llama-stack-mirror/docs/source/getting_started/index.md

Quick Start

Llama Stack is a stateful service with REST APIs to support seamless transition of AI applications across different environments. The server can be run in a variety of ways, including as a standalone binary, Docker container, or hosted service. You can build and test using a local server first and deploy to a hosted endpoint for production.

In this guide, we'll walk through how to build a RAG agent locally using Llama Stack with Ollama to run inference on a Llama Model.

1. Start Ollama

ollama run llama3.2:3b --keepalive 60m

By default, Ollama keeps the model loaded in memory for 5 minutes which can be too short. We set the --keepalive flag to 60 minutes to ensure the model remains loaded for sometime.

:class: tip

If you do not have ollama, you can install it from [here](https://ollama.com/download).

2. Run Llama Stack locally

We use uv to setup a virtual environment and install the Llama Stack package.

:::{dropdown} [Click to Open] Instructions to setup uv

Install uv to setup your virtual environment.

For macOS and Linux:

curl -LsSf https://astral.sh/uv/install.sh | sh

For Windows:

Use irm to download the script and execute it with iex:

powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | iex"

Setup venv

uv venv --python 3.10
source .venv/bin/activate

:::

Install the Llama Stack package

uv pip install -U llama-stack

Build and Run the Llama Stack server for Ollama.

INFERENCE_MODEL=llama3.2:3b llama stack build --template ollama --image-type venv --run

You will see the output end like below:

...
INFO:     Application startup complete.
INFO:     Uvicorn running on http://['::', '0.0.0.0']:8321 (Press CTRL+C to quit)

Now you can use the llama stack client to run inference and build agents!

3. Client CLI

Install the client package

pip install llama-stack-client

:::{dropdown} OR reuse server setup Open a new terminal and navigate to the same directory you started the server from.

Setup venv (llama-stack already includes the llama-stack-client package)

source .venv/bin/activate

:::

3.1 Configure the client to point to the local server

llama-stack-client configure --endpoint http://localhost:8321 --api-key none

You will see the below:

Done! You can now use the Llama Stack Client CLI with endpoint http://localhost:8321

3.2 List available models

llama-stack-client models list

Available Models

┏━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃ model_type      ┃ identifier                          ┃ provider_resource_id                ┃ metadata                                  ┃ provider_id     ┃
┡━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ embedding       │ all-MiniLM-L6-v2                    │ all-minilm:latest                   │ {'embedding_dimension': 384.0}            │ ollama          │
├─────────────────┼─────────────────────────────────────┼─────────────────────────────────────┼───────────────────────────────────────────┼─────────────────┤
│ llm             │ llama3.2:3b                         │ llama3.2:3b                         │                                           │ ollama          │
└─────────────────┴─────────────────────────────────────┴─────────────────────────────────────┴───────────────────────────────────────────┴─────────────────┘

Total models: 2

3.3 Test basic inference

llama-stack-client inference chat-completion --message "tell me a joke"

Sample output:

ChatCompletionResponse(
    completion_message=CompletionMessage(
        content="Here's one:\n\nWhat do you call a fake noodle?\n\nAn impasta!",
        role="assistant",
        stop_reason="end_of_turn",
        tool_calls=[],
    ),
    logprobs=None,
    metrics=[
        Metric(metric="prompt_tokens", value=14.0, unit=None),
        Metric(metric="completion_tokens", value=27.0, unit=None),
        Metric(metric="total_tokens", value=41.0, unit=None),
    ],
)

4. Python SDK

Install the python client

pip install llama-stack-client

:::{dropdown} OR reuse server setup Open a new terminal and navigate to the same directory you started the server from.

Setup venv (llama-stack already includes the llama-stack-client package)

source .venv/bin/activate

:::

4.1 Basic Inference

Create a file inference.py and add the following code:

from llama_stack_client import LlamaStackClient

client = LlamaStackClient(base_url=f"http://localhost:8321")

# List available models
models = client.models.list()

# Select the first LLM
llm = next(m for m in models if m.model_type == "llm")
model_id = llm.identifier

print("Model:", model_id)

response = client.inference.chat_completion(
    model_id=model_id,
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Write a haiku about coding"},
    ],
)
print(response.completion_message.content)

Run the script

python inference.py

Sample output:

Model: llama3.2:3b-instruct-fp16
Here is a haiku about coding:

Lines of code unfold
Logic flows through digital night
Beauty in the bits

4.2. Basic Agent

Create a file agent.py and add the following code:

from llama_stack_client import LlamaStackClient
from llama_stack_client import Agent, AgentEventLogger
from rich.pretty import pprint
import uuid

client = LlamaStackClient(base_url=f"http://localhost:8321")

models = client.models.list()
llm = next(m for m in models if m.model_type == "llm")
model_id = llm.identifier

agent = Agent(client, model=model_id, instructions="You are a helpful assistant.")

s_id = agent.create_session(session_name=f"s{uuid.uuid4().hex}")

print("Non-streaming ...")
response = agent.create_turn(
    messages=[{"role": "user", "content": "Who are you?"}],
    session_id=s_id,
    stream=False,
)
print("agent>", response.output_message.content)

print("Streaming ...")
stream = agent.create_turn(
    messages=[{"role": "user", "content": "Who are you?"}], session_id=s_id, stream=True
)
for event in stream:
    pprint(event)

print("Streaming with print helper...")
stream = agent.create_turn(
    messages=[{"role": "user", "content": "Who are you?"}], session_id=s_id, stream=True
)
for event in AgentEventLogger().log(stream):
    event.print()

Run the script:

python agent.py

:::{dropdown} Sample output

Non-streaming ...
agent> I'm an artificial intelligence designed to assist and communicate with users like you. I don't have a personal identity, but I'm here to provide information, answer questions, and help with tasks to the best of my abilities.

I can be used for a wide range of purposes, such as:

* Providing definitions and explanations
* Offering suggestions and ideas
* Helping with language translation
* Assisting with writing and proofreading
* Generating text or responses to questions
* Playing simple games or chatting about topics of interest

I'm constantly learning and improving my abilities, so feel free to ask me anything, and I'll do my best to help!

Streaming ...
AgentTurnResponseStreamChunk(
│   event=TurnResponseEvent(
│   │   payload=AgentTurnResponseStepStartPayload(
│   │   │   event_type='step_start',
│   │   │   step_id='69831607-fa75-424a-949b-e2049e3129d1',
│   │   │   step_type='inference',
│   │   │   metadata={}
│   │   )
│   )
)
AgentTurnResponseStreamChunk(
│   event=TurnResponseEvent(
│   │   payload=AgentTurnResponseStepProgressPayload(
│   │   │   delta=TextDelta(text='As', type='text'),
│   │   │   event_type='step_progress',
│   │   │   step_id='69831607-fa75-424a-949b-e2049e3129d1',
│   │   │   step_type='inference'
│   │   )
│   )
)
AgentTurnResponseStreamChunk(
│   event=TurnResponseEvent(
│   │   payload=AgentTurnResponseStepProgressPayload(
│   │   │   delta=TextDelta(text=' a', type='text'),
│   │   │   event_type='step_progress',
│   │   │   step_id='69831607-fa75-424a-949b-e2049e3129d1',
│   │   │   step_type='inference'
│   │   )
│   )
)
...
AgentTurnResponseStreamChunk(
│   event=TurnResponseEvent(
│   │   payload=AgentTurnResponseStepCompletePayload(
│   │   │   event_type='step_complete',
│   │   │   step_details=InferenceStep(
│   │   │   │   api_model_response=CompletionMessage(
│   │   │   │   │   content='As a conversational AI, I don\'t have a personal identity in the classical sense. I exist as a program running on computer servers, designed to process and respond to text-based inputs.\n\nI\'m an instance of a type of artificial intelligence called a "language model," which is trained on vast amounts of text data to generate human-like responses. My primary function is to understand and respond to natural language inputs, like our conversation right now.\n\nThink of me as a virtual assistant, a chatbot, or a conversational interface – I\'m here to provide information, answer questions, and engage in conversation to the best of my abilities. I don\'t have feelings, emotions, or consciousness like humans do, but I\'m designed to simulate human-like interactions to make our conversations feel more natural and helpful.\n\nSo, that\'s me in a nutshell! What can I help you with today?',
│   │   │   │   │   role='assistant',
│   │   │   │   │   stop_reason='end_of_turn',
│   │   │   │   │   tool_calls=[]
│   │   │   │   ),
│   │   │   │   step_id='69831607-fa75-424a-949b-e2049e3129d1',
│   │   │   │   step_type='inference',
│   │   │   │   turn_id='8b360202-f7cb-4786-baa9-166a1b46e2ca',
│   │   │   │   completed_at=datetime.datetime(2025, 4, 3, 1, 15, 21, 716174, tzinfo=TzInfo(UTC)),
│   │   │   │   started_at=datetime.datetime(2025, 4, 3, 1, 15, 14, 28823, tzinfo=TzInfo(UTC))
│   │   │   ),
│   │   │   step_id='69831607-fa75-424a-949b-e2049e3129d1',
│   │   │   step_type='inference'
│   │   )
│   )
)
AgentTurnResponseStreamChunk(
│   event=TurnResponseEvent(
│   │   payload=AgentTurnResponseTurnCompletePayload(
│   │   │   event_type='turn_complete',
│   │   │   turn=Turn(
│   │   │   │   input_messages=[UserMessage(content='Who are you?', role='user', context=None)],
│   │   │   │   output_message=CompletionMessage(
│   │   │   │   │   content='As a conversational AI, I don\'t have a personal identity in the classical sense. I exist as a program running on computer servers, designed to process and respond to text-based inputs.\n\nI\'m an instance of a type of artificial intelligence called a "language model," which is trained on vast amounts of text data to generate human-like responses. My primary function is to understand and respond to natural language inputs, like our conversation right now.\n\nThink of me as a virtual assistant, a chatbot, or a conversational interface – I\'m here to provide information, answer questions, and engage in conversation to the best of my abilities. I don\'t have feelings, emotions, or consciousness like humans do, but I\'m designed to simulate human-like interactions to make our conversations feel more natural and helpful.\n\nSo, that\'s me in a nutshell! What can I help you with today?',
│   │   │   │   │   role='assistant',
│   │   │   │   │   stop_reason='end_of_turn',
│   │   │   │   │   tool_calls=[]
│   │   │   │   ),
│   │   │   │   session_id='abd4afea-4324-43f4-9513-cfe3970d92e8',
│   │   │   │   started_at=datetime.datetime(2025, 4, 3, 1, 15, 14, 28722, tzinfo=TzInfo(UTC)),
│   │   │   │   steps=[
│   │   │   │   │   InferenceStep(
│   │   │   │   │   │   api_model_response=CompletionMessage(
│   │   │   │   │   │   │   content='As a conversational AI, I don\'t have a personal identity in the classical sense. I exist as a program running on computer servers, designed to process and respond to text-based inputs.\n\nI\'m an instance of a type of artificial intelligence called a "language model," which is trained on vast amounts of text data to generate human-like responses. My primary function is to understand and respond to natural language inputs, like our conversation right now.\n\nThink of me as a virtual assistant, a chatbot, or a conversational interface – I\'m here to provide information, answer questions, and engage in conversation to the best of my abilities. I don\'t have feelings, emotions, or consciousness like humans do, but I\'m designed to simulate human-like interactions to make our conversations feel more natural and helpful.\n\nSo, that\'s me in a nutshell! What can I help you with today?',
│   │   │   │   │   │   │   role='assistant',
│   │   │   │   │   │   │   stop_reason='end_of_turn',
│   │   │   │   │   │   │   tool_calls=[]
│   │   │   │   │   │   ),
│   │   │   │   │   │   step_id='69831607-fa75-424a-949b-e2049e3129d1',
│   │   │   │   │   │   step_type='inference',
│   │   │   │   │   │   turn_id='8b360202-f7cb-4786-baa9-166a1b46e2ca',
│   │   │   │   │   │   completed_at=datetime.datetime(2025, 4, 3, 1, 15, 21, 716174, tzinfo=TzInfo(UTC)),
│   │   │   │   │   │   started_at=datetime.datetime(2025, 4, 3, 1, 15, 14, 28823, tzinfo=TzInfo(UTC))
│   │   │   │   │   )
│   │   │   │   ],
│   │   │   │   turn_id='8b360202-f7cb-4786-baa9-166a1b46e2ca',
│   │   │   │   completed_at=datetime.datetime(2025, 4, 3, 1, 15, 21, 727364, tzinfo=TzInfo(UTC)),
│   │   │   │   output_attachments=[]
│   │   │   )
│   │   )
│   )
)


Streaming with print helper...
inference> Déjà vu!

As I mentioned earlier, I'm an artificial intelligence language model. I don't have a personal identity or consciousness like humans do. I exist solely to process and respond to text-based inputs, providing information and assistance on a wide range of topics.

I'm a computer program designed to simulate human-like conversations, using natural language processing (NLP) and machine learning algorithms to understand and generate responses. My purpose is to help users like you with their questions, provide information, and engage in conversation.

Think of me as a virtual companion, a helpful tool designed to make your interactions more efficient and enjoyable. I don't have personal opinions, emotions, or biases, but I'm here to provide accurate and informative responses to the best of my abilities.

So, who am I? I'm just a computer program designed to help you!

:::

4.3. RAG agent

Create a file rag_agent.py and add the following code:

from llama_stack_client import LlamaStackClient
from llama_stack_client import Agent, AgentEventLogger
from llama_stack_client.types import Document
import uuid

client = LlamaStackClient(base_url=f"http://localhost:8321")

# Create a vector database instance
embedlm = next(m for m in client.models.list() if m.model_type == "embedding")
embedding_model = embedlm.identifier
vector_db_id = f"v{uuid.uuid4().hex}"
client.vector_dbs.register(
    vector_db_id=vector_db_id,
    embedding_model=embedding_model,
)

# Create Documents
urls = [
    "memory_optimizations.rst",
    "chat.rst",
    "llama3.rst",
    "datasets.rst",
    "qat_finetune.rst",
    "lora_finetune.rst",
]
documents = [
    Document(
        document_id=f"num-{i}",
        content=f"https://raw.githubusercontent.com/pytorch/torchtune/main/docs/source/tutorials/{url}",
        mime_type="text/plain",
        metadata={},
    )
    for i, url in enumerate(urls)
]

# Insert documents
client.tool_runtime.rag_tool.insert(
    documents=documents,
    vector_db_id=vector_db_id,
    chunk_size_in_tokens=512,
)

# Get the model being served
llm = next(m for m in client.models.list() if m.model_type == "llm")
model = llm.identifier

# Create RAG agent
ragagent = Agent(
    client,
    model=model,
    instructions="You are a helpful assistant. Use the RAG tool to answer questions as needed.",
    tools=[
        {
            "name": "builtin::rag/knowledge_search",
            "args": {"vector_db_ids": [vector_db_id]},
        }
    ],
)

s_id = ragagent.create_session(session_name=f"s{uuid.uuid4().hex}")

turns = ["what is torchtune", "tell me about dora"]

for t in turns:
    print("user>", t)
    stream = ragagent.create_turn(
        messages=[{"role": "user", "content": t}], session_id=s_id, stream=True
    )
    for event in AgentEventLogger().log(stream):
        event.print()

Run the script:

python rag_agent.py

:::{dropdown} Sample output

user> what is torchtune
inference> [knowledge_search(query='TorchTune')]
tool_execution> Tool:knowledge_search Args:{'query': 'TorchTune'}
tool_execution> Tool:knowledge_search Response:[TextContentItem(text='knowledge_search tool found 5 chunks:\nBEGIN of knowledge_search tool results.\n', type='text'), TextContentItem(text='Result 1:\nDocument_id:num-1\nContent:  conversational data, :func:`~torchtune.datasets.chat_dataset` seems to be a good fit. ..., type='text'), TextContentItem(text='END of knowledge_search tool results.\n', type='text')]
inference> Here is a high-level overview of the text:

**LoRA Finetuning with PyTorch Tune**

PyTorch Tune provides a recipe for LoRA (Low-Rank Adaptation) finetuning, which is a technique to adapt pre-trained models to new tasks. The recipe uses the `lora_finetune_distributed` command.
...
Overall, DORA is a powerful reinforcement learning algorithm that can learn complex tasks from human demonstrations. However, it requires careful consideration of the challenges and limitations to achieve optimal results.

:::

Next Steps

• Go through the Getting Started Notebook
• Checkout more Notebooks on GitHub
• See References for more details about the llama CLI and Python SDK
• For example applications and more detailed tutorials, visit our llama-stack-apps repository.