What causes "text is required" in BoundaryML/baml?

Pass a "text" keyword argument with the string to parse

text is required

Error message

text is required

What it means

FFI argument validation for the parse entry point: the kwargs map carried no 'text' entry. The parse function's entire input is the text to parse, so a missing key (empty or malformed argument buffer) is rejected before any parsing runs. A present-but-non-string 'text' is a sibling error ('text is not a string').

Source

Thrown at engine/language_client_cffi/src/ffi/functions.rs:173

    let BamlFunctionArguments {
        kwargs,
        client_registry,
        env_vars,
        collectors: _,
        type_builder,
        tags: _,
    } = BamlFunctionArguments::from_c_buffer(encoded_args, length)?;

    let ctx = runtime.create_ctx_manager(BamlValue::String("cffi".to_string()), None);
    let text = match kwargs.get("text") {
        Some(t) => match t.as_str() {
            Some(s) => s.to_string(),
            None => {
                return Err(anyhow::anyhow!("text is not a string"));
            }
        },
        None => {
            return Err(anyhow::anyhow!("text is required"));
        }
    };
    let allow_stream_types = match kwargs.get("stream") {
        Some(s) => match s.as_bool() {
            Some(b) => b,
            None => {
                return Err(anyhow::anyhow!("stream is not a boolean"));
            }
        },
        None => false,
    };

    // Spawn an async task to await the future and call the callback when done.
    // Ensure that a Tokio runtime is running in your application.
    let rt = RUNTIME.clone();
    rt.spawn(async move {
        let result = match std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| async {
            // TODO: There's a race condition bug here. Technically we should COPY the type builder, not just clone it.

View on GitHub (pinned to bd85ce9dee)

Solutions

Pass a "text" keyword argument with the string to parse
Check for typos in the argument name (exact lowercase "text")
If using a wrapper, ensure it forwards the text argument to the FFI call

Example fix

// before
baml.baml_call_function_parse(rt, "ExtractResume")  # no kwargs
// after
baml.baml_call_function_parse(rt, "ExtractResume", {"text": llm_output})

Defensive patterns

Strategy: validation

Validate before calling

if "text" not in kwargs or kwargs["text"] is None:
    raise ValueError("parse call requires a 'text' kwarg")

Type guard

def has_text(kwargs): return isinstance(kwargs.get('text'), str)

Try / catch

try:
    parsed = baml.baml_call_function_parse(rt, fn, kwargs)
except Exception as e:
    if 'text is required' in str(e):
        raise ValueError("Provide {'text': <llm output string>} to parse")
    raise

Prevention

Always include the 'text' kwarg (exact spelling) in parse calls
Centralize parse invocations in one helper that validates kwargs
Don't let generic wrappers silently drop unknown kwargs

When it happens

Trigger: Invoking the parse FFI entry point without including the "text" key in the kwargs map, e.g. misspelling it as txt or Text.

Common situations: Argument name typos, refactors that renamed the variable but not the kwarg key, or calling parse through a generic wrapper that drops unknown kwargs.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/dbb0b6817078d638. Report an issue: GitHub.