Files
OmniRoute/open-sse/services/combo.ts
2026-05-08 17:35:49 -03:00

2203 lines
76 KiB
TypeScript

/**
* Shared combo (model combo) handling with fallback support
* Supports: priority, weighted, round-robin, random, least-used, cost-optimized,
* strict-random, auto, fill-first, p2c, lkgp, context-optimized, and context-relay strategies
*/
import {
checkFallbackError,
formatRetryAfter,
getRuntimeProviderProfile,
recordProviderFailure,
isProviderFailureCode,
} from "./accountFallback.ts";
import { errorResponse, unavailableResponse } from "../utils/error.ts";
import { recordComboIntent, recordComboRequest, getComboMetrics } from "./comboMetrics.ts";
import { resolveComboConfig, getDefaultComboConfig } from "./comboConfig.ts";
import { maybeGenerateHandoff, resolveContextRelayConfig } from "./contextHandoff.ts";
import { fetchCodexQuota } from "./codexQuotaFetcher.ts";
import * as semaphore from "./rateLimitSemaphore.ts";
import { getCircuitBreaker } from "../../src/shared/utils/circuitBreaker";
import { fisherYatesShuffle, getNextFromDeck } from "../../src/shared/utils/shuffleDeck";
import { parseModel } from "./model.ts";
import { applyComboAgentMiddleware, injectModelTag } from "./comboAgentMiddleware.ts";
import { classifyWithConfig, DEFAULT_INTENT_CONFIG } from "./intentClassifier.ts";
import { selectProvider as selectAutoProvider } from "./autoCombo/engine.ts";
import { selectWithStrategy } from "./autoCombo/routerStrategy.ts";
import { getTaskFitness } from "./autoCombo/taskFitness.ts";
import {
calculateFactors,
calculateScore,
DEFAULT_WEIGHTS,
type ProviderCandidate,
type ScoringWeights,
} from "./autoCombo/scoring.ts";
import { supportsToolCalling } from "./modelCapabilities.ts";
import { getSessionConnection } from "./sessionManager.ts";
import { generateRoutingHints } from "./manifestAdapter";
import type { RoutingHint } from "./manifestAdapter";
import { getModelContextLimit } from "../../src/lib/modelCapabilities";
import { getProviderConnections } from "../../src/lib/db/providers";
import {
getComboModelString,
getComboStepTarget,
getComboStepWeight,
normalizeComboStep,
} from "../../src/lib/combos/steps.ts";
import {
getConnectionRoutingTags,
matchesRoutingTags,
resolveRequestRoutingTags,
type RoutingTagMatchMode,
} from "../../src/domain/tagRouter.ts";
import { normalizeRoutingStrategy } from "../../src/shared/constants/routingStrategies.ts";
// Status codes that should mark round-robin target semaphores as cooling down.
const TRANSIENT_FOR_SEMAPHORE = [429, 502, 503, 504];
// Patterns that signal all accounts for a provider are rate-limited / exhausted.
// Used to detect 503 responses from handleNoCredentials so combo can fallback.
const ALL_ACCOUNTS_RATE_LIMITED_PATTERNS = [/unavailable/i, /service temporarily unavailable/i];
function isAllAccountsRateLimitedResponse(
status: number,
contentType: string | null,
errorText: string
): boolean {
if (status !== 503) return false;
if (!contentType?.includes("application/json")) return false;
return ALL_ACCOUNTS_RATE_LIMITED_PATTERNS.some((p) => p.test(errorText));
}
const MAX_COMBO_DEPTH = 3;
const MAX_FALLBACK_WAIT_MS = 5000;
const MAX_GLOBAL_ATTEMPTS = 30;
function comboModelNotFoundResponse(message: string) {
return errorResponse(404, message);
}
// Bootstrap defaults from ClawRouter benchmark (used when no local latency history exists yet)
const DEFAULT_MODEL_P95_MS = {
"grok-4-fast-non-reasoning": 1143,
"grok-4-1-fast-non-reasoning": 1244,
"gemini-2.5-flash": 1238,
"kimi-k2.5": 1646,
"gpt-4o-mini": 2764,
"claude-sonnet-4.6": 4000,
"claude-opus-4.6": 6000,
"deepseek-chat": 2000,
};
const MIN_HISTORY_SAMPLES = 10;
export type ResolvedComboTarget = {
kind: "model";
stepId: string;
executionKey: string;
modelStr: string;
provider: string;
providerId: string | null;
connectionId: string | null;
allowedConnectionIds?: string[] | null;
weight: number;
label: string | null;
};
type ComboRuntimeStep =
| ResolvedComboTarget
| {
kind: "combo-ref";
stepId: string;
executionKey: string;
comboName: string;
weight: number;
label: string | null;
};
function isRecord(value): value is Record<string, unknown> {
return !!value && typeof value === "object" && !Array.isArray(value);
}
function toTrimmedString(value): string | null {
return typeof value === "string" && value.trim().length > 0 ? value.trim() : null;
}
/**
* Validate that a successful (HTTP 200) non-streaming response actually contains
* meaningful content. Returns { valid: true } or { valid: false, reason }.
*
* Only inspects non-streaming JSON responses — streaming responses are passed through
* because buffering the full stream would defeat the purpose of streaming.
*
* Checks:
* 1. Body is valid JSON
* 2. Has at least one choice with non-empty content or tool_calls
*/
export async function validateResponseQuality(
response: Response,
isStreaming: boolean,
log: { warn?: (...args: unknown[]) => void }
): Promise<{ valid: boolean; reason?: string; clonedResponse?: Response }> {
if (isStreaming) return { valid: true };
const contentType = response.headers.get("content-type") || "";
if (!contentType.includes("application/json") && !contentType.includes("text/")) {
return { valid: true };
}
let cloned: Response;
try {
cloned = response.clone();
} catch {
return { valid: true };
}
let text: string;
try {
text = await cloned.text();
} catch {
return { valid: true };
}
if (!text || text.trim().length === 0) {
return { valid: false, reason: "empty response body" };
}
let json: Record<string, unknown>;
try {
json = JSON.parse(text);
} catch {
if (text.startsWith("data:") || text.startsWith("event:")) return { valid: true };
return { valid: false, reason: "response is not valid JSON" };
}
const choices = json?.choices;
if (!Array.isArray(choices) || choices.length === 0) {
if (json?.output || json?.result || json?.data || json?.response) return { valid: true };
if (json?.error) {
const err = json.error as Record<string, unknown>;
return {
valid: false,
reason: `upstream error in 200 body: ${err?.message || JSON.stringify(json.error).substring(0, 200)}`,
};
}
return { valid: true };
}
const firstChoice = choices[0];
const message = firstChoice?.message || firstChoice?.delta;
if (!message) {
return { valid: false, reason: "choice has no message object" };
}
const content = message.content;
const toolCalls = message.tool_calls;
const hasContent = content !== null && content !== undefined && content !== "";
const hasToolCalls = Array.isArray(toolCalls) && toolCalls.length > 0;
if (!hasContent && !hasToolCalls) {
return { valid: false, reason: "empty content and no tool_calls in response" };
}
return {
valid: true,
clonedResponse: new Response(text, {
status: response.status,
statusText: response.statusText,
headers: response.headers,
}),
};
}
// In-memory atomic counter per combo for round-robin distribution
// Resets on server restart (by design — no stale state)
const rrCounters = new Map();
/**
* Normalize a model entry to { model, weight }
* Supports both legacy string format and new object format
*/
function normalizeModelEntry(entry) {
return {
model: getComboStepTarget(entry) || "",
weight: getComboStepWeight(entry),
};
}
function getTargetProvider(modelStr: string, providerId?: string | null): string {
const parsed = parseModel(modelStr);
return providerId || parsed.provider || parsed.providerAlias || "unknown";
}
function isStreamReadinessTimeoutErrorBody(errorBody: unknown): boolean {
if (!errorBody || typeof errorBody !== "object") return false;
const error = (errorBody as Record<string, unknown>).error;
if (!error || typeof error !== "object") return false;
return (error as Record<string, unknown>).code === "STREAM_READINESS_TIMEOUT";
}
function toRecordedTarget(target: ResolvedComboTarget) {
return {
executionKey: target.executionKey,
stepId: target.stepId,
provider: target.provider,
providerId: target.providerId,
connectionId: target.connectionId,
label: target.label,
};
}
function buildExecutionKey(path: string[], stepId: string): string {
return [...path, stepId].join(">");
}
function normalizeRuntimeStep(entry, comboName, index, allCombos, path = []) {
const step = normalizeComboStep(entry, {
comboName,
index,
allCombos,
});
if (!step) return null;
const executionKey = buildExecutionKey(path, step.id);
const label = typeof step.label === "string" ? step.label : null;
const weight = step.weight || 0;
if (step.kind === "combo-ref") {
return {
kind: "combo-ref",
stepId: step.id,
executionKey,
comboName: step.comboName,
weight,
label,
};
}
const modelStr = getComboModelString(step);
if (!modelStr) return null;
return {
kind: "model",
stepId: step.id,
executionKey,
modelStr,
provider: getTargetProvider(modelStr, step.providerId),
providerId: step.providerId || null,
connectionId: step.connectionId || null,
weight,
label,
} satisfies ResolvedComboTarget;
}
function getDirectComboTargets(combo) {
return getOrderedTopLevelRuntimeSteps(combo, null).filter(
(entry): entry is ResolvedComboTarget => entry?.kind === "model"
);
}
function getTopLevelRuntimeSteps(combo, allCombos, path = []) {
return (combo.models || [])
.map((entry, index) => normalizeRuntimeStep(entry, combo.name, index, allCombos, path))
.filter((entry): entry is ComboRuntimeStep => entry !== null);
}
function getCompositeTierStepOrder(combo): string[] {
const compositeTiers = isRecord(combo?.config) ? combo.config.compositeTiers : null;
if (!isRecord(compositeTiers)) return [];
const defaultTier = toTrimmedString(compositeTiers.defaultTier);
const tiers = isRecord(compositeTiers.tiers) ? compositeTiers.tiers : null;
if (!defaultTier || !tiers) return [];
const orderedStepIds: string[] = [];
const visitedTiers = new Set<string>();
const seenStepIds = new Set<string>();
const tierEntries = new Map(
Object.entries(tiers)
.map(([tierName, rawTier]) => {
if (!isRecord(rawTier)) return null;
const normalizedTierName = toTrimmedString(tierName);
const stepId = toTrimmedString(rawTier.stepId);
const fallbackTier = toTrimmedString(rawTier.fallbackTier);
if (!normalizedTierName || !stepId) return null;
return [normalizedTierName, { stepId, fallbackTier }] as const;
})
.filter(Boolean)
);
let currentTier = defaultTier;
while (currentTier && tierEntries.has(currentTier) && !visitedTiers.has(currentTier)) {
visitedTiers.add(currentTier);
const entry = tierEntries.get(currentTier);
if (!entry) break;
if (!seenStepIds.has(entry.stepId)) {
orderedStepIds.push(entry.stepId);
seenStepIds.add(entry.stepId);
}
currentTier = entry.fallbackTier;
}
for (const entry of tierEntries.values()) {
if (!seenStepIds.has(entry.stepId)) {
orderedStepIds.push(entry.stepId);
seenStepIds.add(entry.stepId);
}
}
return orderedStepIds;
}
function hasCompositeTierRuntimeOrder(combo): boolean {
return getCompositeTierStepOrder(combo).length > 0;
}
function orderRuntimeStepsByCompositeTiers(steps: ComboRuntimeStep[], combo): ComboRuntimeStep[] {
const orderedStepIds = getCompositeTierStepOrder(combo);
if (orderedStepIds.length === 0) return steps;
const byStepId = new Map(steps.map((step) => [step.stepId, step]));
const seen = new Set<string>();
const ordered: ComboRuntimeStep[] = [];
for (const stepId of orderedStepIds) {
const step = byStepId.get(stepId);
if (!step || seen.has(step.stepId)) continue;
ordered.push(step);
seen.add(step.stepId);
}
for (const step of steps) {
if (seen.has(step.stepId)) continue;
ordered.push(step);
seen.add(step.stepId);
}
return ordered;
}
function getOrderedTopLevelRuntimeSteps(combo, allCombos, path = []) {
return orderRuntimeStepsByCompositeTiers(getTopLevelRuntimeSteps(combo, allCombos, path), combo);
}
function expandRuntimeStep(step, allCombos, visited = new Set(), depth = 0, path = []) {
if (step.kind === "model") return [step];
if (depth > MAX_COMBO_DEPTH) return [];
const combos = Array.isArray(allCombos) ? allCombos : allCombos?.combos || [];
const nestedCombo = combos.find((combo) => combo.name === step.comboName);
if (!nestedCombo || visited.has(step.comboName)) return [];
return resolveNestedComboTargets(nestedCombo, combos, new Set(visited), depth + 1, [
...path,
step.stepId,
]);
}
export function resolveNestedComboTargets(
combo,
allCombos,
visited = new Set(),
depth = 0,
path = []
) {
const directTargets = (combo.models || [])
.map((entry, index) => normalizeRuntimeStep(entry, combo.name, index, null, path))
.filter((entry): entry is ResolvedComboTarget => entry?.kind === "model");
if (depth > MAX_COMBO_DEPTH) return directTargets;
if (visited.has(combo.name)) return [];
visited.add(combo.name);
const runtimeSteps = getOrderedTopLevelRuntimeSteps(combo, allCombos, path);
const resolved: ResolvedComboTarget[] = [];
for (const step of runtimeSteps) {
if (step.kind === "combo-ref") {
resolved.push(...expandRuntimeStep(step, allCombos, new Set(visited), depth, path));
continue;
}
resolved.push(step);
}
return resolved;
}
/**
* Get combo models from combos data (for open-sse standalone use)
* @param {string} modelStr - Model string to check
* @param {Array|Object} combosData - Array of combos or object with combos
* @returns {Object|null} Full combo object or null if not a combo
*/
export function getComboFromData(modelStr, combosData) {
const combos = Array.isArray(combosData) ? combosData : combosData?.combos || [];
const combo = combos.find((c) => c.name === modelStr);
if (combo?.models && combo.models.length > 0) {
return combo;
}
return null;
}
/**
* Legacy: Get combo models as string array (backward compat)
*/
export function getComboModelsFromData(modelStr, combosData) {
const combo = getComboFromData(modelStr, combosData);
if (!combo) return null;
return combo.models.map((m) => normalizeModelEntry(m).model);
}
/**
* Validate combo DAG — detect circular references and enforce max depth
* @param {string} comboName - Name of the combo to validate
* @param {Array} allCombos - All combos in the system
* @param {Set} [visited] - Set of already visited combo names (for cycle detection)
* @param {number} [depth] - Current depth level
* @throws {Error} If circular reference or max depth exceeded
*/
export function validateComboDAG(comboName, allCombos, visited = new Set(), depth = 0) {
if (depth > MAX_COMBO_DEPTH) {
throw new Error(`Max combo nesting depth (${MAX_COMBO_DEPTH}) exceeded at "${comboName}"`);
}
if (visited.has(comboName)) {
throw new Error(`Circular combo reference detected: ${comboName}`);
}
visited.add(comboName);
const combos = Array.isArray(allCombos) ? allCombos : allCombos?.combos || [];
const combo = combos.find((c) => c.name === comboName);
if (!combo?.models) return;
for (const entry of combo.models) {
const modelName = normalizeModelEntry(entry).model;
// Check if this model name is itself a combo (not a provider/model pattern)
const nestedCombo = combos.find((c) => c.name === modelName);
if (nestedCombo) {
validateComboDAG(modelName, combos, new Set(visited), depth + 1);
}
}
}
/**
* Resolve nested combos by expanding inline to a flat model list
* Respects max depth and detects cycles
* @param {Object} combo - The combo object
* @param {Array} allCombos - All combos in the system
* @param {Set} [visited] - For cycle detection
* @param {number} [depth] - Current depth
* @returns {Array} Flat array of model strings
*/
export function resolveNestedComboModels(combo, allCombos, visited = new Set(), depth = 0) {
if (depth > MAX_COMBO_DEPTH) return combo.models.map((m) => normalizeModelEntry(m).model);
if (visited.has(combo.name)) return []; // cycle safety
visited.add(combo.name);
const combos = Array.isArray(allCombos) ? allCombos : allCombos?.combos || [];
const resolved = [];
for (const entry of combo.models || []) {
const modelName = normalizeModelEntry(entry).model;
const nestedCombo = combos.find((c) => c.name === modelName);
if (nestedCombo) {
// Recursively expand the nested combo
const nested = resolveNestedComboModels(nestedCombo, combos, new Set(visited), depth + 1);
resolved.push(...nested);
} else {
resolved.push(modelName);
}
}
return resolved;
}
function selectWeightedTarget<T extends { weight?: number }>(targets: T[]) {
if (targets.length === 0) return null;
const totalWeight = targets.reduce((sum, target) => sum + (target.weight || 0), 0);
if (totalWeight <= 0) {
return targets[Math.floor(Math.random() * targets.length)];
}
let random = Math.random() * totalWeight;
for (const target of targets) {
random -= target.weight || 0;
if (random <= 0) return target;
}
return targets.at(-1);
}
function orderTargetsForWeightedFallback<T extends { executionKey: string; weight: number }>(
targets: T[],
selectedExecutionKey: string,
preserveExistingOrder = false
) {
const selected = targets.find((target) => target.executionKey === selectedExecutionKey);
const rest = targets.filter((target) => target.executionKey !== selectedExecutionKey);
if (!preserveExistingOrder) {
rest.sort((a, b) => b.weight - a.weight);
}
return [selected, ...rest].filter(Boolean);
}
// shuffleArray and getNextModelFromDeck moved to src/shared/utils/shuffleDeck.ts
// combo.ts now uses the shared, mutex-protected getNextFromDeck with "combo:" namespace.
/**
* Sort models by pricing (cheapest first) for cost-optimized strategy
* @param {Array<string>} models - Model strings in "provider/model" format
* @returns {Promise<Array<string>>} Sorted model strings
*/
async function sortModelsByCost(models) {
try {
const { getPricingForModel } = await import("../../src/lib/localDb");
const withCost = await Promise.all(
models.map(async (modelStr) => {
const parsed = parseModel(modelStr);
const provider = parsed.provider || parsed.providerAlias || "unknown";
const model = parsed.model || modelStr;
try {
const pricing = await getPricingForModel(provider, model);
return { modelStr, cost: pricing?.input ?? Infinity };
} catch {
return { modelStr, cost: Infinity };
}
})
);
withCost.sort((a, b) => a.cost - b.cost);
return withCost.map((e) => e.modelStr);
} catch {
// If pricing lookup fails entirely, return original order
return models;
}
}
async function sortTargetsByCost(targets: ResolvedComboTarget[]) {
const orderedModels = await sortModelsByCost(targets.map((target) => target.modelStr));
const byModel = new Map<string, ResolvedComboTarget[]>();
for (const target of targets) {
const queue = byModel.get(target.modelStr) || [];
queue.push(target);
byModel.set(target.modelStr, queue);
}
return orderedModels
.map((modelStr) => {
const queue = byModel.get(modelStr);
return queue?.shift() || null;
})
.filter((target): target is ResolvedComboTarget => target !== null);
}
/**
* Sort models by usage count (least-used first) for least-used strategy
* @param {Array<string>} models - Model strings
* @param {string} comboName - Combo name for metrics lookup
* @returns {Array<string>} Sorted model strings
*/
function sortModelsByUsage(models, comboName) {
const metrics = getComboMetrics(comboName);
if (!metrics?.byModel) return models;
const withUsage = models.map((modelStr) => ({
modelStr,
requests: metrics.byModel[modelStr]?.requests ?? 0,
}));
withUsage.sort((a, b) => a.requests - b.requests);
return withUsage.map((e) => e.modelStr);
}
function sortTargetsByUsage(targets: ResolvedComboTarget[], comboName: string) {
const orderedModels = sortModelsByUsage(
targets.map((target) => target.modelStr),
comboName
);
const byModel = new Map<string, ResolvedComboTarget[]>();
for (const target of targets) {
const queue = byModel.get(target.modelStr) || [];
queue.push(target);
byModel.set(target.modelStr, queue);
}
return orderedModels
.map((modelStr) => {
const queue = byModel.get(modelStr);
return queue?.shift() || null;
})
.filter((target): target is ResolvedComboTarget => target !== null);
}
/**
* Sort models by context window size (largest first) for context-optimized strategy.
* Uses models.dev synced capabilities to get context limits.
* @param {Array<string>} models - Model strings in "provider/model" format
* @returns {Array<string>} Sorted model strings (largest context first)
*/
function sortModelsByContextSize(models) {
const withContext = models.map((modelStr) => {
return { modelStr, context: getModelContextLimitForModelString(modelStr) ?? 0 };
});
withContext.sort((a, b) => b.context - a.context);
return withContext.map((e) => e.modelStr);
}
function getModelContextLimitForModelString(modelStr: string) {
const parsed = parseModel(modelStr);
const provider = parsed.provider || parsed.providerAlias || "unknown";
const model = parsed.model || modelStr;
return getModelContextLimit(provider, model);
}
function sortTargetsByContextSize(targets: ResolvedComboTarget[]) {
const hasKnownContext = targets.some(
(target) => getModelContextLimitForModelString(target.modelStr) != null
);
if (!hasKnownContext) return targets;
const orderedModels = sortModelsByContextSize(targets.map((target) => target.modelStr));
const byModel = new Map<string, ResolvedComboTarget[]>();
for (const target of targets) {
const queue = byModel.get(target.modelStr) || [];
queue.push(target);
byModel.set(target.modelStr, queue);
}
return orderedModels
.map((modelStr) => {
const queue = byModel.get(modelStr);
return queue?.shift() || null;
})
.filter((target): target is ResolvedComboTarget => target !== null);
}
function getP2CTargetScore(
target: ResolvedComboTarget,
metrics: ReturnType<typeof getComboMetrics>
): number {
const breakerState = getCircuitBreaker(target.provider)?.getStatus?.()?.state;
if (breakerState === "OPEN") return -Infinity;
const modelMetric = metrics?.byModel?.[target.modelStr] || null;
const successRate = Number(modelMetric?.successRate);
const avgLatency = Number(modelMetric?.avgLatencyMs);
const successScore = Number.isFinite(successRate) ? successRate / 100 : 0.5;
const latencyScore =
Number.isFinite(avgLatency) && avgLatency > 0 ? 1 / Math.log10(avgLatency + 10) : 0.25;
const breakerPenalty = breakerState === "HALF_OPEN" ? 0.25 : 0;
return successScore + latencyScore - breakerPenalty;
}
function orderTargetsByPowerOfTwoChoices(targets: ResolvedComboTarget[], comboName: string) {
if (targets.length <= 1) return targets;
const metrics = getComboMetrics(comboName);
const firstIndex = Math.floor(Math.random() * targets.length);
let secondIndex = Math.floor(Math.random() * (targets.length - 1));
if (secondIndex >= firstIndex) secondIndex++;
const first = targets[firstIndex];
const second = targets[secondIndex];
const selectedIndex =
getP2CTargetScore(second, metrics) > getP2CTargetScore(first, metrics)
? secondIndex
: firstIndex;
return [targets[selectedIndex], ...targets.filter((_, index) => index !== selectedIndex)];
}
function toTextContent(content) {
if (typeof content === "string") return content;
if (!Array.isArray(content)) return "";
return content
.map((part) => {
if (!part || typeof part !== "object") return "";
if (typeof part.text === "string") return part.text;
return "";
})
.join("\n");
}
function extractPromptForIntent(body) {
if (!body || typeof body !== "object") return "";
const fromMessages = Array.isArray(body.messages)
? [...body.messages].reverse().find((m) => m && typeof m === "object" && m.role === "user")
: null;
if (fromMessages) return toTextContent(fromMessages.content);
if (typeof body.input === "string") return body.input;
if (Array.isArray(body.input)) {
const text = body.input
.map((item) => {
if (!item || typeof item !== "object") return "";
if (typeof item.content === "string") return item.content;
if (typeof item.text === "string") return item.text;
return "";
})
.filter(Boolean)
.join("\n");
if (text) return text;
}
if (typeof body.prompt === "string") return body.prompt;
return "";
}
function mapIntentToTaskType(intent) {
switch (intent) {
case "code":
return "coding";
case "reasoning":
return "analysis";
case "simple":
return "default";
case "medium":
default:
return "default";
}
}
function toStringArray(input) {
if (Array.isArray(input)) {
return input.map((v) => (typeof v === "string" ? v.trim() : "")).filter(Boolean);
}
if (typeof input === "string") {
return input
.split(",")
.map((v) => v.trim())
.filter(Boolean);
}
return [];
}
function getIntentConfig(settings, combo) {
const comboIntentConfig =
combo?.autoConfig?.intentConfig ||
combo?.config?.auto?.intentConfig ||
combo?.config?.intentConfig ||
{};
return {
...DEFAULT_INTENT_CONFIG,
...comboIntentConfig,
...(typeof settings?.intentDetectionEnabled === "boolean"
? { enabled: settings.intentDetectionEnabled }
: {}),
...(Number.isFinite(Number(settings?.intentSimpleMaxWords))
? { simpleMaxWords: Number(settings.intentSimpleMaxWords) }
: {}),
...(toStringArray(settings?.intentExtraCodeKeywords).length > 0
? { extraCodeKeywords: toStringArray(settings.intentExtraCodeKeywords) }
: {}),
...(toStringArray(settings?.intentExtraReasoningKeywords).length > 0
? { extraReasoningKeywords: toStringArray(settings.intentExtraReasoningKeywords) }
: {}),
...(toStringArray(settings?.intentExtraSimpleKeywords).length > 0
? { extraSimpleKeywords: toStringArray(settings.intentExtraSimpleKeywords) }
: {}),
};
}
function getBootstrapLatencyMs(modelId) {
const normalized = String(modelId || "").toLowerCase();
return DEFAULT_MODEL_P95_MS[normalized] ?? 1500;
}
async function buildAutoCandidates(targets, comboName) {
const metrics = getComboMetrics(comboName);
const { getPricingForModel } = await import("../../src/lib/localDb");
let historicalLatencyStats = {};
try {
const { getModelLatencyStats } = await import("../../src/lib/usageDb");
historicalLatencyStats = await getModelLatencyStats({
windowHours: 24,
minSamples: 3,
maxRows: 10000,
});
} catch {
// keep empty stats — auto-combo will use runtime + bootstrap signals
}
const candidates = await Promise.all(
targets.map(async (target) => {
const modelStr = target.modelStr;
const parsed = parseModel(modelStr);
const provider = target.provider || parsed.provider || parsed.providerAlias || "unknown";
const model = parsed.model || modelStr;
const historicalKey = `${provider}/${model}`;
const historicalModelMetric = historicalLatencyStats[historicalKey] || null;
const historicalTotal = Number(historicalModelMetric?.totalRequests);
const hasHistoricalSignal =
Number.isFinite(historicalTotal) && historicalTotal >= MIN_HISTORY_SAMPLES;
let costPer1MTokens = 1;
try {
const pricing = await getPricingForModel(provider, model);
const inputPrice = Number(pricing?.input);
if (Number.isFinite(inputPrice) && inputPrice >= 0) {
costPer1MTokens = inputPrice;
}
} catch {
// keep default cost
}
const modelMetric = metrics?.byModel?.[modelStr] || null;
const avgLatency = Number(modelMetric?.avgLatencyMs);
const successRate = Number(modelMetric?.successRate);
const historicalP95Latency = Number(historicalModelMetric?.p95LatencyMs);
const historicalStdDev = Number(historicalModelMetric?.latencyStdDev);
const historicalSuccessRate = Number(historicalModelMetric?.successRate); // 0..1
const p95LatencyMs = hasHistoricalSignal
? Number.isFinite(historicalP95Latency) && historicalP95Latency > 0
? historicalP95Latency
: getBootstrapLatencyMs(model)
: Number.isFinite(avgLatency) && avgLatency > 0
? avgLatency
: getBootstrapLatencyMs(model);
const errorRate = hasHistoricalSignal
? Number.isFinite(historicalSuccessRate) &&
historicalSuccessRate >= 0 &&
historicalSuccessRate <= 1
? 1 - historicalSuccessRate
: 0.05
: Number.isFinite(successRate) && successRate >= 0 && successRate <= 100
? 1 - successRate / 100
: 0.05;
const latencyStdDev =
hasHistoricalSignal && Number.isFinite(historicalStdDev) && historicalStdDev > 0
? Math.max(10, historicalStdDev)
: Math.max(10, p95LatencyMs * 0.1);
const breakerStateRaw = getCircuitBreaker(provider)?.getStatus?.()?.state;
const circuitBreakerState =
breakerStateRaw === "OPEN" || breakerStateRaw === "HALF_OPEN" ? breakerStateRaw : "CLOSED";
return {
stepId: target.stepId,
executionKey: target.executionKey,
modelStr,
provider,
model,
quotaRemaining: 100,
quotaTotal: 100,
circuitBreakerState,
costPer1MTokens,
p95LatencyMs,
latencyStdDev,
errorRate,
accountTier: "standard",
quotaResetIntervalSecs: 86400,
};
})
);
return candidates;
}
function dedupeTargetsByExecutionKey(targets: ResolvedComboTarget[]) {
const seen = new Set<string>();
return targets.filter((target) => {
if (seen.has(target.executionKey)) return false;
seen.add(target.executionKey);
return true;
});
}
async function applyRequestTagRouting(
targets: ResolvedComboTarget[],
body: Record<string, unknown> | null | undefined,
log: { info?: (...args: unknown[]) => void; warn?: (...args: unknown[]) => void }
): Promise<ResolvedComboTarget[]> {
const { tags, matchMode } = resolveRequestRoutingTags(body);
if (tags.length === 0 || targets.length === 0) {
return targets;
}
const providerIds = Array.from(
new Set(targets.map((target) => target.providerId || target.provider))
).filter(
(providerId): providerId is string => typeof providerId === "string" && providerId.length > 0
);
const providerConnections = new Map<string, Array<Record<string, unknown>>>();
await Promise.all(
providerIds.map(async (providerId) => {
try {
const connections = await getProviderConnections({ provider: providerId, isActive: true });
providerConnections.set(
providerId,
Array.isArray(connections) ? (connections as Array<Record<string, unknown>>) : []
);
} catch (error) {
log.warn?.(
"COMBO",
`Tag routing failed to load connections for provider=${providerId}: ${error instanceof Error ? error.message : String(error)}`
);
providerConnections.set(providerId, []);
}
})
);
const filteredTargets = targets.reduce<ResolvedComboTarget[]>((acc, target) => {
const providerKey = target.providerId || target.provider;
const candidateConnections =
providerConnections.get(providerKey)?.filter((connection) => {
const connectionId =
typeof connection.id === "string" && connection.id.trim().length > 0
? connection.id
: null;
if (!connectionId) return false;
if (target.connectionId) {
return connectionId === target.connectionId;
}
return true;
}) || [];
const matchedConnectionIds = candidateConnections
.filter((connection) =>
matchesRoutingTags(
getConnectionRoutingTags(connection.providerSpecificData),
tags,
matchMode
)
)
.map((connection) => connection.id)
.filter((connectionId): connectionId is string => typeof connectionId === "string");
if (matchedConnectionIds.length === 0) {
return acc;
}
if (target.connectionId) {
acc.push(target);
return acc;
}
acc.push({
...target,
allowedConnectionIds: Array.from(new Set(matchedConnectionIds)),
});
return acc;
}, []);
if (filteredTargets.length === 0) {
log.info?.(
"COMBO",
`Tag routing matched 0/${targets.length} targets for [${tags.join(", ")}] (${matchMode}); falling back to the full target set`
);
return targets;
}
log.info?.(
"COMBO",
`Tag routing matched ${filteredTargets.length}/${targets.length} targets for [${tags.join(", ")}] (${matchMode})`
);
return filteredTargets;
}
export function resolveComboTargets(combo, allCombos) {
return allCombos ? resolveNestedComboTargets(combo, allCombos) : getDirectComboTargets(combo);
}
function resolveWeightedTargets(combo, allCombos) {
const topLevelSteps = getOrderedTopLevelRuntimeSteps(combo, allCombos);
if (topLevelSteps.length === 0) {
return { orderedTargets: [], selectedStep: null };
}
const selectedStep = selectWeightedTarget(topLevelSteps);
if (!selectedStep) {
return { orderedTargets: [], selectedStep: null };
}
const orderedSteps = orderTargetsForWeightedFallback(
topLevelSteps,
selectedStep.executionKey,
hasCompositeTierRuntimeOrder(combo)
);
const expandedTargets = orderedSteps.flatMap((step) => {
if (!allCombos) {
return step.kind === "model" ? [step] : [];
}
return expandRuntimeStep(step, allCombos, new Set([combo.name]));
});
return {
orderedTargets: dedupeTargetsByExecutionKey(expandedTargets),
selectedStep,
};
}
function scoreAutoTargets(
targets: ResolvedComboTarget[],
candidates: ProviderCandidate[],
taskType: string | null,
weights: ScoringWeights
) {
const candidateByExecutionKey = new Map(
candidates.map((candidate: ProviderCandidate & { executionKey: string }) => [
candidate.executionKey,
candidate,
])
);
return targets
.map((target) => {
const candidate = candidateByExecutionKey.get(target.executionKey);
if (!candidate) return null;
const factors = calculateFactors(
candidate as ProviderCandidate,
candidates,
taskType,
getTaskFitness
);
return {
target,
score: calculateScore(factors, weights),
};
})
.filter(Boolean)
.sort((a, b) => b.score - a.score);
}
/**
* Handle combo chat with fallback.
* @param {Object} options
* @param {Object} options.body - Request body
* @param {Object} options.combo - Full combo object { name, models, strategy, config }
* @param {Function} options.handleSingleModel - Function: (body, modelStr) => Promise<Response>
* @param {Function} [options.isModelAvailable] - Optional pre-check: (modelStr) => Promise<boolean>
* @param {Object} options.log - Logger object
* @returns {Promise<Response>}
*/
/** @param {object} options */
export async function handleComboChat({
body,
combo,
handleSingleModel,
isModelAvailable,
log,
settings,
allCombos,
relayOptions,
signal,
}) {
const strategy = normalizeRoutingStrategy(combo.strategy || "priority");
const relayConfig =
strategy === "context-relay" ? resolveContextRelayConfig(relayOptions?.config || null) : null;
// ── Combo Agent Middleware (#399 + #401) ────────────────────────────────
// Apply system_message override, tool_filter_regex, and extract pinned model
// from context caching tag. These are all opt-in per combo config.
const { body: agentBody, pinnedModel } = applyComboAgentMiddleware(
body,
combo,
"" // provider/model not yet known — resolved per-model in loop
);
body = agentBody;
if (pinnedModel) {
log.info("COMBO", `[#401] Context caching: pinned model=${pinnedModel}`);
}
const clientRequestedStream = body?.stream === true;
// Wrap handleSingleModel to inject context caching tag on response (#401)
const handleSingleModelWrapped = combo.context_cache_protection
? async (b, modelStr, target) => {
const res = await handleSingleModel(b, modelStr, target);
if (!res.ok) return res;
// Non-streaming: inject tag into JSON response
// Fix #721: Use OpenAI choices format (json.choices[0].message) not json.messages
if (!b.stream) {
try {
const json = await res.clone().json();
const choice = json?.choices?.[0];
if (choice?.message) {
// Wrap single message in array for injectModelTag, then unwrap
const tagged = injectModelTag([choice.message], modelStr);
// If the message had tool_calls but no string content, injectModelTag
// appends a synthetic assistant message — use the last one
const taggedMsg = tagged.at(-1);
const updatedJson = {
...json,
choices: [{ ...choice, message: taggedMsg }, ...(json.choices?.slice(1) || [])],
};
return new Response(JSON.stringify(updatedJson), {
status: res.status,
headers: res.headers,
});
}
} catch {
/* non-JSON — skip tagging */
}
return res;
}
// Streaming (Fix #490 + #511): prepend omniModel tag into the first
// non-empty content chunk so it arrives BEFORE finish_reason:stop.
// SDKs close the connection on finish_reason, so anything sent after
// that marker is silently dropped.
if (!res.body) return res;
const tagContent = `<omniModel>${modelStr}</omniModel>`;
const encoder = new TextEncoder();
const decoder = new TextDecoder();
let tagInjected = false;
const transform = new TransformStream({
transform(chunk, controller) {
if (tagInjected) {
// Already injected — passthrough
controller.enqueue(chunk);
return;
}
const text = decoder.decode(chunk, { stream: true });
// Fix #721: Look for either non-empty content OR tool_calls in the
// SSE data. Tool-call-only responses have content:null, so we inject
// the tag when we see a finish_reason approaching, or on first content.
const contentMatch = RegExp(/"content":"([^"]+)/).exec(text);
if (contentMatch) {
// Inject tag at the beginning of the first content value
const injected = text.replace(
/"content":"([^"]+)/,
`"content":"${tagContent.replaceAll("\\", "\\\\").replaceAll('"', String.raw`\"`)}$1`
);
tagInjected = true;
controller.enqueue(encoder.encode(injected));
return;
}
// Fix #721: For tool-call-only streams, inject the tag when we see
// the finish_reason chunk (before it reaches the client SDK which
// would close the connection). This ensures the tag roundtrips
// through the conversation history even when there's no text content.
if (text.includes('"finish_reason"') && !text.includes('"finish_reason":null')) {
// Inject a content chunk with the tag just before this finish chunk
const tagChunk = `data: ${JSON.stringify({
choices: [
{
delta: { content: tagContent },
index: 0,
finish_reason: null,
},
],
})}\n\n`;
tagInjected = true;
controller.enqueue(encoder.encode(tagChunk));
controller.enqueue(chunk);
return;
}
// No content yet — passthrough
controller.enqueue(chunk);
},
flush(controller) {
// If stream ends without ever finding content (edge case),
// inject tag as a standalone chunk before the stream closes
if (!tagInjected) {
const tagChunk = `data: ${JSON.stringify({
choices: [
{
delta: { content: tagContent },
index: 0,
finish_reason: null,
},
],
})}\n\n`;
controller.enqueue(encoder.encode(tagChunk));
}
},
});
// FIX #585: Sanitize outbound stream — strip <omniModel> tags from
// visible content so they don't leak to the user. The tag is still
// present in the full response for round-trip context pinning, but
// we clean it from each SSE chunk's content field before delivery.
//
// IMPORTANT: Use a SEPARATE TextDecoder from the transform stream above.
// The transform stream's decoder accumulates UTF-8 state; reusing it here
// would corrupt multi-byte characters split across chunk boundaries.
const sanitizeDecoder = new TextDecoder();
const sanitize = new TransformStream({
transform(chunk, controller) {
const text = sanitizeDecoder.decode(chunk, { stream: true });
if (text) {
if (text.includes("<omniModel>")) {
const cleaned = text.replaceAll(
/(?:\\n|\n|\r)*<omniModel>[^<]+<\/omniModel>(?:\\n|\n|\r)*/g,
""
);
if (cleaned) controller.enqueue(encoder.encode(cleaned));
} else {
controller.enqueue(encoder.encode(text));
}
}
},
flush(controller) {
const tail = sanitizeDecoder.decode();
if (tail) {
if (tail.includes("<omniModel>")) {
const cleaned = tail.replaceAll(
/(?:\\n|\n|\r)*<omniModel>[^<]+<\/omniModel>(?:\\n|\n|\r)*/g,
""
);
if (cleaned) controller.enqueue(encoder.encode(cleaned));
} else {
controller.enqueue(encoder.encode(tail));
}
}
},
});
const transformedStream = res.body.pipeThrough(transform).pipeThrough(sanitize);
// Add model info as response header for clients that support it
const headers = new Headers(res.headers);
headers.set("X-OmniRoute-Model", modelStr);
return new Response(transformedStream, {
status: res.status,
headers,
});
}
: handleSingleModel;
// ─────────────────────────────────────────────────────────────────────────
// Route to pinned model if context caching specifies one (Fix #679)
if (pinnedModel) {
log.info(
"COMBO",
`Bypassing strategy — routing directly to pinned context model: ${pinnedModel}`
);
return handleSingleModelWrapped(body, pinnedModel);
}
// Route to round-robin handler if strategy matches
if (strategy === "round-robin") {
return handleRoundRobinCombo({
body,
combo,
handleSingleModel: handleSingleModelWrapped,
isModelAvailable,
log,
settings,
allCombos,
signal,
});
}
// Use config cascade if settings provided
const config = settings
? resolveComboConfig(combo, settings)
: { ...getDefaultComboConfig(), ...(combo.config || {}) };
const maxRetries = config.maxRetries ?? 1;
const retryDelayMs = config.retryDelayMs ?? 2000;
let orderedTargets =
strategy === "weighted"
? resolveWeightedTargets(combo, allCombos)?.orderedTargets || []
: resolveComboTargets(combo, allCombos);
orderedTargets = await applyRequestTagRouting(orderedTargets, body, log);
if (strategy === "weighted") {
log.info(
"COMBO",
`Weighted selection${allCombos ? " with nested resolution" : ""}: ${orderedTargets.length} total targets`
);
} else if (allCombos) {
log.info("COMBO", `${strategy} with nested resolution: ${orderedTargets.length} total targets`);
}
if (strategy === "auto") {
const requestHasTools = Array.isArray(body?.tools) && body.tools.length > 0;
let eligibleTargets = [...orderedTargets];
if (requestHasTools) {
const filtered = eligibleTargets.filter((target) => supportsToolCalling(target.modelStr));
if (filtered.length > 0) {
eligibleTargets = filtered;
} else {
log.warn(
"COMBO",
"Auto strategy: all candidates filtered by tool-calling policy, falling back to full pool"
);
}
}
const prompt = extractPromptForIntent(body);
const systemPrompt =
typeof combo?.system_message === "string" ? combo.system_message : undefined;
const intentConfig = getIntentConfig(settings, combo);
const intent = classifyWithConfig(prompt, intentConfig, systemPrompt);
recordComboIntent(combo.name, intent);
const taskType = mapIntentToTaskType(intent);
const autoConfigSource = combo?.autoConfig || combo?.config?.auto || combo?.config || {};
const routingStrategy =
typeof autoConfigSource.routingStrategy === "string"
? autoConfigSource.routingStrategy
: typeof autoConfigSource.strategyName === "string"
? autoConfigSource.strategyName
: "rules";
const candidatePool = Array.isArray(autoConfigSource.candidatePool)
? autoConfigSource.candidatePool
: [...new Set(eligibleTargets.map((target) => target.provider))];
const weights =
autoConfigSource.weights && typeof autoConfigSource.weights === "object"
? autoConfigSource.weights
: DEFAULT_WEIGHTS;
const explorationRate = Number.isFinite(Number(autoConfigSource.explorationRate))
? Number(autoConfigSource.explorationRate)
: 0.05;
const budgetCap = Number.isFinite(Number(autoConfigSource.budgetCap))
? Number(autoConfigSource.budgetCap)
: undefined;
const modePack =
typeof autoConfigSource.modePack === "string" ? autoConfigSource.modePack : undefined;
let lastKnownGoodProvider: string | undefined;
try {
const { getLKGP } = await import("../../src/lib/localDb");
const lkgp = await getLKGP(combo.name, combo.id || combo.name);
if (lkgp) lastKnownGoodProvider = lkgp;
} catch (err) {
log.warn("COMBO", "Failed to retrieve Last Known Good Provider. This is non-fatal.", { err });
}
const candidates = await buildAutoCandidates(eligibleTargets, combo.name);
if (candidates.length > 0) {
let selectedProvider = null;
let selectedModel = null;
let selectionReason = "";
if (routingStrategy !== "rules") {
try {
const decision = selectWithStrategy(
candidates,
{ taskType, requestHasTools, lastKnownGoodProvider },
routingStrategy
);
selectedProvider = decision.provider;
selectedModel = decision.model;
selectionReason = decision.reason;
} catch (err) {
log.warn(
"COMBO",
`Auto strategy '${routingStrategy}' failed (${err?.message || "unknown"}), falling back to rules`
);
}
}
if (!selectedProvider || !selectedModel) {
const selection = selectAutoProvider(
{
id: combo.id || combo.name,
name: combo.name,
type: "auto",
candidatePool,
weights,
modePack,
budgetCap,
explorationRate,
},
candidates,
taskType
);
selectedProvider = selection.provider;
selectedModel = selection.model;
selectionReason = `score=${selection.score.toFixed(3)}${selection.isExploration ? " (exploration)" : ""}`;
}
const scoredTargets = scoreAutoTargets(eligibleTargets, candidates, taskType, weights);
const rankedTargets = scoredTargets.map((entry) => entry.target);
const selectedTarget =
scoredTargets.find((entry) => {
const parsed = parseModel(entry.target.modelStr);
const modelId = parsed.model || entry.target.modelStr;
return entry.target.provider === selectedProvider && modelId === selectedModel;
})?.target ||
rankedTargets[0] ||
eligibleTargets[0];
orderedTargets = dedupeTargetsByExecutionKey(
[selectedTarget, ...rankedTargets, ...eligibleTargets].filter(Boolean)
);
log.info(
"COMBO",
`Auto selection: ${selectedTarget?.modelStr || `${selectedProvider}/${selectedModel}`} | intent=${intent} task=${taskType} | strategy=${routingStrategy} | ${selectionReason}`
);
} else {
log.warn("COMBO", "Auto strategy has no candidates, keeping default ordering");
}
} else if (strategy === "lkgp") {
try {
const { getLKGP } = await import("../../src/lib/localDb");
const lkgpProvider = await getLKGP(combo.name, combo.id || combo.name);
if (lkgpProvider) {
const lkgpIndex = orderedTargets.findIndex(
(target) =>
target.provider === lkgpProvider || target.modelStr.startsWith(`${lkgpProvider}/`)
);
if (lkgpIndex > 0) {
const [lkgpTarget] = orderedTargets.splice(lkgpIndex, 1);
orderedTargets.unshift(lkgpTarget);
log.info(
"COMBO",
`[LKGP] Prioritizing last known good provider ${lkgpProvider} for combo "${combo.name}"`
);
} else if (lkgpIndex === 0) {
log.debug(
"COMBO",
`[LKGP] Last known good provider ${lkgpProvider} already first for combo "${combo.name}"`
);
}
}
} catch (err) {
log.warn("COMBO", "Failed to retrieve Last Known Good Provider. This is non-fatal.", { err });
}
} else if (strategy === "strict-random") {
const selectedExecutionKey = await getNextFromDeck(
`combo:${combo.name}`,
orderedTargets.map((target) => target.executionKey)
);
const selectedTarget =
orderedTargets.find((target) => target.executionKey === selectedExecutionKey) || null;
const rest = orderedTargets.filter((target) => target.executionKey !== selectedExecutionKey);
orderedTargets = [selectedTarget, ...rest].filter(Boolean);
log.info(
"COMBO",
`Strict-random deck: ${selectedExecutionKey} selected (${orderedTargets.length} targets)`
);
} else if (strategy === "random") {
orderedTargets = fisherYatesShuffle([...orderedTargets]);
log.info("COMBO", `Random shuffle: ${orderedTargets.length} targets`);
} else if (strategy === "fill-first") {
log.info(
"COMBO",
`Fill-first ordering: preserving priority order (${orderedTargets.length} targets)`
);
} else if (strategy === "p2c") {
orderedTargets = orderTargetsByPowerOfTwoChoices(orderedTargets, combo.name);
log.info("COMBO", `Power-of-two-choices ordering: selected ${orderedTargets[0]?.modelStr}`);
} else if (strategy === "least-used") {
orderedTargets = sortTargetsByUsage(orderedTargets, combo.name);
log.info("COMBO", `Least-used ordering: ${orderedTargets[0]?.modelStr} has fewest requests`);
} else if (strategy === "cost-optimized") {
orderedTargets = await sortTargetsByCost(orderedTargets);
if (config.manifestRouting === true) {
try {
const manifestHint = generateRoutingHints(
orderedTargets.filter((t) => t.kind === "model"),
{
messages: Array.isArray(body?.messages) ? body.messages : [],
tools: body?.tools,
model: body?.model,
}
);
if (manifestHint.strategyModifier === "require-premium") {
const eligible = orderedTargets.filter(
(t) =>
t.kind !== "model" ||
manifestHint.eligibleTargets.some(
(e) => e.provider === t.provider && e.modelStr === t.modelStr
)
);
if (eligible.length > 0) orderedTargets = eligible;
}
log.debug(
{
strategyModifier: manifestHint.strategyModifier,
specificityLevel: manifestHint.specificityLevel,
score: manifestHint.specificity.score,
},
"manifest routing applied"
);
} catch (err) {
log.warn({ err }, "manifest routing failed, falling back to standard strategy");
}
}
log.info("COMBO", `Cost-optimized ordering: cheapest first (${orderedTargets[0]?.modelStr})`);
} else if (strategy === "context-optimized") {
orderedTargets = sortTargetsByContextSize(orderedTargets);
log.info("COMBO", `Context-optimized ordering: largest first (${orderedTargets[0]?.modelStr})`);
}
if (orderedTargets.length === 0) {
return comboModelNotFoundResponse("Combo has no executable targets");
}
let lastError = null;
let earliestRetryAfter = null;
let lastStatus = null;
const startTime = Date.now();
let globalAttempts = 0;
let fallbackCount = 0;
let recordedAttempts = 0;
for (let i = 0; i < orderedTargets.length; i++) {
const target = orderedTargets[i];
const modelStr = target.modelStr;
const provider = target.provider;
const profile = await getRuntimeProviderProfile(provider);
// Pre-check: skip models where all accounts are in cooldown
if (isModelAvailable) {
const available = await isModelAvailable(modelStr, target);
if (!available) {
log.info("COMBO", `Skipping ${modelStr} (all accounts in cooldown)`);
if (i > 0) fallbackCount++;
continue;
}
}
// Retry loop for transient errors
for (let retry = 0; retry <= maxRetries; retry++) {
// Fix #1681: Bail out immediately if the client has disconnected
if (signal?.aborted) {
log.info("COMBO", `Client disconnected — aborting combo loop before model ${modelStr}`);
return errorResponse(499, "Client disconnected");
}
globalAttempts++;
if (globalAttempts > MAX_GLOBAL_ATTEMPTS) {
log.warn(
"COMBO",
`Maximum combo attempts (${MAX_GLOBAL_ATTEMPTS}) exceeded across all targets and fallbacks. Terminating loop to prevent runaway background requests.`
);
return errorResponse(503, "Maximum combo retry limit reached");
}
if (retry > 0) {
log.info(
"COMBO",
`Retrying ${modelStr} in ${retryDelayMs}ms (attempt ${retry + 1}/${maxRetries + 1})`
);
await new Promise((resolve) => {
const timer = setTimeout(resolve, retryDelayMs);
signal?.addEventListener(
"abort",
() => {
clearTimeout(timer);
resolve(undefined);
},
{ once: true }
);
});
if (signal?.aborted) {
log.info("COMBO", `Client disconnected during retry delay — aborting`);
return errorResponse(499, "Client disconnected");
}
}
log.info(
"COMBO",
`Trying model ${i + 1}/${orderedTargets.length}: ${modelStr}${retry > 0 ? ` (retry ${retry})` : ""}`
);
const result = await handleSingleModelWrapped(body, modelStr, target);
// Success — validate response quality before returning
if (result.ok) {
const quality = await validateResponseQuality(result, clientRequestedStream, log);
if (!quality.valid) {
log.warn(
"COMBO",
`Model ${modelStr} returned 200 but failed quality check: ${quality.reason}`
);
recordComboRequest(combo.name, modelStr, {
success: false,
latencyMs: Date.now() - startTime,
fallbackCount,
strategy,
target: toRecordedTarget(target),
});
recordedAttempts++;
// Fix #1707: Set terminal state so the fallback doesn't emit
// misleading ALL_ACCOUNTS_INACTIVE when the real issue is quality.
lastError = `Upstream response failed quality validation: ${quality.reason}`;
if (!lastStatus) lastStatus = 502;
if (i > 0) fallbackCount++;
break; // move to next model
}
const latencyMs = Date.now() - startTime;
log.info(
"COMBO",
`Model ${modelStr} succeeded (${latencyMs}ms, ${fallbackCount} fallbacks)`
);
recordComboRequest(combo.name, modelStr, {
success: true,
latencyMs,
fallbackCount,
strategy,
target: toRecordedTarget(target),
});
recordedAttempts++;
// Context-relay intentionally splits responsibilities:
// combo.ts decides whether a successful turn should generate a handoff,
// while chat.ts injects the handoff after the real connectionId is resolved.
if (
strategy === "context-relay" &&
relayOptions?.sessionId &&
relayConfig &&
relayConfig.handoffProviders.includes(provider) &&
provider === "codex"
) {
const connectionId = getSessionConnection(relayOptions.sessionId);
if (connectionId) {
const quotaInfo = await fetchCodexQuota(connectionId).catch(() => null);
if (quotaInfo) {
const resetCandidates = [quotaInfo.window5h?.resetAt, quotaInfo.window7d?.resetAt]
.filter((value): value is string => typeof value === "string" && value.length > 0)
.sort((a, b) => a.localeCompare(b));
const handoffSourceMessages =
Array.isArray(body?.messages) && body.messages.length > 0
? body.messages
: Array.isArray(body?.input)
? body.input
: [];
maybeGenerateHandoff({
sessionId: relayOptions.sessionId,
comboName: combo.name,
connectionId,
percentUsed: quotaInfo.percentUsed,
messages: handoffSourceMessages,
model: modelStr,
expiresAt: resetCandidates[0] || null,
config: relayConfig,
handleSingleModel: handleSingleModelWrapped,
});
}
}
}
// Record last known good provider (LKGP) for this combo/model (#919)
if (provider) {
try {
const { setLKGP } = await import("../../src/lib/localDb");
await Promise.all([
setLKGP(combo.name, target.executionKey, provider),
setLKGP(combo.name, combo.id || combo.name, provider),
]);
} catch (err) {
log.warn("COMBO", "Failed to record Last Known Good Provider. This is non-fatal.", {
err,
});
}
}
return quality.clonedResponse ?? result;
}
// Extract error info from response
let errorText = result.statusText || "";
let errorBody = null;
let retryAfter = null;
try {
const cloned = result.clone();
try {
const text = await cloned.text();
if (text) {
errorText = text.substring(0, 500);
errorBody = JSON.parse(text);
errorText =
errorBody?.error?.message || errorBody?.error || errorBody?.message || errorText;
retryAfter = errorBody?.retryAfter || null;
}
} catch {
/* Clone parse failed */
}
} catch {
/* Clone failed */
}
// Track earliest retryAfter
if (
retryAfter &&
(!earliestRetryAfter || new Date(retryAfter) < new Date(earliestRetryAfter))
) {
earliestRetryAfter = retryAfter;
}
// Normalize error text
if (typeof errorText !== "string") {
try {
errorText = JSON.stringify(errorText);
} catch {
errorText = String(errorText);
}
}
const isStreamReadinessTimeout =
result.status === 504 && isStreamReadinessTimeoutErrorBody(errorBody);
// Fix #1681: Status 499 means client disconnected — stop combo loop immediately.
// There is no point trying fallback models when nobody is listening.
if (result.status === 499) {
log.info("COMBO", `Client disconnected (499) during ${modelStr} — stopping combo loop`);
recordComboRequest(combo.name, modelStr, {
success: false,
latencyMs: Date.now() - startTime,
fallbackCount,
strategy,
target: toRecordedTarget(target),
});
recordedAttempts++;
return result;
}
// Combo fallback is target-level orchestration: a non-ok target response is
// treated as local to that target and the combo continues to the next target.
// Error classification is retained only for retry/cooldown pacing; it must
// not decide whether fallback happens, including for generic 400 responses.
const { cooldownMs } = checkFallbackError(
result.status,
errorText,
0,
null,
provider,
result.headers,
profile
);
// Trigger shared provider circuit breaker for 5xx errors and connection failures
if (isProviderFailureCode(result.status)) {
recordProviderFailure(provider, log, target.connectionId, profile);
}
// Check if this is a transient error worth retrying on same model
const isTransient =
!isStreamReadinessTimeout && [408, 429, 500, 502, 503, 504].includes(result.status);
if (retry < maxRetries && isTransient) {
continue; // Retry same model
}
// Done retrying this model
recordComboRequest(combo.name, modelStr, {
success: false,
latencyMs: Date.now() - startTime,
fallbackCount,
strategy,
target: toRecordedTarget(target),
});
recordedAttempts++;
lastError = errorText || String(result.status);
if (!lastStatus) lastStatus = result.status;
if (i > 0) fallbackCount++;
log.warn("COMBO", `Model ${modelStr} failed, trying next`, { status: result.status });
const fallbackWaitMs =
retryDelayMs > 0 && cooldownMs > 0 && cooldownMs <= MAX_FALLBACK_WAIT_MS
? Math.min(cooldownMs, retryDelayMs)
: 0;
if ([502, 503, 504].includes(result.status) && fallbackWaitMs > 0) {
log.info("COMBO", `Waiting ${fallbackWaitMs}ms before fallback to next model`);
await new Promise((resolve) => {
const timer = setTimeout(resolve, fallbackWaitMs);
signal?.addEventListener(
"abort",
() => {
clearTimeout(timer);
resolve(undefined);
},
{ once: true }
);
});
if (signal?.aborted) {
log.info("COMBO", `Client disconnected during fallback wait — aborting`);
return errorResponse(499, "Client disconnected");
}
}
break; // Move to next model
}
}
// All models failed
const latencyMs = Date.now() - startTime;
if (recordedAttempts === 0) {
recordComboRequest(combo.name, null, { success: false, latencyMs, fallbackCount, strategy });
}
if (!lastStatus) {
return new Response(
JSON.stringify({
error: {
message: "Service temporarily unavailable: all upstream accounts are inactive",
type: "service_unavailable",
code: "ALL_ACCOUNTS_INACTIVE",
},
}),
{ status: 503, headers: { "Content-Type": "application/json" } }
);
}
const status = lastStatus;
const msg = lastError || "All combo models unavailable";
if (earliestRetryAfter) {
const retryHuman = formatRetryAfter(earliestRetryAfter);
log.warn("COMBO", `All models failed | ${msg} (${retryHuman})`);
return unavailableResponse(status, msg, earliestRetryAfter, retryHuman);
}
log.warn("COMBO", `All models failed | ${msg}`);
return new Response(JSON.stringify({ error: { message: msg } }), {
status,
headers: { "Content-Type": "application/json" },
});
}
/**
* Handle round-robin combo: each request goes to the next model in circular order.
* Uses semaphore-based concurrency control with queue + rate-limit awareness.
*
* Flow:
* 1. Pick target model via atomic counter (counter % models.length)
* 2. Acquire semaphore slot (may queue if at max concurrency)
* 3. Send request to target model
* 4. On 429 → mark model rate-limited, try next model in rotation
* 5. On semaphore timeout → fallback to next available model
*/
async function handleRoundRobinCombo({
body,
combo,
handleSingleModel,
isModelAvailable,
log,
settings,
allCombos,
signal,
}) {
const config = settings
? resolveComboConfig(combo, settings)
: { ...getDefaultComboConfig(), ...(combo.config || {}) };
const concurrency = config.concurrencyPerModel ?? 3;
const queueTimeout = config.queueTimeoutMs ?? 30000;
const maxRetries = config.maxRetries ?? 1;
const retryDelayMs = config.retryDelayMs ?? 2000;
const orderedTargets = resolveComboTargets(combo, allCombos);
const filteredTargets = await applyRequestTagRouting(orderedTargets, body, log);
const modelCount = filteredTargets.length;
if (modelCount === 0) {
return comboModelNotFoundResponse("Round-robin combo has no executable targets");
}
// Get and increment atomic counter
const counter = rrCounters.get(combo.name) || 0;
rrCounters.set(combo.name, counter + 1);
const startIndex = counter % modelCount;
const clientRequestedStream = body?.stream === true;
const startTime = Date.now();
let lastError = null;
let lastStatus = null;
let earliestRetryAfter = null;
let globalAttempts = 0;
let fallbackCount = 0;
let recordedAttempts = 0;
// Try each model starting from the round-robin target
for (let offset = 0; offset < modelCount; offset++) {
const modelIndex = (startIndex + offset) % modelCount;
const target = filteredTargets[modelIndex];
const modelStr = target.modelStr;
const provider = target.provider;
const profile = await getRuntimeProviderProfile(provider);
const semaphoreKey = `combo:${combo.name}:${target.executionKey}`;
// Pre-check availability
if (isModelAvailable) {
const available = await isModelAvailable(modelStr, target);
if (!available) {
log.info("COMBO-RR", `Skipping ${modelStr} (all accounts in cooldown)`);
if (offset > 0) fallbackCount++;
continue;
}
}
// Acquire semaphore slot (may wait in queue)
let release;
try {
release = await semaphore.acquire(semaphoreKey, {
maxConcurrency: concurrency,
timeoutMs: queueTimeout,
});
} catch (err) {
if (err.code === "SEMAPHORE_TIMEOUT" || err.code === "SEMAPHORE_QUEUE_FULL") {
log.warn(
"COMBO-RR",
`Semaphore ${err.code === "SEMAPHORE_QUEUE_FULL" ? "queue full" : "timeout"} for ${modelStr}, trying next model`
);
if (offset > 0) fallbackCount++;
continue;
}
throw err;
}
// Retry loop within this model
try {
for (let retry = 0; retry <= maxRetries; retry++) {
globalAttempts++;
if (globalAttempts > MAX_GLOBAL_ATTEMPTS) {
log.warn(
"COMBO-RR",
`Maximum combo attempts (${MAX_GLOBAL_ATTEMPTS}) exceeded. Terminating loop to prevent runaway requests.`
);
return errorResponse(503, "Maximum combo retry limit reached");
}
if (retry > 0) {
log.info(
"COMBO-RR",
`Retrying ${modelStr} in ${retryDelayMs}ms (attempt ${retry + 1}/${maxRetries + 1})`
);
await new Promise((r) => setTimeout(r, retryDelayMs));
}
log.info(
"COMBO-RR",
`[RR #${counter}] → ${modelStr}${offset > 0 ? ` (fallback +${offset})` : ""}${retry > 0 ? ` (retry ${retry})` : ""}`
);
const result = await handleSingleModel(body, modelStr, target);
// Success — validate response quality before returning
if (result.ok) {
const quality = await validateResponseQuality(result, clientRequestedStream, log);
if (!quality.valid) {
log.warn(
"COMBO-RR",
`${modelStr} returned 200 but failed quality check: ${quality.reason}`
);
recordComboRequest(combo.name, modelStr, {
success: false,
latencyMs: Date.now() - startTime,
fallbackCount,
strategy: "round-robin",
target: toRecordedTarget(target),
});
recordedAttempts++;
// Fix #1707: Set terminal state so the fallback doesn't emit
// misleading ALL_ACCOUNTS_INACTIVE when the real issue is quality.
lastError = `Upstream response failed quality validation: ${quality.reason}`;
if (!lastStatus) lastStatus = 502;
if (offset > 0) fallbackCount++;
break; // move to next model
}
const latencyMs = Date.now() - startTime;
log.info(
"COMBO-RR",
`${modelStr} succeeded (${latencyMs}ms, ${fallbackCount} fallbacks)`
);
recordComboRequest(combo.name, modelStr, {
success: true,
latencyMs,
fallbackCount,
strategy: "round-robin",
target: toRecordedTarget(target),
});
recordedAttempts++;
if (provider) {
try {
const { setLKGP } = await import("../../src/lib/localDb");
await Promise.all([
setLKGP(combo.name, target.executionKey, provider),
setLKGP(combo.name, combo.id || combo.name, provider),
]);
} catch (err) {
log.warn(
"COMBO-RR",
"Failed to record Last Known Good Provider. This is non-fatal.",
{
err,
}
);
}
}
return result;
}
// Extract error info
let errorText = result.statusText || "";
let retryAfter = null;
let errorBody: {
error?: { code?: string | null; message?: string | null } | string;
message?: string | null;
retryAfter?: number | string | null;
} | null = null;
try {
const cloned = result.clone();
try {
const text = await cloned.text();
if (text) {
errorText = text.substring(0, 500);
errorBody = JSON.parse(text);
errorText =
errorBody?.error?.message || errorBody?.error || errorBody?.message || errorText;
retryAfter = errorBody?.retryAfter || null;
}
} catch {
/* Clone parse failed */
}
} catch {
/* Clone failed */
}
if (result.status === 499) {
log.info(
"COMBO-RR",
`Client disconnected (499) during ${modelStr} — stopping combo loop`
);
recordComboRequest(combo.name, modelStr, {
success: false,
latencyMs: Date.now() - startTime,
fallbackCount,
strategy: "round-robin",
target: toRecordedTarget(target),
});
recordedAttempts++;
return result;
}
if (
retryAfter &&
(!earliestRetryAfter || new Date(retryAfter) < new Date(earliestRetryAfter))
) {
earliestRetryAfter = retryAfter;
}
if (typeof errorText !== "string") {
try {
errorText = JSON.stringify(errorText);
} catch {
errorText = String(errorText);
}
}
const isStreamReadinessTimeout =
result.status === 504 && isStreamReadinessTimeoutErrorBody(errorBody);
// Round-robin uses the same target-level fallback rule as other combo
// strategies: non-ok target responses fall through to the next target.
// Classification stays here only to support cooldown/semaphore pacing,
// not to decide whether fallback is allowed.
const { cooldownMs } = checkFallbackError(
result.status,
errorText,
0,
null,
provider,
result.headers,
profile
);
const isAllAccountsRateLimited = isAllAccountsRateLimitedResponse(
result.status,
result.headers?.get("content-type") ?? null,
errorText
);
// Transient errors → mark in semaphore so round-robin stops stampeding this target.
if (TRANSIENT_FOR_SEMAPHORE.includes(result.status) && cooldownMs > 0) {
semaphore.markRateLimited(semaphoreKey, cooldownMs);
log.warn("COMBO-RR", `${modelStr} error ${result.status}, cooldown ${cooldownMs}ms`);
}
if (isAllAccountsRateLimited) {
log.info(
"COMBO-RR",
`All accounts rate-limited for ${modelStr}, falling back to next model`
);
}
// Transient error → retry same model
const isTransient =
!isStreamReadinessTimeout && [408, 429, 500, 502, 503, 504].includes(result.status);
if (retry < maxRetries && isTransient) {
continue;
}
// Done with this model
recordComboRequest(combo.name, modelStr, {
success: false,
latencyMs: Date.now() - startTime,
fallbackCount,
strategy: "round-robin",
target: toRecordedTarget(target),
});
recordedAttempts++;
lastError = errorText || String(result.status);
if (!lastStatus) lastStatus = result.status;
if (offset > 0) fallbackCount++;
log.warn("COMBO-RR", `${modelStr} failed, trying next model`, { status: result.status });
const fallbackWaitMs =
retryDelayMs > 0 && cooldownMs > 0 && cooldownMs <= MAX_FALLBACK_WAIT_MS
? Math.min(cooldownMs, retryDelayMs)
: 0;
if ([502, 503, 504].includes(result.status) && fallbackWaitMs > 0) {
log.info("COMBO-RR", `Waiting ${fallbackWaitMs}ms before fallback to next model`);
await new Promise((resolve) => {
const timer = setTimeout(resolve, fallbackWaitMs);
signal?.addEventListener(
"abort",
() => {
clearTimeout(timer);
resolve(undefined);
},
{ once: true }
);
});
if (signal?.aborted) {
log.info("COMBO-RR", `Client disconnected during fallback wait — aborting`);
return errorResponse(499, "Client disconnected");
}
}
break;
}
} finally {
// ALWAYS release semaphore slot
release();
}
}
// All models exhausted
const latencyMs = Date.now() - startTime;
if (recordedAttempts === 0) {
recordComboRequest(combo.name, null, {
success: false,
latencyMs,
fallbackCount,
strategy: "round-robin",
});
}
if (!lastStatus) {
return new Response(
JSON.stringify({
error: {
message: "Service temporarily unavailable: all upstream accounts are inactive",
type: "service_unavailable",
code: "ALL_ACCOUNTS_INACTIVE",
},
}),
{ status: 503, headers: { "Content-Type": "application/json" } }
);
}
const status = lastStatus;
const msg = lastError || "All round-robin combo models unavailable";
if (earliestRetryAfter) {
const retryHuman = formatRetryAfter(earliestRetryAfter);
log.warn("COMBO-RR", `All models failed | ${msg} (${retryHuman})`);
return unavailableResponse(status, msg, earliestRetryAfter, retryHuman);
}
log.warn("COMBO-RR", `All models failed | ${msg}`);
return new Response(JSON.stringify({ error: { message: msg } }), {
status,
headers: { "Content-Type": "application/json" },
});
}