0] -%}
161 {%- else -%}
162 {%- set ns.result = ns.result + part -%}
163 {%- endif -%}
164 {%- endfor -%}
165 {{- ns.result | trim -}}
166{%- endmacro -%}
167
168{%- macro format_tool_response_block(tool_name, response) -%}
169 {{- '<|tool_response>' -}}
170 {%- if response is mapping -%}
171 {{- 'response:' + tool_name + '{' -}}
172 {%- for key, value in response | dictsort -%}
173 {{- key -}}:{{- format_argument(value, escape_keys=False) -}}
174 {%- if not loop.last %},{% endif -%}
175 {%- endfor -%}
176 {{- '}' -}}
177 {%- else -%}
178 {{- 'response:' + tool_name + '{value:' + format_argument(response, escape_keys=False) + '}' -}}
179 {%- endif -%}
180 {{- '<tool_response|>' -}}
181{%- endmacro -%}
182
183{#- ===== SETUP ===== -#}
184{%- set ns = namespace(prev_message_type=None, prev_non_tool_role=None) -%}
185{%- set loop_messages = messages -%}
186{%- set enable_thinking = enable_thinking | default(false) -%}
187{%- set preserve_thinking = preserve_thinking | default(false) -%}
188{{- bos_token -}}
189{#- Handle System/Tool Definitions Block -#}
190{%- if enable_thinking or tools or (messages and messages[0]['role'] in ['system', 'developer']) -%}
191 {{- '<|turn>system\n' -}}
192 {#- Inject Thinking token at the very top of the FIRST system turn -#}
193 {%- if enable_thinking -%}
194 {{- '<|think|>\n' -}}
195 {%- set ns.prev_message_type = 'think' -%}
196 {%- endif -%}
197 {%- if messages and messages[0]['role'] in ['system', 'developer'] -%}
198 {%- if messages[0]['content'] is string -%}
199 {{- messages[0]['content'] | trim -}}
200 {%- elif messages[0]['content'] is sequence -%}
201 {%- for item in messages[0]['content'] -%}
202 {{- item['text'] | trim + ' '-}}
203 {%- endfor -%}
204 {%- endif -%}
205 {%- set loop_messages = messages[1:] -%}
206 {%- endif -%}
207 {%- if tools -%}
208 {%- for tool in tools %}
209 {{- '<|tool>' -}}
210 {{- format_function_declaration(tool) | trim -}}
211 {{- '<tool|>' -}}
212 {%- endfor %}
213 {%- set ns.prev_message_type = 'tool' -%}
214 {%- endif -%}
215 {{- '<turn|>\n' -}}
216{%- endif %}
217
218{#- Pre-scan: find last user message index for reasoning guard -#}
219{%- set ns_turn = namespace(last_user_idx=-1) -%}
220{%- for i in range(loop_messages | length) -%}
221 {%- if loop_messages[i]['role'] == 'user' -%}
222 {%- set ns_turn.last_user_idx = i -%}
223 {%- endif -%}
224{%- endfor -%}
225
226{#- Loop through messages -#}
227{%- for message in loop_messages -%}
228 {%- if message['role'] != 'tool' -%}
229 {%- set ns.prev_message_type = None -%}
230 {%- set role = 'model' if message['role'] == 'assistant' else message['role'] -%}
231 {#- Detect continuation using tracked state — O(1) instead of O(n) backward scan -#}
232 {%- set continue_same_model_turn = (role == 'model' and ns.prev_non_tool_role == 'assistant') -%}
233 {%- if not continue_same_model_turn -%}
234 {{- '<|turn>' + role + '\n' }}
235 {%- endif -%}
236
237 {#- Render reasoning/reasoning_content as thinking channel -#}
238 {%- set thinking_text = message.get('reasoning') or message.get('reasoning_content') -%}
239 {%- set thinking_gate = (loop.index0 > ns_turn.last_user_idx) or (preserve_thinking and message.get('tool_calls')) -%}
240 {%- if thinking_text and thinking_gate -%}
241 {{- '<|channel>thought\n' + thinking_text + '\n<channel|>' -}}
242 {%- endif -%}
243
244 {%- if message.get('tool_calls') -%}
245 {%- for tool_call in message.get('tool_calls') -%}
246 {%- set function = tool_call['function'] -%}
247 {{- '<|tool_call>call:' + function['name'] + '{' -}}
248 {%- if function['arguments'] is mapping -%}
249 {%- set ns_args = namespace(found_first=false) -%}
250 {%- for key, value in function['arguments'] | dictsort -%}
251 {%- if ns_args.found_first %},{% endif -%}
252 {%- set ns_args.found_first = true -%}
253 {{- key -}}:{{- format_argument(value, escape_keys=False) -}}
254 {%- endfor -%}
255 {%- elif function['arguments'] is none -%}
256 {%- else -%}
257 {{- raise_exception(
258 "chat_template: tool_calls[].function.arguments must be a "
259 "JSON object (mapping), not a string. Deserialize arguments "
260 "before passing to the template."
261 ) -}}
262 {%- endif -%}
263 {{- '}<tool_call|>' -}}
264 {%- endfor -%}
265 {%- set ns.prev_message_type = 'tool_call' -%}
266 {%- endif -%}
267
268 {%- set ns_tr_out = namespace(flag=false) -%}
269 {%- if message.get('tool_responses') -%}
270 {#- Legacy: tool_responses embedded on the assistant message (Google/Gemma native) -#}
271 {%- for tool_response in message.get('tool_responses') -%}
272 {{- format_tool_response_block(tool_response['name'] | default('unknown', true), tool_response['response']) -}}
273 {%- set ns_tr_out.flag = true -%}
274 {%- set ns.prev_message_type = 'tool_response' -%}
275 {%- endfor -%}
276 {%- elif message.get('tool_calls') -%}
277 {#- OpenAI Chat Completions: forward-scan consecutive role:tool messages -#}
278 {%- set ns_tool_scan = namespace(stopped=false) -%}
279 {%- for k in range(loop.index0 + 1, loop_messages | length) -%}
280 {%- if ns_tool_scan.stopped -%}
281 {%- elif loop_messages[k]['role'] != 'tool' -%}
282 {%- set ns_tool_scan.stopped = true -%}
283 {%- else -%}
284 {%- set follow = loop_messages[k] -%}
285 {#- Resolve tool_call_id to function name -#}
286 {%- set ns_tname = namespace(name=follow.get('name') or 'unknown') -%}
287 {%- for tc in message.get('tool_calls') -%}
288 {%- if tc.get('id') == follow.get('tool_call_id') -%}
289 {%- set ns_tname.name = tc['function']['name'] -%}
290 {%- endif -%}
291 {%- endfor -%}
292 {#- Handle content as string or content-parts array -#}
293 {%- set tool_body = follow.get('content') -%}
294 {%- if tool_body is string -%}
295 {{- format_tool_response_block(ns_tname.name, tool_body) -}}
296 {%- elif tool_body is sequence and tool_body is not string -%}
297 {%- set ns_txt = namespace(s='') -%}
298 {%- for part in tool_body -%}
299 {%- if part.get('type') == 'text' -%}
300 {%- set ns_txt.s = ns_txt.s + (part.get('text') | default('')) -%}
301 {%- endif -%}
302 {%- endfor -%}
303 {{- format_tool_response_block(ns_tname.name, ns_txt.s) -}}
304 {%- for part in tool_body -%}
305 {%- if part.get('type') in ['image', 'image_url'] -%}
306 {{- '<|image|>' -}}
307 {%- elif part.get('type') in ['audio', 'input_audio'] -%}
308 {{- '<|audio|>' -}}
309 {%- elif part.get('type') == 'video' -%}
310 {{- '<|video|>' -}}
311 {%- endif -%}
312 {%- endfor -%}
313 {%- else -%}
314 {{- format_tool_response_block(ns_tname.name, tool_body) -}}
315 {%- endif -%}
316 {%- set ns_tr_out.flag = true -%}
317 {%- set ns.prev_message_type = 'tool_response' -%}
318 {%- endif -%}
319 {%- endfor -%}
320 {%- endif -%}
321
322 {%- set captured_content -%}
323 {%- if message.get('content') is string -%}
324 {%- if role == 'model' -%}
325 {{- strip_thinking(message['content']) -}}
326 {%- else -%}
327 {{- message['content'] | trim -}}
328 {%- endif -%}
329 {%- elif message.get('content') is sequence -%}
330 {%- for item in message['content'] -%}
331 {%- if item.get('type') == 'text' -%}
332 {%- if role == 'model' -%}
333 {{- strip_thinking(item['text']) -}}
334 {%- else -%}
335 {{- item['text'] | trim -}}
336 {%- endif -%}
337 {%- elif item.get('type') in ['image', 'image_url'] -%}
338 {{- '<|image|>' -}}
339 {%- elif item.get('type') in ['audio', 'input_audio'] -%}
340 {{- '<|audio|>' -}}
341 {%- elif item.get('type') == 'video' -%}
342 {{- '<|video|>' -}}
343 {%- endif -%}
344 {%- endfor -%}
345 {%- endif -%}
346 {%- endset -%}
347
348 {{- captured_content -}}
349 {%- set has_content = captured_content | trim | length > 0 -%}
350
351 {#- Forward-scan: find next non-tool message role for continuation detection -#}
352 {%- set next_nt = namespace(role=None, found=false) -%}
353 {%- for j in range(loop.index0 + 1, loop_messages | length) -%}
354 {%- if not next_nt.found -%}
355 {%- if loop_messages[j]['role'] != 'tool' -%}
356 {%- set next_nt.role = loop_messages[j]['role'] -%}
357 {%- set next_nt.found = true -%}
358 {%- endif -%}
359 {%- endif -%}
360 {%- endfor -%}
361
362 {%- set continues_into_next = (
363 role == 'model'
364 and next_nt.role == 'assistant'
365 and (not message.get('tool_calls') or ns_tr_out.flag)
366 ) -%}
367
368 {%- if ns.prev_message_type == 'tool_call' and not ns_tr_out.flag -%}
369 {{- '<|tool_response>' -}}
370 {%- elif continues_into_next -%}
371 {%- elif not (ns_tr_out.flag and not has_content and not next_nt.found) -%}
372 {{- '<turn|>\n' -}}
373 {%- endif -%}
374
375 {#- Track previous non-tool role for next iteration (avoids O(n) backward scan) -#}
376 {%- set ns.prev_non_tool_role = message['role'] -%}
377 {%- endif -%}
378{%- endfor -%}
379
380{%- if add_generation_prompt -%}
381 {%- if ns.prev_message_type != 'tool_response' and ns.prev_message_type != 'tool_call' -%}
382 {{- '<|turn>model\n' -}}
383 {%- elif ns.prev_message_type == 'tool_response' and enable_thinking -%}
384 {{- '<|channel>thought\n' -}}
385 {%- endif -%}
386{%- endif -%}
387