Function consumeCreditsForMessage

web/src/llm-api/helpers.ts:115–221

(params: {
  messageId: string
  userId: string
  stripeCustomerId?: string | null
  agentId: string
  clientId: string | null
  clientRequestId: string | null
  startTime: Date
  model: string
  reasoningText: string
  responseText: string
  usageData: UsageData
  byok: boolean
  logger: Logger
  costMode?: string
  ttftMs?: number | null
})

}

export async function consumeCreditsForMessage(params: {
  messageId: string
  userId: string
  stripeCustomerId?: string | null
  agentId: string
  clientId: string | null
  clientRequestId: string | null
  startTime: Date
  model: string
  reasoningText: string
  responseText: string
  usageData: UsageData
  byok: boolean
  logger: Logger
  costMode?: string
  ttftMs?: number | null
}): Promise<number> {
  const {
    messageId,
    userId,
    stripeCustomerId,
    agentId,
    clientId,
    clientRequestId,
    startTime,
    model,
    reasoningText,
    responseText,
    usageData,
    byok,
    logger,
    costMode,
    ttftMs,
  } = params

  // Calculate initial credits based on cost
  const initialCredits = Math.round(usageData.cost * 100 * (1 + PROFIT_MARGIN))

  // FREE mode: only specific agents using their expected models cost 0 credits
  // This is the strictest check - validates:
  // 1. The cost mode is 'free'
  // 2. The agent is in the allowed free-mode agents list
  // 3. The model matches what that specific agent is allowed to use
  // 4. The agent is either internal or published by 'codebuff' (prevents publisher spoofing)
  const isFreeModeAndAllowed =
    isFreeMode(costMode) && isFreeModeAllowedAgentModel(agentId, model)

  // Free tier agents (like file-picker) also don't charge credits for small requests
  // This is separate from FREE mode and helps with BYOK users
  // Also validates publisher to prevent spoofing attacks
  const isFreeAgentSmallRequest = isFreeAgent(agentId) && initialCredits < 5

  const credits =
    isFreeModeAndAllowed || isFreeAgentSmallRequest ? 0 : initialCredits

  if (isFreeModeAndAllowed) {
    await recordMessageWithoutBilling({
      messageId,