lmdk 1.4.0

Language Model Development Kit.

Language Model Development Kit

What it offers:

• Simplest interface to call different Language Model APIs
• Minimal dependencies: HTTP requests only, no third party packages
• Streaming
• Comfy structured outputs via Pydantic models, only if the provider / model supports it natively
• Parallel completions
• Unified HTTP error handling
• Easy location config (for providers with multiple datacenters like AWS Bedrock, GCP Vertex and Azure)
• Model fallbacks
• Bring Your Own Key (for each provider)

What it does NOT offer:

• Tools / function calling / MCP
• Agents
• Multimodality (only text-in, text-out)
• Shady under-the-hood prompt modification (e.g. to force structured output)
• API gateways

If you are looking for a more constrained but out-of-the-box agent interface, I'd recommend pydantic-ai or haystack-ai. If you are looking to keep granular control but extend on tools or multimodality, I'd recommend litellm or leveraging the OpenAI-compatible endpoints that providers normally set up. If you want a unified a token for all providers and are willing to give away telemetry data, check Gateways like openrouter.

Install

uv add lmdk

Usage

from lmdk import complete

model = "mistral:mistral-small-2603"
# supports locations as in "vertex:gemini-2.5-flash@europe-west4"

Single prompt

response = complete(model=model, prompt="Tell me a joke")

Multi-turn conversation

messages = [
    UserMessage("My name is Alice."),
    AssistantMessage("Nice to meet you, Alice!"),
    UserMessage("What is my name?"),
]
response = complete(model=model, prompt=messages)

System prompt and generation kwargs

response = complete(
    model=model,
    prompt="Hi!",
    system_instruction="Talk like a pirate",
    generation_kwargs={"temperature": 0.9, "max_tokens": 10}
)

Streaming

token_iter = complete(model=model, prompt="Count from 1 to 5.", stream=True)

Model fallbacks

response = complete(model=["mistral:nonexistent-model", model], prompt="Hi")
# first request will raise NotFoundError bc model does not exist, second will work

Structured output

class Ingredient(BaseModel):
    name: str
    quantity: int
    unit: str = ""

class Recipe(BaseModel):
    ingredients: list[Ingredient]

response = complete(model=model, prompt="How do I make cheescake?", output_schema=Recipe)
# response.parsed will have a Recipe instance

Parallel calls

from lmdk import complete_batch

results = complete_batch(model=model, prompt_list=["Greet in english", "Saluda en espanyol."])
# results will be al list of CompletionResult

Template Rendering

from lmdk import render_template

# Render a template string with variables
result = render_template(
    template="Hello, {{ name }}!",
    name="World"
)
# Output: "Hello, World!"

# Render a template from a jinja file
result = render_template(
    path="path/to/template.jinja2",
    name="World"
)

Development

Structure

src/lmdk/
├── core.py         # Entry points: complete, complete_batch
├── datatypes.py    # Common message and response schemas
├── provider.py     # Base Provider class and registry
├── providers/      # Concrete implementations (Mistral, Vertex, etc.)
├── errors.py       # Unified HTTP and API error handling
└── utils.py        # Shared helper functions

Tooling

We use just for development tasks. Use:

• just sync: Updates lockfile and syncs environment.
• just format: Lints and formats with ruff.
• just check-types: Static analysis with ty.
• just analyze-complexity: Cyclomatic complexity checks with complexipy.
• just test: Runs pytest with 90% coverage threshold.

Contribute

1. Hooks: Install pre-commit hooks via just install-hooks. PRs will fail CI if linting/formatting is not applied.
2. Issues: Open an issue first using the default template.
3. PRs: Link your PR to the relevant issue using the PR template.

You can use just validate <model> (runs example.py) to verify which features run properly and which do not for a new provider / model. Not all of them have to pass to open a PR: some providers do not even support native structured output. Do at least the normal non-structured, non-streamed completion. The rest can raise NotImplementedError.

License

MIT