Getting Started with LM Studio in R

A large language model is a program that writes text in reply to text that you give it. The text that you give it is a prompt. LM Studio is a desktop app that downloads such models and runs them on your own computer. The rlmstudio package lets you control LM Studio from R. This vignette takes you from installing LM Studio to your first replies from a model.

Install LM Studio

LM Studio comes with a command-line tool called lms. A command-line tool is a program that you run by typing commands, and the messages of the package call it the CLI. The package uses lms to start and stop parts of LM Studio. If you do not have LM Studio yet, run rlmstudio::install_lmstudio(method = "browser"). It opens the LM Studio download page in your web browser. After you install LM Studio, restart R.

Load the package and check that R can find LM Studio.

library(rlmstudio)

# TRUE if R finds the lms tool
has_lms()
#> [1] TRUE

# TRUE if the lms tool is version 0.4.0 or later
check_lms_version()
#> ✔ LM Studio CLI is using the modern architecture (0.4.0+).
#> [1] TRUE

If either call returns FALSE, install or update LM Studio before you go on.

Start the server

R talks to LM Studio through a local server. A local server is a program on your own computer that answers requests from other programs, such as R. By default, the package sends its requests to http://localhost:1234. That is an address on your own computer.

lms_server_start() starts the server. Then it waits until LM Studio answers. The wait argument sets about how many seconds it waits. If the wait runs out, the function gives a warning, and your script goes on. So call lms_server_ready() next. It returns TRUE only when LM Studio answers.

# Start the server, and wait about 30 seconds for it to answer
lms_server_start(wait = 30)
#> ✔ LM Studio server started successfully on the default port.

# TRUE if LM Studio answers
lms_server_ready()
#> [1] TRUE

Find a model

A model key is the name that you give R to choose a model, such as "google/gemma-3-1b". list_models() shows the models that LM Studio has on your computer, one row for each model. The key column holds the model key. In the type column, llm marks a large language model, the kind that you chat with. The state column says whether the model is in memory, which a later section explains.

# The models on this computer, one row each
list_models()
#>      state      type          display_name                                  key
#> 1 unloaded       llm           Gemma 4 E4B                   google/gemma-4-e4b
#> 2 unloaded       llm   Gemma 4 26B A4B QAT           google/gemma-4-26b-a4b-qat
#> 3 unloaded       llm         Qwen3 4B 2507                   qwen/qwen3-4b-2507
#> 4 unloaded       llm            Gemma 3 1B                    google/gemma-3-1b
#> 5 unloaded embedding Nomic Embed Text v1.5 text-embedding-nomic-embed-text-v1.5
#>   architecture size_gb
#> 1       gemma4    6.39
#> 2       gemma4   14.57
#> 3        qwen3    2.12
#> 4  gemma3_text    0.72
#> 5         <NA>    0.08

On a new install, you have no model to chat with yet. LM Studio comes with an embedding model, a model that turns text into numbers and does not chat. The next section downloads a model that you can chat with. This vignette uses google/gemma-3-1b, a small model. Keep its key in a variable, so that each call below can use it.

model <- "google/gemma-3-1b"

Download the model

lms_download() asks LM Studio to download a model. For a model that is already on your computer, it returns "already_downloaded". For a new model, it returns a job id, a string that names the download. Pass the job id to lms_download_status() to see the status of the download. Call lms_download_status() again until the status says that the download finished.

When the output below was made, the model was already on the computer. So the output shows the first case.

# Download the model, or find that it is already on disk
job_id <- lms_download(model)
#> ℹ Initiating download for model: "google/gemma-3-1b"...
#> ✔ Initiating download for model: "google/gemma-3-1b"... [1.1s]
#> 
#> ✔ Model "google/gemma-3-1b" is already downloaded.
job_id
#> [1] "already_downloaded"

# The status of the download
lms_download_status(job_id)
#> 
#> ── Download Job: "N/A"
#> Status: already_downloaded

Put the model in memory

Loading a model means that LM Studio reads it from disk into memory. A chat with a model that is not loaded can make LM Studio load it, but then the chat waits for the load. lms_load() loads the model before the chat.

# Read the model into memory
lms_load(model)
#> ℹ Loading model: "google/gemma-3-1b"...
#> ✔ Model "google/gemma-3-1b" loaded and verified. [7.2s]
#>

Chat with the model

lms_chat() sends one prompt to the model and returns the reply as text. The input argument holds your prompt.

A system prompt is a set of instructions that the model gets with your prompt. Use it to set the role, the tone, or the length of the reply. The system_prompt argument of lms_chat() holds it.

# Send one prompt, with a system prompt
reply <- lms_chat(
  model = model,
  input = "Say hello to a new R user.",
  system_prompt = "Answer in one short sentence."
)

# Print the text of the reply
cat(reply)
#> Hello there, welcome to the world of R!

Send several prompts in one call

A batch is a set of prompts that you send in one call, such as one prompt for each row of your data. lms_chat_batch() sends each prompt in inputs as its own request, with the same system prompt. It returns one reply for each prompt, in the order of the prompts.

questions <- c(
  "Name a fruit.",
  "Name a color.",
  "Name a planet."
)

# One reply for each prompt, in the same order
answers <- lms_chat_batch(
  model = model,
  inputs = questions,
  system_prompt = "Answer with one word."
)
answers
#> [1] "Apple \n"                                       
#> [2] "Blue \n\nLet me know if you’d like another one!"
#> [3] "Mars \n"

# Remove the spaces and line breaks around each reply
trimws(answers)
#> [1] "Apple"                                          
#> [2] "Blue \n\nLet me know if you’d like another one!"
#> [3] "Mars"

A reply can carry extra spaces or line breaks, and a model does not always follow its system prompt. So read the replies before you use them.

vignette("text-analysis") shows how to get the replies of a batch as a data frame, with one row for each prompt.

Clean up

When you are done, unload the model to free its memory, and stop the server.

# Remove the model from memory
lms_unload(model)
#> ℹ Unloading model: "google/gemma-3-1b"...
#> ✔ Model "google/gemma-3-1b" unloaded successfully. [585ms]
#> 

# Stop the local server
lms_server_stop()
#> ✔ LM Studio server stopped successfully.