feat(kimchi): add Kimchi OAuth provider support

Add Kimchi as a browser-token OAuth provider routed through its
OpenAI-compatible gateway. Discover live models for /v1/models and
provider models, normalize Claude-compatible requests, and wire up
provider connection tests.

Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/services/kimchiModels.js

@@ -0,0 +1,176 @@
+import { createHash } from "crypto";
+
+import { proxyAwareFetch } from "../utils/proxyFetch.js";
+
+export const KIMCHI_API = "https://llm.kimchi.dev";
+export const KIMCHI_USER_AGENT = "kimchi/0.0.0";
+
+const FETCH_TIMEOUT_MS = 20_000;
+const CACHE_TTL_MS = 5 * 60 * 1000;
+const RETRYABLE_STATUSES = new Set([429, 500, 502, 503, 504]);
+
+/** @type {Map<string, { expiresAt: number, models: object[], rawModels: object[] }>} */
+const catalogCache = new Map();
+/** @type {Map<string, object>} */
+const metadataByModelId = new Map();
+
+function normalizeKimchiEndpoint(endpoint) {
+  const raw = typeof endpoint === "string" ? endpoint.trim() : "";
+  return (raw || KIMCHI_API).replace(/\/+$/, "");
+}
+
+export function buildKimchiModelsUrl(endpoint) {
+  return `${normalizeKimchiEndpoint(endpoint)}/v1/models/metadata?include_in_cli=true`;
+}
+
+function readToken(credentials) {
+  return (
+    credentials?.accessToken
+    || credentials?.apiKey
+    || credentials?.providerSpecificData?.apiKey
+    || null
+  );
+}
+
+function cacheKey(credentials, endpoint) {
+  const psd = credentials?.providerSpecificData || {};
+  const seed = psd.userId || psd.username || credentials?.refreshToken || readToken(credentials) || "anonymous";
+  return createHash("sha256")
+    .update(`kimchi:${normalizeKimchiEndpoint(endpoint)}:${seed}`)
+    .digest("hex");
+}
+
+function toModelKind(inputModalities) {
+  return Array.isArray(inputModalities) && inputModalities.includes("image")
+    ? "imageToText"
+    : "llm";
+}
+
+export function normalizeKimchiModel(item) {
+  if (!item || typeof item !== "object") return null;
+  const id = item.slug || item.id || item.model || item.name;
+  if (typeof id !== "string" || id.trim() === "") return null;
+
+  const inputModalities = Array.isArray(item.input_modalities)
+    ? item.input_modalities.filter((value) => value === "text" || value === "image")
+    : [];
+  const limits = item.limits && typeof item.limits === "object" ? item.limits : {};
+  const contextLength = Number(limits.context_window || item.contextLength || item.context_length) || undefined;
+  const maxOutputTokens = Number(limits.max_output_tokens || item.maxOutputTokens || item.max_output_tokens) || undefined;
+  const upstreamProvider = typeof item.provider === "string" ? item.provider : "";
+  const reasoning = item.reasoning === true;
+  const kind = toModelKind(inputModalities);
+
+  const model = {
+    ...item,
+    id: id.trim(),
+    name: String(item.display_name || item.displayName || item.name || id).trim(),
+    provider: upstreamProvider,
+    upstreamProvider,
+    reasoning,
+    inputModalities,
+    kind,
+    type: kind,
+    capabilities: {
+      vision: inputModalities.includes("image"),
+      reasoning,
+      ...(contextLength ? { contextWindow: contextLength } : {}),
+      ...(maxOutputTokens ? { maxOutput: maxOutputTokens } : {}),
+      ...(upstreamProvider ? { upstreamProvider } : {}),
+    },
+    ...(contextLength ? { contextLength } : {}),
+    ...(maxOutputTokens ? { maxOutputTokens } : {}),
+  };
+
+  if (upstreamProvider === "anthropic") {
+    model.compat = { supportsReasoningEffort: false, cacheControlFormat: "anthropic" };
+  }
+
+  return model;
+}
+
+function rememberModels(models) {
+  for (const model of models || []) {
+    if (!model?.id) continue;
+    metadataByModelId.set(model.id, model);
+    metadataByModelId.set(model.id.toLowerCase(), model);
+  }
+}
+
+export function getCachedKimchiModelMetadata(modelId) {
+  if (typeof modelId !== "string" || modelId.trim() === "") return null;
+  const raw = modelId.includes("/") ? modelId.split("/").pop() : modelId;
+  return metadataByModelId.get(raw) || metadataByModelId.get(raw.toLowerCase()) || null;
+}
+
+async function fetchKimchiCatalogRaw(token, endpoint, options = {}) {
+  const url = buildKimchiModelsUrl(endpoint);
+  const controller = new AbortController();
+  const timeout = setTimeout(() => controller.abort(new Error("Kimchi models fetch timeout")), FETCH_TIMEOUT_MS);
+  const signal = options.signal
+    ? AbortSignal.any([options.signal, controller.signal])
+    : controller.signal;
+
+  try {
+    const response = await proxyAwareFetch(url, {
+      method: "GET",
+      headers: {
+        "Accept": "application/json",
+        "Authorization": `Bearer ${token}`,
+        "User-Agent": KIMCHI_USER_AGENT,
+      },
+      cache: "no-store",
+      signal,
+    }, options.proxyOptions || null);
+
+    if (!response.ok) {
+      const error = new Error(`Kimchi models ${response.status}: ${response.statusText}`);
+      error.status = response.status;
+      error.retryable = RETRYABLE_STATUSES.has(response.status);
+      throw error;
+    }
+
+    const data = await response.json();
+    return Array.isArray(data?.models) ? data.models : [];
+  } finally {
+    clearTimeout(timeout);
+  }
+}
+
+export async function resolveKimchiModels(credentials, options = {}) {
+  const token = readToken(credentials);
+  if (!token) return null;
+
+  const endpoint = credentials?.providerSpecificData?.kimchiEndpoint || options.endpoint || KIMCHI_API;
+  const key = cacheKey(credentials, endpoint);
+  const now = Date.now();
+  if (!options.forceRefresh) {
+    const cached = catalogCache.get(key);
+    if (cached && cached.expiresAt > now) return cached;
+  }
+
+  let rawModels;
+  try {
+    rawModels = await fetchKimchiCatalogRaw(token, endpoint, options);
+  } catch (error) {
+    options.log?.warn?.("KIMCHI_MODELS", error.message);
+    return null;
+  }
+
+  const models = rawModels.map(normalizeKimchiModel).filter(Boolean);
+  if (models.length === 0) return null;
+
+  rememberModels(models);
+  const entry = {
+    expiresAt: Date.now() + CACHE_TTL_MS,
+    models,
+    rawModels,
+  };
+  catalogCache.set(key, entry);
+  return entry;
+}
+
+export function clearKimchiCatalog() {
+  catalogCache.clear();
+  metadataByModelId.clear();
+}