One of the most critical aspects of interactive Discord commands is identifying who the command should target. When a user runs !avatar @username, !avatar 123456789012345678, or simply !avatar, your bot should process each of these inputs gracefully.

In this guide, we will explore advanced user targeting techniques in Bot Designer for Discord (BDFD) / Bot Creator using $mentioned, $findUser, and $authorID.

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🔍 Targeting Functions Overview

BDFD offers several distinct functions to retrieve user IDs from command arguments. Choosing the correct function will dictate how flexible your command is:

Function	What it does	Best Used For
$authorID	Instantly retrieves the ID of the command initiator.	Command context fallbacks, setting defaults.
$mentioned[index;(returnAuthorIfEmpty)]	Retrieves the ID of the user directly pinged in the command.	Strict, mention-only commands.
$findUser[query;(fallback)]	Resolves raw text (a ping, a user ID, or an exact username) to the ID of a member of the current server.	Flexible commands and moderation tools (!warn, !ban, !kick).

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1. Strict Mention Checking ($mentioned)

If you want a command that only triggers when a user is explicitly highlighted using Discord pings, use $mentioned:

$mentioned[index;(returnAuthorIfEmpty)]

• index: The order of the mention (e.g., 1 for the first ping, 2 for the second). < means the first ping and > the last one. Anything else (like 0) is an error. It only works for message commands, not slash commands.
• returnAuthorIfEmpty: (Optional, yes or no, also true/false). When omitted it behaves like yes: if there is no ping at that index, the initiator’s ID is returned. Write no to get an empty text instead.

Code Example: Strict Mentions

$nomention
$if[$mentioned[1;no]==]
  ❌ You must ping a user to execute this action! Example: `!slap @user`
$else
  💥 $username slapped $username[$mentioned[1]]! That's gotta hurt!
$endif

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2. Advanced Global User Lookup ($findUser)

The $findUser function is the gold standard for commands requiring extreme user flexibility. It parses a string argument and tries to find a matching member of the current server:

$findUser[query;(fallbackToAuthor)]

• query: The string input to search. Usually the first word typed after the command, $message[1]. The whole $message only works when the message contains nothing but the ping, ID or username (extra words make the lookup fail). It is matched, in this order, as a ping (<@123...> or <@!123...>), as a user ID, and as an exact username (case-sensitive, no partial match). A ping or ID only matches if that user is a member of the server; ping lookups never fall back to a username search.
• fallbackToAuthor: (Optional, yes/no; also accepts true/false, on/off, enable/disable). When omitted it behaves like yes: the function returns the initiator’s ID when the query matches nothing or is blank. With no it returns an empty text instead.

Code Example: Avatar Command

Let’s build a beautiful avatar viewer command that handles mentions, raw Snowflake IDs, usernames, or defaults to the caller:

$nomention
$var[targetID;$findUser[$message[1];yes]]

$title[🖼️ Avatar of $username[$var[targetID]]]
$color[#3b82f6]
$image[$userAvatar[$var[targetID]]]
$footer[Requested by $username]
$footerIcon[$authorAvatar]
$addTimestamp

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3. Robust Lookup for Moderation ($findUser)

For moderation commands, $findUser is essential to target a member securely and flexibly:

Code Example: Kick Command

$nomention
$onlyPerms[kickmembers;❌ You need the `Kick Members` permission to run this!]

$var[targetID;$findUser[$message[1];no]]

$if[$var[targetID]==]
  ❌ Member not found! Please provide a valid username, mention, or ID.
$else
    $if[$var[targetID]==$authorID]
      ❌ You cannot kick yourself!
    $else
      $kick[$var[targetID]]
      ✅ **$username[$var[targetID]]** has been kicked.
    $endif
$endif

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🛠️ Design Best Practices

A. Always Filter Mentions Out of Messages

$noMentionMessage returns the message text with user, role and channel pings (<@id>, <@!id>, <@&id>, <#id>) removed. Use it when you want to search by the remaining text only.

B. Clean Username Fallbacks

When printing usernames of resolved targets, always use $username[userID] or $displayName[userID] to ensure your output looks clean and professional, rather than showing raw Snowflake numbers.