BamlClientFinishReasonError

The BamlClientFinishReasonError class represents an error that occurs when an LLM terminates with a disallowed finish reason.

You can allow or disallow finish reasons like this:

1 client<llm> OpenAIWithFinishReasonError {
2   provider openai
3   options {
4     api_key env.OPENAI_API_KEY
5     model "gpt-4"
6     // make it very small so model will stop early
7     max_tokens 10 
8     // throws if the model returns any other finish reason
9     finish_reason_allow_list ["stop"]
10     // or allow all finish reasons except length
11     // finish_reason_deny_list ["length"]
12   }
13 }

Type Definition

1 class BamlClientFinishReasonError extends Error {
2   type: 'BamlClientFinishReasonError'
3   message: string
4   prompt: string
5   raw_output: string
6   detailed_message: string
7 }

Properties

type

'BamlClientFinishReasonError'

Literal type identifier for the error class.

message

string

Error message describing the specific finish reason that caused the termination.

prompt

string

The original prompt sent to the LLM.

raw_output

string

The partial output received from the LLM before termination.

detailed_message

string

Comprehensive error information that includes the complete history of all failed attempts when using fallback clients or retry policies. When multiple attempts are made (via fallback or retry), this field contains formatted details about each failed attempt, making it invaluable for debugging complex client configurations.

Type Guards

The error can be identified using TypeScript’s instanceof operator:

Type Check

1 if (error instanceof BamlClientFinishReasonError) {
2   // Handle finish reason error
3 }

1	client<llm> OpenAIWithFinishReasonError {
2	provider openai
3	options {
4	api_key env.OPENAI_API_KEY
5	model "gpt-4"
6	// make it very small so model will stop early
7	max_tokens 10
8	// throws if the model returns any other finish reason
9	finish_reason_allow_list ["stop"]
10	// or allow all finish reasons except length
11	// finish_reason_deny_list ["length"]
12	}
13	}

1	class BamlClientFinishReasonError extends Error {
2	type: 'BamlClientFinishReasonError'
3	message: string
4	prompt: string
5	raw_output: string
6	detailed_message: string
7	}

1	if (error instanceof BamlClientFinishReasonError) {
2	// Handle finish reason error
3	}