diff --git a/docs/plugins.md b/docs/plugins.md
index 70fb617..52af73d 100644
--- a/docs/plugins.md
+++ b/docs/plugins.md
@@ -7,17 +7,11 @@ The path is relative to the bot's folder.
 Plugins are automatically loaded on bot startup.
 
 ## Creating a plugin
-Create a `.js` file that exports a function.
-This function will be called when the plugin is loaded, with 1 argument: an object that has the following properties:
-* `bot` - the [Eris Client object](https://abal.moe/Eris/docs/Client)
-* `knex` - the [Knex database object](https://knexjs.org/#Builder)
-* `config` - the loaded config
-* `commands` - an object with functions to add and manage commands
-* `attachments` - an object with functions to save attachments and manage attachment storage types
+Plugins are simply `.js` files that export a function that gets called when the plugin is loaded.
 
-See [src/plugins.js#L4](../src/plugins.js#L4) for more details
+For details about the function arguments, see [Plugin API](#plugin-api) below.
 
-### Example plugin file
+### Example plugin
 This example adds a command `!mycommand` that replies with `"Reply from my custom plugin!"` when the command is used inside a modmail inbox thread channel.
 ```js
 module.exports = function({ bot, knex, config, commands }) {
@@ -40,6 +34,36 @@ module.exports = function({ attachments }) {
 ```
 To use this custom attachment storage type, you would set the `attachmentStorage` config option to `"original"`.
 
+### Plugin API
+The first and only argument to the plugin function is an object with the following properties:
+
+| Property | Description |
+| -------- | ----------- |
+| `bot` | [Eris Client instance](https://abal.moe/Eris/docs/Client) |
+| `knex` | [Knex database object](https://knexjs.org/#Builder) |
+| `config` | The loaded config |
+| `commands` | An object with functions to add and manage commands |
+| `attachments` | An object with functions to save attachments and manage attachment storage types |
+| — `addStorageType(name, handler)` | Function to add a new attachment storage type |
+| — `downloadAttachment(attachment)` | Function to add a new attachment storage type |
+
+* `bot` - the [Eris Client object](https://abal.moe/Eris/docs/Client)
+* `knex` - the [Knex database object](https://knexjs.org/#Builder)
+* `config` - the loaded config
+* `commands` - an object with functions to add and manage commands
+* `attachments` - an object with functions to save attachments and manage attachment storage types
+    * `attachments.addStorageType(name, handler)`
+
+Create a `.js` file that exports a function.
+This function will be called when the plugin is loaded, with 1 argument: an object that has the following properties:
+* `bot` - the [Eris Client object](https://abal.moe/Eris/docs/Client)
+* `knex` - the [Knex database object](https://knexjs.org/#Builder)
+* `config` - the loaded config
+* `commands` - an object with functions to add and manage commands
+* `attachments` - an object with functions to save attachments and manage attachment storage types
+
+See [src/plugins.js#L4](../src/plugins.js#L4) for more details
+
 ## Work in progress
 The current plugin API is fairly rudimentary and will be expanded on in the future.
 The API can change in non-major releases during this early stage. Keep an eye on [CHANGELOG.md](../CHANGELOG.md) for any changes.
diff --git a/src/commands.js b/src/commands.js
index cdc95de..a0c34e2 100644
--- a/src/commands.js
+++ b/src/commands.js
@@ -5,6 +5,51 @@ const utils = require("./utils");
 const threads = require("./data/threads");
 const Thread = require("./data/Thread");
 
+/**
+ * @callback CommandFn
+ * @param {Eris.Message} msg
+ * @param {object} args
+ */
+
+/**
+ * @callback InboxThreadCommandHandler
+ * @param {Eris.Message} msg
+ * @param {object} args
+ * @param {Thread} thread
+ */
+
+/**
+ * @callback AddGlobalCommandFn
+ * @param {string} trigger
+ * @param {string} parameters
+ * @param {CommandFn} handler
+ * @param {ICommandConfig} commandConfig
+ */
+
+/**
+ * @callback AddInboxServerCommandFn
+ * @param {string} trigger
+ * @param {string} parameters
+ * @param {CommandFn} handler
+ * @param {ICommandConfig} commandConfig
+ */
+
+/**
+ * @callback AddInboxThreadCommandFn
+ * Add a command that can only be invoked in a thread on the inbox server
+ *
+ * @param {string} trigger
+ * @param {string} parameters
+ * @param {InboxThreadCommandHandler} handler
+ * @param {ICommandConfig} commandConfig
+ */
+
+/**
+ * @callback AddAliasFn
+ * @param {string} originalCmd
+ * @param {string} alias
+ */
+
 module.exports = {
   createCommandManager(bot) {
     const manager = new CommandManager({
@@ -52,6 +97,7 @@ module.exports = {
 
     /**
      * Add a command that can be invoked anywhere
+     * @type {AddGlobalCommandFn}
      */
     const addGlobalCommand = (trigger, parameters, handler, commandConfig = {}) => {
       let aliases = aliasMap.has(trigger) ? [...aliasMap.get(trigger)] : [];
@@ -63,6 +109,7 @@ module.exports = {
 
     /**
      * Add a command that can only be invoked on the inbox server
+     * @type {AddInboxServerCommandFn}
      */
     const addInboxServerCommand = (trigger, parameters, handler, commandConfig = {}) => {
       const aliases = aliasMap.has(trigger) ? [...aliasMap.get(trigger)] : [];
@@ -86,19 +133,9 @@ module.exports = {
       };
     };
 
-    /**
-     * @callback InboxThreadCommandHandler
-     * @param {Eris.Message} msg
-     * @param {object} args
-     * @param {Thread} thread
-     */
-
     /**
      * Add a command that can only be invoked in a thread on the inbox server
-     * @param {string|RegExp} trigger
-     * @param {string|IParameter[]} parameters
-     * @param {InboxThreadCommandHandler} handler
-     * @param {ICommandConfig} commandConfig
+     * @type {AddInboxThreadCommandFn}
      */
     const addInboxThreadCommand = (trigger, parameters, handler, commandConfig = {}) => {
       const aliases = aliasMap.has(trigger) ? [...aliasMap.get(trigger)] : [];
@@ -124,6 +161,9 @@ module.exports = {
       };
     };
 
+    /**
+     * @type {AddAliasFn}
+     */
     const addAlias = (originalCmd, alias) => {
       if (! aliasMap.has(originalCmd)) {
         aliasMap.set(originalCmd, new Set());
diff --git a/src/data/attachments.js b/src/data/attachments.js
index c26d056..a5392c0 100644
--- a/src/data/attachments.js
+++ b/src/data/attachments.js
@@ -26,21 +26,54 @@ function getErrorResult(msg = null) {
 }
 
 /**
- * An attachment storage option that simply forwards the original attachment URL
- * @param {Eris.Attachment} attachment
- * @returns {{url: string}}
+ * @callback AddAttachmentStorageTypeFn
+ * @param {string} name
+ * @param {AttachmentStorageTypeHandler} handler
  */
-function passthroughOriginalAttachment(attachment) {
+
+/**
+ * @callback AttachmentStorageTypeHandler
+ * @param {Eris.Attachment} attachment
+ * @return {AttachmentStorageTypeResult|Promise<AttachmentStorageTypeResult>}
+ */
+
+/**
+ * @typedef {object} AttachmentStorageTypeResult
+ * @property {string} url
+ */
+
+/**
+ * @callback DownloadAttachmentFn
+ * @param {Eris.Attachment} attachment
+ * @param {number?} tries Used internally, don't pass
+ * @return {Promise<DownloadAttachmentResult>}
+  */
+
+/**
+ * @typedef {object} DownloadAttachmentResult
+ * @property {string} path
+ * @property {DownloadAttachmentCleanupFn} cleanup
+ */
+
+/**
+ * @callback DownloadAttachmentCleanupFn
+ * @return {void}
+ */
+
+/**
+ * @type {AttachmentStorageTypeHandler}
+ */
+let passthroughOriginalAttachment; // Workaround to inconsistent IDE bug with @type and anonymous functions
+passthroughOriginalAttachment = (attachment) => {
   return { url: attachment.url };
-}
+};
 
 /**
  * An attachment storage option that downloads each attachment and serves them from a local web server
- * @param {Eris.Attachment} attachment
- * @param {Number=0} tries
- * @returns {Promise<{ url: string }>}
+ * @type {AttachmentStorageTypeHandler}
  */
-async function saveLocalAttachment(attachment) {
+let saveLocalAttachment; // Workaround to inconsistent IDE bug with @type and anonymous functions
+saveLocalAttachment = async (attachment) => {
   const targetPath = getLocalAttachmentPath(attachment.id);
 
   try {
@@ -60,14 +93,12 @@ async function saveLocalAttachment(attachment) {
   const url = await getLocalAttachmentUrl(attachment.id, attachment.filename);
 
   return { url };
-}
+};
 
 /**
- * @param {Eris.Attachment} attachment
- * @param {Number} tries
- * @returns {Promise<{ path: string, cleanup: function }>}
+ * @type {DownloadAttachmentFn}
  */
-function downloadAttachment(attachment, tries = 0) {
+const downloadAttachment = (attachment, tries = 0) => {
   return new Promise((resolve, reject) => {
     if (tries > 3) {
       console.error("Attachment download failed after 3 tries:", attachment);
@@ -94,7 +125,7 @@ function downloadAttachment(attachment, tries = 0) {
       });
     });
   });
-}
+};
 
 /**
  * Returns the filesystem path for the given attachment id
@@ -119,10 +150,10 @@ function getLocalAttachmentUrl(attachmentId, desiredName = null) {
 /**
  * An attachment storage option that downloads each attachment and re-posts them to a specified Discord channel.
  * The re-posted attachment is then linked in the actual thread.
- * @param {Eris.Attachment} attachment
- * @returns {Promise<{ url: string }>}
+ * @type {AttachmentStorageTypeHandler}
  */
-async function saveDiscordAttachment(attachment) {
+let saveDiscordAttachment; // Workaround to inconsistent IDE bug with @type and anonymous functions
+saveDiscordAttachment = async (attachment) => {
   if (attachment.size > 1024 * 1024 * 8) {
     return getErrorResult("attachment too large (max 8MB)");
   }
@@ -144,7 +175,7 @@ async function saveDiscordAttachment(attachment) {
   if (! savedAttachment) return getErrorResult();
 
   return { url: savedAttachment.url };
-}
+};
 
 async function createDiscordAttachmentMessage(channel, file, tries = 0) {
   tries++;
@@ -197,9 +228,12 @@ function saveAttachment(attachment) {
   return attachmentSavePromises[attachment.id];
 }
 
-function addStorageType(name, handler) {
+/**
+ * @type AddAttachmentStorageTypeFn
+ */
+const addStorageType = (name, handler) => {
   attachmentStorageTypes[name] = handler;
-}
+};
 
 addStorageType("original", passthroughOriginalAttachment);
 addStorageType("local", saveLocalAttachment);
diff --git a/src/formatters.js b/src/formatters.js
index e329685..6693276 100644
--- a/src/formatters.js
+++ b/src/formatters.js
@@ -212,6 +212,20 @@ const defaultFormatters = {
  */
 const formatters = { ...defaultFormatters };
 
+/**
+ * @typedef {object} FormattersExport
+ * @property {MessageFormatters} formatters Read only
+ * @property {function(FormatStaffReplyDM): void} setStaffReplyDMFormatter
+ * @property {function(FormatStaffReplyThreadMessage): void} setStaffReplyThreadMessageFormatter
+ * @property {function(FormatUserReplyThreadMessage): void} setUserReplyThreadMessageFormatter
+ * @property {function(FormatStaffReplyEditNotificationThreadMessage): void} setStaffReplyEditNotificationThreadMessageFormatter
+ * @property {function(FormatStaffReplyDeletionNotificationThreadMessage): void} setStaffReplyDeletionNotificationThreadMessageFormatter
+ * @property {function(FormatLog): void} setLogFormatter
+ */
+
+/**
+ * @type {FormattersExport}
+ */
 module.exports = {
   formatters: new Proxy(formatters, {
     set() {
@@ -219,50 +233,26 @@ module.exports = {
     },
   }),
 
-  /**
-   * @param {FormatStaffReplyDM} fn
-   * @return {void}
-   */
   setStaffReplyDMFormatter(fn) {
     formatters.formatStaffReplyDM = fn;
   },
 
-  /**
-   * @param {FormatStaffReplyThreadMessage} fn
-   * @return {void}
-   */
   setStaffReplyThreadMessageFormatter(fn) {
     formatters.formatStaffReplyThreadMessage = fn;
   },
 
-  /**
-   * @param {FormatUserReplyThreadMessage} fn
-   * @return {void}
-   */
   setUserReplyThreadMessageFormatter(fn) {
     formatters.formatUserReplyThreadMessage = fn;
   },
 
-  /**
-   * @param {FormatStaffReplyEditNotificationThreadMessage} fn
-   * @return {void}
-   */
   setStaffReplyEditNotificationThreadMessageFormatter(fn) {
     formatters.formatStaffReplyEditNotificationThreadMessage = fn;
   },
 
-  /**
-   * @param {FormatStaffReplyDeletionNotificationThreadMessage} fn
-   * @return {void}
-   */
   setStaffReplyDeletionNotificationThreadMessageFormatter(fn) {
     formatters.formatStaffReplyDeletionNotificationThreadMessage = fn;
   },
 
-  /**
-   * @param {FormatLog} fn
-   * @return {void}
-   */
   setLogFormatter(fn) {
     formatters.formatLog = fn;
   },
diff --git a/src/hooks/beforeNewThread.js b/src/hooks/beforeNewThread.js
index 9805843..e0173aa 100644
--- a/src/hooks/beforeNewThread.js
+++ b/src/hooks/beforeNewThread.js
@@ -26,17 +26,24 @@ const Eris = require("eris");
  * @return {void|Promise<void>}
  */
 
+/**
+ * @callback AddBeforeNewThreadHookFn
+ * @param {BeforeNewThreadHookData} fn
+ * @return {void}
+ */
+
 /**
  * @type BeforeNewThreadHookData[]
  */
 const beforeNewThreadHooks = [];
 
 /**
- * @param {BeforeNewThreadHookData} fn
+ * @type {AddBeforeNewThreadHookFn}
  */
-function beforeNewThread(fn) {
+let beforeNewThread; // Workaround to inconsistent IDE bug with @type and anonymous functions
+beforeNewThread = (fn) => {
   beforeNewThreadHooks.push(fn);
-}
+};
 
 /**
  * @param {{
diff --git a/src/pluginApi.js b/src/pluginApi.js
new file mode 100644
index 0000000..65d8227
--- /dev/null
+++ b/src/pluginApi.js
@@ -0,0 +1,34 @@
+const { CommandManager } = require("knub-command-manager");
+const { Client } = require("eris");
+const Knex = require("knex");
+
+/**
+ * @typedef {object} PluginAPI
+ * @property {Client} bot
+ * @property {Knex} knex
+ * @property {ModmailConfig} config
+ * @property {PluginCommandsAPI} commands
+ * @property {PluginAttachmentsAPI} attachments
+ * @property {PluginHooksAPI} hooks
+ * @property {FormattersExport} formats
+ */
+
+/**
+ * @typedef {object} PluginCommandsAPI
+ * @property {CommandManager} manager
+ * @property {AddGlobalCommandFn} addGlobalCommand
+ * @property {AddInboxServerCommandFn} addInboxServerCommand
+ * @property {AddInboxThreadCommandFn} addInboxThreadCommand
+ * @property {AddAliasFn} addAlias
+ */
+
+/**
+ * @typedef {object} PluginAttachmentsAPI
+ * @property {AddAttachmentStorageTypeFn} addStorageType
+ * @property {DownloadAttachmentFn} downloadAttachment
+ */
+
+/**
+ * @typedef {object} PluginHooksAPI
+ * @property {AddBeforeNewThreadHookFn} beforeNewThread
+ */
diff --git a/src/plugins.js b/src/plugins.js
index d03c2ae..f27cf50 100644
--- a/src/plugins.js
+++ b/src/plugins.js
@@ -3,6 +3,13 @@ const { beforeNewThread } = require("./hooks/beforeNewThread");
 const formats = require("./formatters");
 
 module.exports = {
+  /**
+   * @param bot
+   * @param knex
+   * @param config
+   * @param commands
+   * @returns {PluginAPI}
+   */
   getPluginAPI({ bot, knex, config, commands }) {
     return {
       bot,