export const TOKENS_PER_THOUSAND = 1000; export const TOKENS_PER_MILLION = 1_000_000; export const DEFAULT_COST_DECIMAL_PLACES = 6;

export type TokenUnit = typeof TOKENS_PER_THOUSAND | typeof TOKENS_PER_MILLION;

export type Price = { amount: number; perTokens: TokenUnit; };

export type ModelPricing = { prompt: Price; completion: Price; };

export type NormalizedModelPricing = { prompt: number; completion: number; };

export type TokenUsage = { promptTokens: number; completionTokens: number; totalTokens: number; };

const PROMPT_TOKEN_KEYS = ['prompt_tokens', 'promptTokens', 'input_tokens'] as const; const COMPLETION_TOKEN_KEYS = ['completion_tokens', 'completionTokens', 'output_tokens'] as const; const MODEL_SUFFIXES = ['-latest', '-preview'] as const; const ISO_DATE_SUFFIX = /-\d{4}-\d{2}-\d{2}$/; const COMPACT_DATE_SUFFIX = /-\d{8}$/; // e.g. claude-3-5-haiku-20241022

// Pricing in USD per 1M tokens to mirror OpenAI public pricing. export const MODEL_PRICING: Record<string, ModelPricing> = { 'gpt-5.1': { prompt: { amount: 1.25, perTokens: TOKENS_PER_MILLION }, completion: { amount: 10, perTokens: TOKENS_PER_MILLION }, }, 'gpt-5-pro': { prompt: { amount: 15, perTokens: TOKENS_PER_MILLION }, completion: { amount: 120, perTokens: TOKENS_PER_MILLION }, }, 'gpt-5-mini': { prompt: { amount: 0.25, perTokens: TOKENS_PER_MILLION }, completion: { amount: 2, perTokens: TOKENS_PER_MILLION }, }, 'gpt-5-nano': { prompt: { amount: 0.05, perTokens: TOKENS_PER_MILLION }, completion: { amount: 0.4, perTokens: TOKENS_PER_MILLION }, }, 'gpt-4.1': { prompt: { amount: 2.75, perTokens: TOKENS_PER_MILLION }, completion: { amount: 11, perTokens: TOKENS_PER_MILLION }, }, 'gpt-4o': { prompt: { amount: 2.5, perTokens: TOKENS_PER_MILLION }, completion: { amount: 10, perTokens: TOKENS_PER_MILLION }, }, 'gpt-4o-mini': { prompt: { amount: 0.15, perTokens: TOKENS_PER_MILLION }, completion: { amount: 0.6, perTokens: TOKENS_PER_MILLION }, }, // gpt-4.1-nano is priced like 4o-mini; keep keyed so dated variants resolve to this entry. 'gpt-4.1-nano': { prompt: { amount: 0.15, perTokens: TOKENS_PER_MILLION }, completion: { amount: 0.6, perTokens: TOKENS_PER_MILLION }, }, 'gpt-4-turbo': { prompt: { amount: 10, perTokens: TOKENS_PER_MILLION }, completion: { amount: 30, perTokens: TOKENS_PER_MILLION }, }, 'gpt-4': { prompt: { amount: 30, perTokens: TOKENS_PER_MILLION }, completion: { amount: 60, perTokens: TOKENS_PER_MILLION }, }, 'gpt-4-0613': { prompt: { amount: 30, perTokens: TOKENS_PER_MILLION }, completion: { amount: 60, perTokens: TOKENS_PER_MILLION }, }, 'gpt-4-32k': { prompt: { amount: 60, perTokens: TOKENS_PER_MILLION }, completion: { amount: 120, perTokens: TOKENS_PER_MILLION }, }, 'gpt-3.5-turbo': { prompt: { amount: 0.5, perTokens: TOKENS_PER_MILLION }, completion: { amount: 1.5, perTokens: TOKENS_PER_MILLION }, }, 'o1-preview': { prompt: { amount: 15, perTokens: TOKENS_PER_MILLION }, completion: { amount: 60, perTokens: TOKENS_PER_MILLION }, }, o1: { prompt: { amount: 15, perTokens: TOKENS_PER_MILLION }, completion: { amount: 60, perTokens: TOKENS_PER_MILLION }, }, 'o1-mini': { prompt: { amount: 3, perTokens: TOKENS_PER_MILLION }, completion: { amount: 12, perTokens: TOKENS_PER_MILLION }, }, 'text-embedding-3-large': { prompt: { amount: 0.13, perTokens: TOKENS_PER_MILLION }, completion: { amount: 0, perTokens: TOKENS_PER_MILLION }, }, // Anthropic Claude (pricing per 1M tokens) 'claude-3-5-haiku': { prompt: { amount: 0.8, perTokens: TOKENS_PER_MILLION }, completion: { amount: 4.0, perTokens: TOKENS_PER_MILLION }, }, // Claude Haiku 4.5 (pricing per 1M tokens) // Source: https://platform.claude.com/docs/en/about-claude/pricing 'claude-haiku-4-5': { prompt: { amount: 1.0, perTokens: TOKENS_PER_MILLION }, completion: { amount: 5.0, perTokens: TOKENS_PER_MILLION }, }, // Alternate naming seen in some contexts; map to same pricing. 'claude-4-5-haiku': { prompt: { amount: 1.0, perTokens: TOKENS_PER_MILLION }, completion: { amount: 5.0, perTokens: TOKENS_PER_MILLION }, }, };

export const MODEL_ALIASES: Record<string, string> = { 'gpt-5-mini-2025-08-07': 'gpt-5-mini', 'gpt-5-nano-2025-08-07': 'gpt-5-nano', 'gpt-4o-2024-11-20': 'gpt-4o', 'gpt-4o-2024-08-06': 'gpt-4o', 'gpt-4o-2024-05-13': 'gpt-4o', 'gpt-4o-mini-2024-07-18': 'gpt-4o-mini', 'gpt-4.1-nano-2025-04-14': 'gpt-4.1-nano', 'gpt-4-turbo-2024-04-09': 'gpt-4-turbo', 'gpt-4-turbo-preview': 'gpt-4-turbo', 'gpt-3.5-turbo-0125': 'gpt-3.5-turbo', 'gpt-3.5-turbo-1106': 'gpt-3.5-turbo', 'claude-3-5-haiku-latest': 'claude-3-5-haiku', 'claude-haiku-4-5-latest': 'claude-haiku-4-5', 'claude-4-5-haiku-latest': 'claude-haiku-4-5', };

function isRecord(value: unknown): value is Record<string, unknown> { return typeof value === 'object' && value !== null; }

function coerceTokenCount(value: unknown): number | null { if (typeof value === 'number') { if (!Number.isFinite(value) || value < 0) { return null; } return value; }

if (typeof value === 'string') { const trimmed = value.trim(); if (!trimmed) { return null; } const parsed = Number(trimmed); if (!Number.isFinite(parsed) || parsed < 0) { return null; } return parsed; }

return null; }

function pickTokenCount(record: Record<string, unknown>, keys: readonly string[]): number { for (const key of keys) { const parsed = coerceTokenCount(record[key]); if (parsed !== null) { return parsed; } } return 0; }

export type ParseUsageOptions = { allowZero?: boolean; };

export function parseUsage(usageCandidate: unknown, options: ParseUsageOptions = {}): TokenUsage | null { if (!isRecord(usageCandidate)) { return options.allowZero ? { promptTokens: 0, completionTokens: 0, totalTokens: 0 } : null; }

const promptTokens = pickTokenCount(usageCandidate, PROMPT_TOKEN_KEYS); const completionTokens = pickTokenCount(usageCandidate, COMPLETION_TOKEN_KEYS); const totalTokens = promptTokens + completionTokens;

if (!options.allowZero && totalTokens <= 0) { return null; }

return { promptTokens, completionTokens, totalTokens }; }

function isModelSuffix(model: string): boolean { return MODEL_SUFFIXES.some((suffix) => model.endsWith(suffix)); }

function stripModelSuffix(model: string): string { if (isModelSuffix(model)) { return model.replace(/-(latest|preview)$/, ''); } if (ISO_DATE_SUFFIX.test(model)) { return model.replace(ISO_DATE_SUFFIX, ''); } if (COMPACT_DATE_SUFFIX.test(model)) { return model.replace(COMPACT_DATE_SUFFIX, ''); } return model; }

export function resolveModelKey(model?: string | null): string | null { if (!model) return null; const normalized = stripModelSuffix(model); return MODEL_ALIASES[normalized] ?? normalized; }

function ratePerThousand(price: Price): number { return price.perTokens === TOKENS_PER_THOUSAND ? price.amount : (price.amount / price.perTokens) * TOKENS_PER_THOUSAND; }

const NORMALIZED_PRICING_CACHE = new Map<string, NormalizedModelPricing>();

export function getNormalizedPricing(model?: string | null): NormalizedModelPricing | null { if (!model) { return null; } const key = resolveModelKey(model); if (!key) return null;

const cached = NORMALIZED_PRICING_CACHE.get(key); if (cached) { return cached; }

const pricing = MODEL_PRICING[key]; if (!pricing) { return null; }

const normalized = { prompt: ratePerThousand(pricing.prompt), completion: ratePerThousand(pricing.completion), }; NORMALIZED_PRICING_CACHE.set(key, normalized); return normalized; }

export function calculateCost(usage: TokenUsage, pricing: NormalizedModelPricing): number { const promptCost = (usage.promptTokens / TOKENS_PER_THOUSAND) * pricing.prompt; const completionCost = (usage.completionTokens / TOKENS_PER_THOUSAND) * pricing.completion; return promptCost + completionCost; }

export type EstimateCostOptions = { fallbackPricing?: NormalizedModelPricing | null; decimalPlaces?: number; };

export function estimateCostUsd( model: string | undefined | null, usage: TokenUsage, options: EstimateCostOptions = {} ): number | null { const pricing = getNormalizedPricing(model) ?? options.fallbackPricing; if (!pricing) { return null; }

const cost = calculateCost(usage, pricing); if (!Number.isFinite(cost)) { return null; }

const decimalPlaces = options.decimalPlaces ?? DEFAULT_COST_DECIMAL_PLACES; return Number(cost.toFixed(decimalPlaces)); }