Config file

The configuration file controls the training pipeline through four main sections: base, tuning, evaluation, and synthgen. Each section handles a specific aspect of the model training process.

File format

The configuration file supports two formats depending on how you interact with distil labs:

• Webapp: Use JSON format (.json file)
• API: Use YAML format (.yaml file)

Both formats are functionally equivalent—choose based on your workflow. Examples in this documentation show YAML, but the JSON equivalent is straightforward:

# YAML (API)
base:
  task: question-answering
  student_model_name: Llama-3.2-3B-Instruct

// JSON (Webapp)
{
  "base": {
    "task": "question-answering",
    "student_model_name": "Llama-3.2-3B-Instruct"
  }
}

Configuration structure

base:
  # General parameters (task is required)
  task: classification

tuning:
  # Fine-tuning parameters
  num_train_epochs: 32

evaluation:
  # Evaluation parameters
  num_few_shot_examples: 1

synthgen:
  # Synthetic data generation parameters
  generation_target: 10000

Base configuration

General parameters relevant to the overall task.

Parameter	Type	Default	Description
task	string	required	Type of NLP task to be solved. See supported task types below.
student_model_name	string	Llama-3.2-1B-Instruct	Base model to use for the student model. This is the model we finetune for your use-case.
teacher_model_name	string	Llama-3.3-70B-Instruct	Teacher model used to generate synthetic data and from which we distil knowledge.
random_seed	integer | null	123	Random seed used across distillib for reproducible random sampling.

Supported task types

Task	Value	Description
Question Answering	question-answering	Extract or generate answers from text based on queries
Classification	classification	Assign text to categories from a fixed set
Tool Calling	tool-calling-closed-book	Select and invoke functions based on user requests
Multi-turn Tool Calling	multi-turn-tool-calling-closed-book	Handle multi-step conversations with function calls
Open Book QA (RAG)	question-answering-open-book	Answer questions using provided context passages
Closed Book QA	question-answering-closed-book	Answer questions using knowledge learned during training

Supported student models

Model	Value
Llama 3.2 1B Instruct	Llama-3.2-1B-Instruct
Llama 3.2 3B Instruct	Llama-3.2-3B-Instruct
Llama 3.1 8B Instruct	Llama-3.1-8B-Instruct
SmolLM2 135M	SmolLM2-135M-Instruct
SmolLM2 1.7B	SmolLM2-1.7B-Instruct
FunctionGemma 270M	functiongemma-270m-it
Gemma 3 270M	gemma-3-270m-it
Gemma 3 1B	gemma-3-1b-it
Gemma 3 4B	gemma-3-4b-it
Qwen3 0.6B	Qwen3-0.6B
Qwen3 1.7B	Qwen3-1.7B
Qwen3 4B	Qwen3-4B-Instruct-2507
Qwen3 8B	Qwen3-8B
IBM Granite 3.1 8B	granite-3.1-8b-instruct
IBM Granite 3.3 8B	granite-3.3-8b-instruct

Supported teacher models

Model	Value
DeepSeek R1	deepseek.r1
DeepSeek V3.1	deepseek.v3.1
Qwen3 235B A22B	Qwen3-235B-A22B-Instruct-2507
Qwen3 480B A35B Coder	Qwen3-480B-A35B-Coder
Qwen2.5 VL 72B	Qwen2.5-VL-72B-Instruct
Llama 3.1 405B Instruct	Llama-3.1-405B-Instruct
Llama 3.1 8B Instruct	Llama-3.1-8B-Instruct
Llama 3.3 70B Instruct	Llama-3.3-70B-Instruct
GPT OSS 20B	openai.gpt-oss-20b
GPT OSS 120B	openai.gpt-oss-120b
GPT OSS 120B Thinking	openai.gpt-oss-120b-thinking

---

Tuning configuration

Parameters controlling the finetuning of the student model.

Parameter	Type	Default	Description
learning_rate	float	5e-5	The initial learning rate for AdamW optimizer.
learning_rate_scheduler	string	linear	The scheduler type to use. Options: cosine, linear, constant.
weight_decay	float	0.0	Weight decay applied to all layers except bias and LayerNorm weights in AdamW optimizer.
warmup_ratio	float	0.05	Ratio of total training steps used for linear warmup from 0 to learning_rate.
bf16	boolean	true	Whether to use bf16 16-bit (mixed) precision training instead of 32-bit training.
use_lora	boolean	true	Whether to use LoRA for student training.
lora_r	integer	64	LoRA attention dimension (rank). Only used if use_lora is true.
lora_alpha_multiplier	integer	1	Alpha parameter for LoRA scaling is lora_r * lora_alpha_multiplier. Only used if use_lora is true.
per_device_train_batch_size	integer	1	Batch size per GPU/device for training.
per_device_eval_batch_size	integer	1	Batch size per GPU/device for evaluation.
num_train_epochs	integer	4	Total number of training epochs.
train_eval_split	float	0.2	Fraction of training data used for evaluation. Must be between 0 and 1 (exclusive).
gradient_accumulation_steps	integer	1	Number of update steps to accumulate gradients before performing a backward/update pass. Effectively multiplies the batch size by this factor without increasing memory usage.
num_few_shot_examples_student	integer	0	Number of few-shot examples when running student evaluation and tuning. If above 0, at least one example per class is used for classification tasks.

RLVR (Reinforcement Learning with Verifiable Rewards)

RLVR is an optional reinforcement learning stage that runs after SFT finetuning. It uses reward signals from an LLM-as-a-judge to further improve model performance. Set rlvr_dataset_size to a value greater than 0 to enable it.

Parameter	Type	Default	Description
rlvr_dataset_size	float	0.0	Proportion of the dataset to use for the RLVR split. Must be between 0.0 and 1.0. Default 0.0 means RLVR is disabled.
rlvr_llm_as_a_judge_model_name	string	openai.gpt-oss-20b	Model used to power the LLM-as-a-judge for RLVR reward signals.
rlvr_per_device_batch_size	integer	6	Batch size per GPU/device for RLVR training and evaluation. Must be a multiple of rlvr_num_generations.
rlvr_num_generations	integer	6	Number of generations per prompt during RLVR training.
rlvr_num_train_epochs	integer	1	Number of training epochs for RLVR finetuning.

---

Evaluation configuration

Parameters used in teacher evaluation.

Parameter	Type	Default	Description
num_few_shot_examples	integer	1	Number of few-shot examples when running teacher evaluation. If above 0, at least one example per class is used for classification tasks.
llm_as_a_judge_model_name	string	openai.gpt-oss-120b	Model used to power the LLM-as-a-judge evaluation.
expand_tool_calling_turns	boolean	true	If true, each line in multi-turn tool calling test files is expanded into multiple evaluation lines, each ending at a tool call.
batch_size	integer	4	(Deprecated) Batch size for model evaluation.

---

Synthetic generation configuration

Parameters for fine-grained control over synthetic data generation.

Parameter	Type	Default	Description
generation_target	integer	10000	Target number of synthetic examples to generate. For Closed-Book QA, this is calculated as len(unstructured_data) * generation_per_unstructured_context.
generation_in_single_call	integer	4	Number of examples to generate per teacher/LLM invocation.
generation_iteration_size	integer	128	Batch size for the generate-validate cycle.
generation_per_unstructured_context	integer | null	null	Examples to generate per unstructured context. Only used with question-answering-closed-book task. Overwrites generation_target when set.
num_positive_exemplars_per_generation	integer	2	Number of in-context examples for the class/task being generated.
num_negative_exemplars_per_generation	integer	2	Number of in-context examples for classes not being generated. Only used for classification tasks.
num_unlabelled_exemplars_per_generation	integer	2	Number of unlabelled examples provided during each teacher invocation.
validation_max_total_length	integer	10000	Maximum total length (input + output) of generated examples in characters.
validation_similarity_threshold	float	0.95	Similarity threshold for deduplication. Generated data with similarity above this threshold to seed data are removed.
validation_max_answer_length	integer	8192	(Deprecated) Use validation_max_total_length instead.
teacher_temperature	float	0.7	Temperature for teacher output. Controls balance between predictability and creativity. Must be between 0.0 and 1.0.
teacher_max_tokens	integer | null	null	Maximum tokens in the generated response.
match_generated_distribution_to_seed	boolean	false	Match generated data class distribution to seed data. Only used for classification tasks.
num_distractor_context_blocks	integer	0	Number of distractor context blocks per example. Setting above zero enables RAFT training.
output_is_json	boolean	false	Only generate synthetic data with valid JSON outputs. Only relevant for QA tasks.
basic_mutators_to_use	list[string]	["complexity"]	List of basic mutators to use for data generation. Supported options: complexity, length, specificity.
mutation_topics	list[list[string]] | list[string]	[]	Selection of topics to sample from to guide the generation process.
parallel_llm_calls	boolean	false	If true, call the LLM in parallel during data generation and evaluation.

---

Example configuration

Minimal configuration

base:
  task: question-answering
  student_model_name: Llama-3.2-3B-Instruct
  teacher_model_name: openai.gpt-oss-120b

Full configuration example

base:
  task: question-answering-open-book
  student_model_name: Qwen3-1.7B
  teacher_model_name: openai.gpt-oss-120b
  random_seed: 42

tuning:
  learning_rate: 1e-4
  learning_rate_scheduler: cosine
  use_lora: true
  lora_r: 32
  num_train_epochs: 3
  train_eval_split: 0.15

evaluation:
  num_few_shot_examples: 2

synthgen:
  generation_target: 5000
  generation_in_single_call: 8
  teacher_temperature: 0.6
  validation_similarity_threshold: 0.9

---

Model-specific notes

DeepSeek R1

When using deepseek.r1 as the teacher model, the recommended temperature range is 0.5 to 0.7. Configurations with temperatures outside this range will raise a validation error.

GPT OSS 120B Thinking

The openai.gpt-oss-120b-thinking model uses a medium reasoning effort setting by default for enhanced chain-of-thought capabilities.

Tool Calling

Tool calling tasks have specific model compatibility requirements:

Student models: Only Qwen3 and Llama 3-family models are supported for tool-calling-closed-book and multi-turn-tool-calling-closed-book tasks.

Teacher models for multi-turn: Multi-turn tool calling (multi-turn-tool-calling-closed-book) requires one of the following teacher models:

• Qwen3-235B-A22B-Instruct-2507
• Llama-3.1-405B-Instruct
• openai.gpt-oss-120b