BoundaryML/baml · warning · BamlAbortError

BamlAbortError: Operation was aborted: {msg}

Error message

BamlAbortError: Operation was aborted: {msg}

What it means

BamlAbortError indicates the LLM call was cancelled: from_anyhow_error maps LLMResponse::Cancelled to this message. It signals the request was aborted (by the caller or the runtime) rather than failing at the provider.

Source

Thrown at engine/language_client_typescript/src/errors.rs:128

                        failed.client.as_str(),
                        failed.message.as_str(),
                        &failed.code,
                        None,
                        failed.raw_response.as_deref(),
                    )
                }
            },
            LLMResponse::UserFailure(msg) => napi::Error::new(
                napi::Status::GenericFailure,
                format!("BamlError: BamlInvalidArgumentError: {msg}"),
            ),
            LLMResponse::InternalFailure(_) => napi::Error::new(
                napi::Status::GenericFailure,
                format!(
                    "BamlError: BamlClientError: Something went wrong with the LLM client: {err}"
                ),
            ),
            LLMResponse::Cancelled(msg) => napi::Error::new(
                napi::Status::GenericFailure,
                format!("BamlAbortError: Operation was aborted: {msg}"),
            ),
        }
    } else {
        napi::Error::new(napi::Status::GenericFailure, format!("BamlError: {err:?}"))
    }
}

fn throw_baml_validation_error(
    prompt: &str,
    raw_output: &str,
    message: &str,
    detailed_message: Option<&str>,
) -> napi::Error {
    let error_json = serde_json::json!({
        "type": "BamlValidationError",
        "prompt": prompt,

View on GitHub (pinned to bd85ce9dee)

Solutions

1. Check whether your own code (AbortController, request cancellation) triggered the abort
2. If the abort is unexpected, review timeout/shutdown handling around the BAML call
3. Re-run the request; aborted calls are safe to retry
4. If aborts are legitimate, catch BamlAbortError and treat it as a user-initiated cancellation

Example fix

// before
const result = await b.MyFunction(args); // caller abort propagates as thrown error
// after
try {
  const result = await b.MyFunction(args);
} catch (e) {
  if (String(e).startsWith('BamlAbortError')) return null; // treat as cancellation
  throw e;
}

// ensure the AbortSignal is still alive before the call
if (signal?.aborted) return null;

const isAbortError = (e: unknown): boolean => String(e).startsWith('BamlAbortError');

try {
  const result = await b.MyFunction(args, { abortSignal });
} catch (e) {
  if (isAbortError(e)) return null; // user cancellation, not a failure
  throw e;
}

When it happens

Trigger: Aborting an in-flight generated-function call (AbortSignal / cancellation token), dropping the awaiting task, or the runtime cancelling the request so the driver returns LLMResponse::Cancelled.

Common situations: Users cancel a request in the UI and the app propagates the abort; request timeouts implemented via AbortController; server shutdown mid-call.

Understand the failure class

Background: Request timed out: what client-side request timeouts mean across libraries (Request timed out, TIMED_OUT, APITimeoutError) — this error's family across 39 libraries.

Related errors

• AbortError: {detailed_message}
• Operation was aborted
• {self}\n\nDetailed message: {detailed_message}
• Operation cancelled: {message}
• AbortError: {detailed_message}

AI-assisted analysis of BoundaryML/baml@bd85ce9dee (2026-09-12). Data as JSON: /api/errors/221b3482ef34b65d. Report an issue: GitHub.