Function parseMaxTokensContextOverflowError

src/services/api/withRetry.ts:593–638

(error: APIError)

}

export function parseMaxTokensContextOverflowError(error: APIError):
  | {
      inputTokens: number
      maxTokens: number
      contextLimit: number
    }
  | undefined {
  if (error.status !== 400 || !error.message) {
    return undefined
  }

  if (
    !error.message.includes(
      'input length and `max_tokens` exceed context limit',
    )
  ) {
    return undefined
  }

  // Example format: "input length and `max_tokens` exceed context limit: 188059 + 20000 > 200000"
  const regex =
    /input length and `max_tokens` exceed context limit: (\d+) \+ (\d+) > (\d+)/
  const match = error.message.match(regex)

  if (!match || match.length !== 4) {
    return undefined
  }

  if (!match[1] || !match[2] || !match[3]) {
    logError(
      new Error(
        'Unable to parse max_tokens from max_tokens exceed context limit error message',
      ),
    )
    return undefined
  }
  const inputTokens = parseInt(match[1], 10)
  const maxTokens = parseInt(match[2], 10)
  const contextLimit = parseInt(match[3], 10)

  if (isNaN(inputTokens) || isNaN(maxTokens) || isNaN(contextLimit)) {
    return undefined
  }

  return { inputTokens, maxTokens, contextLimit }
}

// TODO: Replace with a response header check once the API adds a dedicated
// header for fast-mode rejection (e.g., x-fast-mode-rejected). String-matching