diff --git a/eslint.config.js b/eslint.config.js
new file mode 100644
index 0000000..c911968
--- /dev/null
+++ b/eslint.config.js
@@ -0,0 +1,57 @@
+import jsdoc from "eslint-plugin-jsdoc";
+
+// Cloudflare Workers globals + custom codebase types that no-undefined-types
+// must treat as defined (no tsc/jsconfig — plain ESM JS).
+const DEFINED_TYPES = [
+  // Cloudflare Workers runtime globals
+  "KVNamespace",
+  "D1Database",
+  "D1PreparedStatement",
+  // Web globals not always in eslint's scope
+  "Request",
+  "Response",
+  "URL",
+  // KV interface types (src/db/kv-store-interface.js)
+  "KVStore",
+  "KVStorePutOptions",
+  "KVStoreListOptions",
+  "KVStoreListResult",
+  // SQL interface types (src/db/sql-store-interface.js)
+  "SqlStore",
+  "SqlRunResult",
+  // Central typedefs (src/types.js)
+  "Env",
+  "Module",
+  "Command",
+  "Cron",
+  "ModuleContext",
+  "Trade",
+  "Portfolio",
+  "PortfolioMeta",
+  // Module sub-types (registry, validate-*)
+  "BotModule",
+  "RegistryEntry",
+  "Registry",
+  "ModuleCommand",
+  "ModuleCron",
+  "CronEntry",
+  // Trading sub-types
+  "ResolvedSymbol",
+];
+
+export default [
+  {
+    files: ["src/**/*.js"],
+    plugins: { jsdoc },
+    rules: {
+      "jsdoc/check-alignment": "warn",
+      "jsdoc/check-param-names": "error",
+      "jsdoc/check-tag-names": "error",
+      "jsdoc/check-types": "error",
+      "jsdoc/no-undefined-types": ["error", { definedTypes: DEFINED_TYPES }],
+      "jsdoc/require-param-type": "error",
+      "jsdoc/require-returns-type": "error",
+      "jsdoc/valid-types": "error",
+    },
+  },
+];
diff --git a/src/types.js b/src/types.js
new file mode 100644
index 0000000..34c85f6
--- /dev/null
+++ b/src/types.js
@@ -0,0 +1,95 @@
+/**
+ * @file Central JSDoc typedefs for the miti99bot codebase.
+ *
+ * No runtime exports — this file exists solely to provide type definitions
+ * that are visible to editor tooling and validated by eslint-plugin-jsdoc.
+ *
+ * Import-reexport typedefs from sub-modules live here so that consumers
+ * can `@typedef {import("../types.js").Env} Env` without chasing paths.
+ */
+
+/**
+ * Cloudflare Worker bindings + environment variables.
+ *
+ * @typedef {object} Env
+ * @property {string} TELEGRAM_BOT_TOKEN — bot token from BotFather.
+ * @property {string} TELEGRAM_WEBHOOK_SECRET — secret for X-Telegram-Bot-Api-Secret-Token header.
+ * @property {string} MODULES — comma-separated list of module names to load (e.g. "trading,wordle").
+ * @property {KVNamespace} KV — Cloudflare KV namespace binding.
+ * @property {D1Database|undefined} DB — Cloudflare D1 database binding; absent when not configured.
+ */
+
+/**
+ * A single slash-command registered by a module.
+ *
+ * @typedef {object} Command
+ * @property {string} name — without leading slash; must match /^[a-z0-9_]{1,32}$/.
+ * @property {"public"|"protected"|"private"} visibility
+ *   public: shown in Telegram /menu + /help.
+ *   protected: shown in /help only.
+ *   private: hidden easter egg — functional but undiscoverable.
+ * @property {string} description — ≤256 chars; required for all visibilities.
+ * @property {(ctx: any) => Promise<void>} handler — grammY context handler.
+ */
+
+/**
+ * A scheduled cron job registered by a module.
+ *
+ * @typedef {object} Cron
+ * @property {string} schedule — cron expression (e.g. "0 0 * * *").
+ * @property {string} name — human-readable identifier for logging.
+ * @property {(event: any, ctx: ModuleContext) => Promise<void>} handler — receives the scheduled event and module context.
+ */
+
+/**
+ * Context object passed to module init() and cron handlers.
+ *
+ * @typedef {object} ModuleContext
+ * @property {KVStore} db — namespaced KV store for this module.
+ * @property {SqlStore|null} sql — namespaced D1 store; null when env.DB is not bound.
+ * @property {Env} env — raw worker environment bindings.
+ */
+
+/**
+ * A plug-n-play module definition.
+ *
+ * @typedef {object} Module
+ * @property {string} name — unique module identifier; must match folder name and import-map key.
+ * @property {(ctx: ModuleContext) => Promise<void>} [init] — optional async setup called once at startup.
+ * @property {Command[]} commands — slash-commands provided by this module.
+ * @property {Cron[]} [crons] — optional scheduled jobs provided by this module.
+ */
+
+/**
+ * A single trade record stored in D1.
+ *
+ * @typedef {object} Trade
+ * @property {number} id — auto-increment primary key.
+ * @property {number} userId — Telegram user ID.
+ * @property {string} symbol — asset ticker (e.g. "TCB", "BTC").
+ * @property {"buy"|"sell"} side — direction of the trade.
+ * @property {number} qty — quantity traded (integer for stocks).
+ * @property {number} priceVnd — execution price in VND.
+ * @property {number} ts — Unix timestamp (ms) of the trade.
+ */
+
+// Re-export typedefs from sub-modules so consumers have a single import path.
+/**
+ * @typedef {import("./db/kv-store-interface.js").KVStore} KVStore
+ * @typedef {import("./db/kv-store-interface.js").KVStorePutOptions} KVStorePutOptions
+ * @typedef {import("./db/kv-store-interface.js").KVStoreListOptions} KVStoreListOptions
+ * @typedef {import("./db/kv-store-interface.js").KVStoreListResult} KVStoreListResult
+ */
+
+/**
+ * @typedef {import("./db/sql-store-interface.js").SqlStore} SqlStore
+ * @typedef {import("./db/sql-store-interface.js").SqlRunResult} SqlRunResult
+ */
+
+/**
+ * @typedef {import("./modules/trading/portfolio.js").Portfolio} Portfolio
+ * @typedef {import("./modules/trading/portfolio.js").PortfolioMeta} PortfolioMeta
+ */
+
+// JSDoc-only module. No runtime exports.
+export {};