.hu File Syntax

.hu (human) files are plain-text prompt templates. They contain no Python -- just the text you want to send to an LLM, with optional parameter placeholders and file-context references.

Each .hu file is automatically a callable function whose name matches the filename. You call .hu functions from .lm files -- .lm files are the orchestration layer that ties everything together.

Quick example

summarize.hu

Summarize the following article: {@article.txt}
Focus on {aspect} and keep it under {max_words} words.

pipeline.lm

result = summarize(aspect="key findings", max_words=200) -> HTML
print(result)

Run with:

lamia pipeline.lm

Parameter placeholders

Use {name} to define parameters. They are auto-detected -- no declaration needed.

Write a {tone} email to {recipient} about {topic}.

When called, all parameters must be passed as keyword arguments:

write_email = draft_email(tone="formal", recipient="the team", topic="Q3 results")

Missing parameters raise an error:

draft_email() missing required keyword arguments: recipient, tone, topic

To include a literal brace in the text, double it:

The result is in the format {{key: value}}.

File context references

Use {@filename} to inject the contents of a local file into the prompt. This uses the same file-context resolution as .lm files -- fuzzy matching, absolute paths, and with files() scoping all work.

Review the code in {@main.py} and suggest improvements.
Also check {@utils.py} for any issues.

See the File Context documentation for details on search strategies and error handling.

Return types

.hu files are return-type agnostic. The return type is specified by the caller in the .lm file using the -> syntax:

# Returns validated HTML
page = generate_landing_page(product="Lamia") -> HTML

# Returns a Pydantic model extracted from HTML
quote = get_stock_data(ticker="AAPL") -> HTML[StockQuote]

# Writes output to a file
generate_docs(project="lamia") -> File(Markdown, "docs.md")

If called without a return type, the raw LLM response text is returned.

Calling conventions

• .hu functions are called from .lm files like regular functions
• All parameters must be keyword arguments
• .hu files cannot call other .hu files -- use .lm files as the glue
• Filename (without .hu extension) must be unique across the project

Standalone execution

You can run a .hu file directly from the CLI:

lamia hello.hu

This sends the prompt (with no parameters) to the default model and prints the response. Parameterized .hu files require a .lm wrapper to pass arguments.

Comparison with .lm files

Feature	.hu files	.lm files
Content	Plain text prompt	Python + Lamia syntax
Parameters	{name} placeholders	Python function arguments
Return type	Set by caller	Declared with -> Type
Python code	Not supported	Full Python support
Imports	Not needed	Implicit Lamia imports
Can call .hu	No	Yes
Can call .lm	No	Yes
Filename = function	Yes	No (uses def names)