Building Instant RL Loops with Meta Llama Tools and Cerebras

Reinforcement learning (RL) is built around one powerful concept: feedback loops. An agent interacts with an environment, takes actions, receives rewards, and updates its behavior to improve over time.

This idea of experiment → measure → improve isn’t limited to training new models. You can apply the same reinforcement principles at the inference layer: optimizing prompts, generating synthetic data, and iterating rapidly with measurable feedback.

The faster you can complete each iteration loop of experimentation, the faster your system improves.

Cerebras stands apart by building our own hardware purpose-built for serving large models. Cerebras offers a full range of models at 5-20x faster speeds than GPUs you can use out of the box for many production use cases. Cerebras’s speed turns what used to be slow, offline batch jobs into interactive reinforcement loops, where iteration happens in real time.

In this post, we’ll show how to use two open-source tools from Meta’s Llama ecosystem, Prompt-Ops and Synthetic-Data-Kit, with Cerebras Inference to build fast, RL-style workflows that optimize prompts and distill reasoning datasets in real time.

Introducing Llama Tools from Meta

If you’ve tried taking an open model from “cool demo” to “production-grade accuracy,” you already know it’s not (just) about model quality.

It’s about how quickly you can improve prompts, refine data, and test new ideas.

Developers have consistently told us that the hardest parts of working with large language models are:

• Prompt engineering — a slow, manual, trial-and-error process
• Data generation and curation — time-consuming, repetitive, and hard to scale

Meta’s Llama Tools turn these manual loops into automated, measurable processes:

• Prompt-Ops: a Python toolkit for optimizing prompts automatically using model-based feedback
• Synthetic-Data-Kit: a generator and curator for creating large, high-quality synthetic datasets

Using Prompt-Ops to Automatically Optimize Prompts

Prompt engineering has long been more art than science. Developers tweak wording, rerun generations, and “vibe check” results, but this approach doesn’t scale.

Prompt-Ops reframes prompt improvement as a continuous end-to-end optimization reinforcement loop.

Prompt-Ops takes three key inputs:

1. Your existing system prompt
2. A dataset of query–response pairs for evaluation and optimization
3. A configuration file defining model parameters and optimization strategy

From there, Prompt-Ops supports multiple automatic optimization strategies:

• Prompt Duel Optimizer
  Runs tournaments where prompts compete head-to-head. A judge model scores each candidate’s output, and the winners move on. This becomes a reinforcement loop with survival based on reward scores.
• MIPRO (Multi-Prompt Instruction Program Optimization)
  Borrowed from the DSPy framework, this optimizer refines both instructions and few-shot examples together to maximize performance.

Getting Started

Below we give the minimal steps to get started, to learn the entire process, please checkout the entire process in a notebook:

Create a sample project

This will create a directory called my-project with a sample configuration and dataset in the current folder.

Set Up Your API Key

Add your API key to the `.env` file:

Update config.yaml for Cerebras Inference

Here's the configuration for using Cerebras Inference API with ultra-fast Llama 3.3 70B:

Running Prompt Optimization

Now that we have our sample project set up, let's run the prompt optimization process. We'll use the `migrate` command, which takes a configuration file as input and outputs an optimized prompt.

You can find the full e2e notebook here on github: prompt-ops 101 with cerebras inference.

Using Synthetic-Data-Kit to Generate and Curate Data in Real Time

When you deploy large models at scale, you face a familiar challenge: Big models reason well but are expensive to run; small models are efficient but less capable.

One solution is distillation, teaching a smaller “student” model to mimic a larger “teacher” model.

But to do this well, you need thousands of high-quality examples that capture the teacher’s reasoning patterns. Writing those by hand is impossible at scale.

This is where Synthetic-Data-Kit (SDK) comes in. It automates the process of generating, evaluating, and refining synthetic data.

The synthetic-data-kit pipeline requires hundreds or thousands of inference calls:

With slow inference, this becomes a batch job workflow: submit jobs, wait, check results, repeat.

You optimize for "set it and forget it" in your pipeline because the feedback loop is too slow for experimentation instead of focussing on quality curation.

With Cerebras's fast inference, this becomes an interactive workflow: generate, see results, tweak, regenerate all in real time.

The Pipeline: Now With Instant Feedback

Synthetic-data-kit follows a 4-stage pipeline, and Cerebras's instantaneous inference transforms the two most inference-heavy stages:

1. The QA Creation
2. The LLM Judge calls in curation

The Task: Distilling Reasoning to an Edge Model

Let's walk through distilling logical reasoning from a 70B teacher to a 1B edge model—and see how fast iteration changes the workflow.

Step 1: Ingest Raw Materials

Synthetic-data-kit handles PDFs, DOCX, HTML, even YouTube transcripts, converting them to clean text ready for generation.

Step 2: Configure Your Teacher Model & Generation Strategy

Point synthetic-data-kit at Cerebras and customize how you want to generate reasoning traces:

The key insight: By customizing these prompts, you control exactly what kind of reasoning behavior your 70B teacher demonstrates-and that's what your 1B edge model will learn to mimic during fine-tuning.

Step 3: Generate Reasoning Traces (Not Just QA Pairs)

Here's where the --type cot flag matters. Instead of simple QA pairs, you generate Chain-of-Thought reasoning traces that teach your edge model how to think:

The CoT format teaches your 1B model to reason step-by-step, not just memorize answers. This is supervised fine-tuning for reasoning-distilling your 70B teacher's thinking process into your edge model.

With Cerebras's fast inference, you watch 500+ reasoning traces stream in instead of queuing overnight jobs. This is your teacher model demonstrating its reasoning on 500 different problems, fast enough that you stay in the flow.

Step 4: Curate with Instant Judging

Now use the same 70B model to judge quality:

Another 500+ inference calls, this time for judging. With slow endpoints, this becomes the second waiting period of your day. With Cerebras, it's fast enough to keep experimenting.

Step 5: Save for Reasoning SFT

This is reasoning distillation: your 70B teacher's step-by-step thinking compressed.

Step 6: Iterate on Prompt Strategy

Here's where fast inference really matters. You notice your reasoning traces could be more detailed, so you tweak the prompt:

Why Cerebras Is Built for This

Reinforcement learning thrives on iteration speed, and so does AI engineering. Cerebras makes RL-style feedback loops practical at scale:

This transforms data generation from a slow, offline pipeline into an interactive, continuous improvement system.

With Llama’s open-source tools and Cerebras’s inference, you can now build real-time RL loops for both prompt optimization and data distillation, bringing reinforcement learning principles directly into day-to-day AI development.

Acknowledgement: Justin Lee, Sanyam Bhutani from Meta