📊 feat: Real-Time Context Window & Token Usage Tracking

api/server/controllers/TokenConfigController.js

@@ -0,0 +1,50 @@
+const { logger } = require('@librechat/data-schemas');
+const { EModelEndpoint } = require('librechat-data-provider');
+const { buildTokenConfigMap, getTokenConfigKey, tokenConfigCache } = require('@librechat/api');
+const { getModelsConfig } = require('~/server/controllers/ModelController');
+const { getValueKey, getMultiplier, getCacheMultiplier } = require('~/models');
+
+/**
+ * Returns server-resolved context windows (and pricing when
+ * `interface.contextCost` is enabled) for every configured model.
+ * @param {ServerRequest} req
+ * @param {ServerResponse} res
+ */
+async function tokenConfigController(req, res) {
+  try {
+    const appConfig = req.config;
+    const includePricing = appConfig?.interfaceConfig?.contextCost === true;
+    const modelsConfig = await getModelsConfig(req);
+
+    /** @type {Record<string, import('@librechat/api').EndpointTokenConfig | undefined>} */
+    const endpointTokenConfigs = {};
+    const customEndpoints = appConfig?.endpoints?.[EModelEndpoint.custom] ?? [];
+    const cache = tokenConfigCache();
+    for (const endpointConfig of customEndpoints) {
+      const name = endpointConfig?.name;
+      if (!name) {
+        continue;
+      }
+      if (endpointConfig.tokenConfig != null) {
+        endpointTokenConfigs[name] = endpointConfig.tokenConfig;
+        continue;
+      }
+      const tokenKey = getTokenConfigKey(endpointConfig, name, req.user.id);
+      const cached = await cache.get(tokenKey);
+      if (cached) {
+        endpointTokenConfigs[name] = cached;
+      }
+    }
+
+    const tokenConfigMap = buildTokenConfigMap(
+      { modelsConfig, endpointTokenConfigs, includePricing },
+      { getValueKey, getMultiplier, getCacheMultiplier },
+    );
+    res.json(tokenConfigMap);
+  } catch (error) {
+    logger.error('[tokenConfigController]', error);
+    res.status(500).json({ error: 'Failed to resolve token config' });
+  }
+}
+
+module.exports = tokenConfigController;