@juspay/neurolink/dist/proxy/routingPolicy.js

The pipe layer of an AI nervous system: one interface connecting provider neurons to your application, across three inference types — generate, stream and decide. `decide` returns typed, calibrated judgements from a non-generative model (~400ms, ~$0.00002

export function inferClaudeProxyModelTier(modelName) {
    const normalized = modelName.toLowerCase();
    if (normalized.includes("opus")) {
        return "opus";
    }
    if (normalized.includes("sonnet")) {
        return "sonnet";
    }
    if (normalized.includes("haiku")) {
        return "haiku";
    }
    return "other";
}
/**
 * Build a translation plan for a Claude-compatible proxy request.
 * The plan lists the primary provider followed by eligible fallback targets.
 * All configured fallback entries are always eligible — no contract-based gating.
 * An "auto-provider" entry is appended only when explicitly enabled by the
 * caller. This keeps an empty fallback chain from silently escaping to an
 * unrelated provider.
 */
export function buildProxyTranslationPlan(primary, fallbackChain, requestedModel, _parsed, allowAutoFallback = false) {
    const attempts = [
        {
            provider: primary.provider,
            model: primary.model,
            label: `${primary.provider}/${primary.model ?? "unknown"}`,
        },
    ];
    for (const fallback of fallbackChain) {
        if (fallback.provider === primary.provider &&
            fallback.model === primary.model) {
            continue;
        }
        attempts.push({
            provider: fallback.provider,
            model: fallback.model,
            ...(fallback.reasoningEffort !== undefined
                ? { reasoningEffort: fallback.reasoningEffort }
                : {}),
            label: `${fallback.provider}/${fallback.model}`,
        });
    }
    // A provider chosen by the translation layer is an explicit opt-in. It is
    // intentionally not a default when configured entries are absent or deduped.
    if (allowAutoFallback &&
        (fallbackChain.length === 0 || attempts.length === 1)) {
        attempts.push({ label: "auto-provider" });
    }
    return {
        requestedModel,
        modelTier: inferClaudeProxyModelTier(requestedModel),
        attempts,
        skipped: [],
    };
}
// ---------------------------------------------------------------------------
// Retry-after parsing helper
// ---------------------------------------------------------------------------
/**
 * Parse the retry-after header from an upstream 429 response.
 * Returns milliseconds to wait, or 0 if no valid header present.
 */
export function parseRetryAfterMs(retryAfterHeader) {
    if (!retryAfterHeader) {
        return 0;
    }
    const seconds = parseInt(retryAfterHeader, 10);
    if (!Number.isNaN(seconds)) {
        return Math.max(1, seconds) * 1000;
    }
    const date = new Date(retryAfterHeader);
    if (!Number.isNaN(date.getTime())) {
        return Math.max(1000, date.getTime() - Date.now());
    }
    return 0;
}