diff --git a/src/benchmark.cr b/src/benchmark.cr
index 59cad44ba13e..a581af2ad23b 100644
--- a/src/benchmark.cr
+++ b/src/benchmark.cr
@@ -3,6 +3,8 @@ require "./benchmark/**"
 # The Benchmark module provides methods for benchmarking Crystal code, giving
 # detailed reports on the time and memory taken for each task.
 #
+# NOTE: To use `Benchmark`, you must explicitly import it with `require "benchmark"` 
+#
 # ### Measure the number of iterations per second of each task
 #
 # ```
diff --git a/src/big/big_decimal.cr b/src/big/big_decimal.cr
index b5d9e93f2d29..470c61e3e85f 100644
--- a/src/big/big_decimal.cr
+++ b/src/big/big_decimal.cr
@@ -12,6 +12,8 @@ end
 # Value contains the actual value, and scale tells the decimal point place.
 # E.g. when value is `1234` and scale `2`, the result is `12.34`.
 #
+# NOTE: To use `BigDecimal`, you must explicitly import it with `require "big"`
+#
 # The general idea and some of the arithmetic algorithms were adapted from
 # the MIT/APACHE-licensed [bigdecimal-rs](https://github.com/akubera/bigdecimal-rs).
 struct BigDecimal < Number
diff --git a/src/big/big_float.cr b/src/big/big_float.cr
index 7c90a6985207..cc455c7c56cd 100644
--- a/src/big/big_float.cr
+++ b/src/big/big_float.cr
@@ -4,6 +4,8 @@ require "big"
 # A `BigFloat` can represent arbitrarily large floats.
 #
 # It is implemented under the hood with [GMP](https://gmplib.org/).
+#
+# NOTE: To use `BigFloat`, you must explicitly import it with `require "big"`
 struct BigFloat < Float
   include Comparable(Int)
   include Comparable(BigFloat)
diff --git a/src/big/big_int.cr b/src/big/big_int.cr
index aaae48999938..e1ca94dbd10b 100644
--- a/src/big/big_int.cr
+++ b/src/big/big_int.cr
@@ -5,6 +5,8 @@ require "random"
 # A `BigInt` can represent arbitrarily large integers.
 #
 # It is implemented under the hood with [GMP](https://gmplib.org/).
+#
+# NOTE: To use `BigInt`, you must explicitly import it with `require "big"`
 struct BigInt < Int
   include Comparable(Int::Signed)
   include Comparable(Int::Unsigned)
diff --git a/src/big/big_rational.cr b/src/big/big_rational.cr
index c87273788fef..acb34838ca3f 100644
--- a/src/big/big_rational.cr
+++ b/src/big/big_rational.cr
@@ -5,6 +5,8 @@ require "big"
 # denominator and the numerator have no common factors, and that the
 # denominator is positive. Zero has the unique representation 0/1.
 #
+# NOTE: To use `BigRational`, you must explicitly import it with `require "big"`
+#
 # ```
 # require "big"
 #
diff --git a/src/bit_array.cr b/src/bit_array.cr
index 080c8475765b..4f4eb5726055 100644
--- a/src/bit_array.cr
+++ b/src/bit_array.cr
@@ -4,6 +4,8 @@
 # `UInt32`s. The total number of bits stored is set at creation and is
 # immutable.
 #
+# NOTE: To use `BitArray`, you must explicitly import it with `require "bit_array"`
+#
 # ### Example
 #
 # ```
diff --git a/src/colorize.cr b/src/colorize.cr
index 8cdd6648e8ff..4fee40faf616 100644
--- a/src/colorize.cr
+++ b/src/colorize.cr
@@ -3,6 +3,8 @@
 # as its main interface, which calls `to_s` and surrounds it with the necessary escape codes
 # when it comes to obtaining a string representation of the object.
 #
+# NOTE: To use `Colorize`, you must explicitly import it with `require "colorize"`
+#
 # Its first argument changes the foreground color:
 #
 # ```
diff --git a/src/complex.cr b/src/complex.cr
index 6fd1d2a2faf2..d4e648e9c8fe 100644
--- a/src/complex.cr
+++ b/src/complex.cr
@@ -3,6 +3,8 @@
 # The a is the real part of the number, and the b is the imaginary part of
 # the number.
 #
+# NOTE: To use `Complex`, you must explicitly import it with `require "complex"`
+#
 # ```
 # require "complex"
 #
diff --git a/src/compress/deflate/deflate.cr b/src/compress/deflate/deflate.cr
index 4c6ee0cdc145..58479f503fbf 100644
--- a/src/compress/deflate/deflate.cr
+++ b/src/compress/deflate/deflate.cr
@@ -6,6 +6,8 @@ require "./*"
 #
 # See `Gzip`, `Zip` and `Zlib` for modules that provide access
 # to DEFLATE-based file formats.
+#
+# NOTE: To use `Deflate` or its children, you must explicitly import it with `require "compress/deflate"`
 module Compress::Deflate
   NO_COMPRESSION      =  0
   BEST_SPEED          =  1
diff --git a/src/compress/gzip/gzip.cr b/src/compress/gzip/gzip.cr
index 616c25422a05..2d8ffcd81338 100644
--- a/src/compress/gzip/gzip.cr
+++ b/src/compress/gzip/gzip.cr
@@ -3,6 +3,8 @@ require "digest/crc32"
 
 # The Gzip module contains readers and writers of gzip format compressed
 # data, as specified in [RFC 1952](https://www.ietf.org/rfc/rfc1952.txt).
+#
+# NOTE: To use `Gzip` or its children, you must explicitly import it with `require "compress/gzip"`
 module Compress::Gzip
   NO_COMPRESSION      = Compress::Deflate::NO_COMPRESSION
   BEST_SPEED          = Compress::Deflate::BEST_SPEED
diff --git a/src/compress/zip/zip.cr b/src/compress/zip/zip.cr
index 61da653dabec..ec03826fcba8 100644
--- a/src/compress/zip/zip.cr
+++ b/src/compress/zip/zip.cr
@@ -4,6 +4,8 @@ require "digest/crc32"
 # The Compress::Zip module contains readers and writers of the zip
 # file format, described at [PKWARE's site](https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.3.TXT).
 #
+# NOTE: To use `Zip` or its children, you must explicitly import it with `require "compress/zip"`
+#
 # ### Reading zip files
 #
 # Two types are provided to read from zip files:
diff --git a/src/compress/zlib/zlib.cr b/src/compress/zlib/zlib.cr
index b996c825e742..0326f24bf815 100644
--- a/src/compress/zlib/zlib.cr
+++ b/src/compress/zlib/zlib.cr
@@ -3,6 +3,8 @@ require "digest/adler32"
 
 # The Compress::Zlib module contains readers and writers of zlib format compressed
 # data, as specified in [RFC 1950](https://www.ietf.org/rfc/rfc1950.txt).
+#
+# NOTE: To use `Zlib` or its children, you must explicitly import it with `require "compress/zlib"`
 module Compress::Zlib
   NO_COMPRESSION      = Compress::Deflate::NO_COMPRESSION
   BEST_SPEED          = Compress::Deflate::BEST_SPEED
diff --git a/src/crypto/bcrypt.cr b/src/crypto/bcrypt.cr
index 28c36bef647c..92d90495c1df 100644
--- a/src/crypto/bcrypt.cr
+++ b/src/crypto/bcrypt.cr
@@ -29,6 +29,8 @@ require "./subtle"
 # Last but not least: beware of denial of services! Always protect your
 # application using an external strategy (eg: rate limiting), otherwise
 # endpoints that verifies bcrypt hashes will be an easy target.
+#
+# NOTE: To use `Bcrypt`, you must explicitly import it with `require "crypto/bcrypt"`
 class Crypto::Bcrypt
   class Error < Exception
   end
diff --git a/src/crypto/bcrypt/password.cr b/src/crypto/bcrypt/password.cr
index 234ac5c1918a..b98658c9e22f 100644
--- a/src/crypto/bcrypt/password.cr
+++ b/src/crypto/bcrypt/password.cr
@@ -3,6 +3,8 @@ require "../subtle"
 
 # Generate, read and verify `Crypto::Bcrypt` hashes.
 #
+# NOTE: To use `Password`, you must explicitly import it with `require "crypto/bcrypt/password"`
+#
 # ```
 # require "crypto/bcrypt/password"
 #
diff --git a/src/csv.cr b/src/csv.cr
index 92fdd4f4dd87..d01da95ff138 100644
--- a/src/csv.cr
+++ b/src/csv.cr
@@ -3,6 +3,8 @@
 #
 # This module conforms to [RFC 4180](https://tools.ietf.org/html/rfc4180).
 #
+# NOTE: To use `CSV` or its children, you must explicitly import it with `require "csv"`
+#
 # ### Parsing
 #
 # Several ways of parsing CSV are provided. The most straight-forward, but
diff --git a/src/digest/adler32.cr b/src/digest/adler32.cr
index 110eb9a8684e..0b31e52a80b1 100644
--- a/src/digest/adler32.cr
+++ b/src/digest/adler32.cr
@@ -2,6 +2,8 @@ require "lib_z"
 require "./digest"
 
 # Implements the Adler32 checksum algorithm.
+#
+# NOTE: To use `Adler32`, you must explicitly import it with `require "digest/adler32"`
 class Digest::Adler32 < ::Digest
   extend ClassMethods
 
diff --git a/src/digest/crc32.cr b/src/digest/crc32.cr
index 07432f455a69..b32ecd68e41f 100644
--- a/src/digest/crc32.cr
+++ b/src/digest/crc32.cr
@@ -2,6 +2,8 @@ require "lib_z"
 require "./digest"
 
 # Implements the CRC32 checksum algorithm.
+#
+# NOTE: To use `CRC32`, you must explicitly import it with `require "digest/crc32"`
 class Digest::CRC32 < ::Digest
   extend ClassMethods
 
diff --git a/src/digest/md5.cr b/src/digest/md5.cr
index 35a4247d0baa..15f74b3e0b95 100644
--- a/src/digest/md5.cr
+++ b/src/digest/md5.cr
@@ -3,6 +3,8 @@ require "openssl"
 
 # Implements the MD5 digest algorithm.
 #
+# NOTE: To use `MD5`, you must explicitly import it with `require "digest/md5"`
+#
 # WARNING: MD5 is no longer a cryptographically secure hash, and should not be
 # used in security-related components, like password hashing. For passwords, see
 # `Crypto::Bcrypt::Password`. For a generic cryptographic hash, use SHA-256 via
diff --git a/src/digest/sha1.cr b/src/digest/sha1.cr
index b777cb55f7fb..01d96ce00bc0 100644
--- a/src/digest/sha1.cr
+++ b/src/digest/sha1.cr
@@ -3,6 +3,8 @@ require "openssl"
 
 # Implements the SHA1 digest algorithm.
 #
+# NOTE: To use `SHA1`, you must explicitly import it with `require "digest/sha1"`
+#
 # WARNING: SHA1 is no longer a cryptographically secure hash, and should not be
 # used in security-related components, like password hashing. For passwords, see
 # `Crypto::Bcrypt::Password`. For a generic cryptographic hash, use SHA-256 via
diff --git a/src/digest/sha256.cr b/src/digest/sha256.cr
index 93606091aca5..4c4cc882b667 100644
--- a/src/digest/sha256.cr
+++ b/src/digest/sha256.cr
@@ -2,6 +2,8 @@ require "./digest"
 require "openssl"
 
 # Implements the SHA256 digest algorithm.
+#
+# NOTE: To use `SHA256`, you must explicitly import it with `require "digest/sha256"`
 class Digest::SHA256 < ::OpenSSL::Digest
   extend ClassMethods
 
diff --git a/src/digest/sha512.cr b/src/digest/sha512.cr
index fe517e7cc2b1..f6364e4db5aa 100644
--- a/src/digest/sha512.cr
+++ b/src/digest/sha512.cr
@@ -2,6 +2,8 @@ require "./digest"
 require "openssl"
 
 # Implements the SHA512 digest algorithm.
+#
+# NOTE: To use `SHA256`, you must explicitly import it with `require "digest/sha512"`
 class Digest::SHA512 < ::OpenSSL::Digest
   extend ClassMethods
 
diff --git a/src/ecr.cr b/src/ecr.cr
index 86ccd035911b..42bee548b22c 100644
--- a/src/ecr.cr
+++ b/src/ecr.cr
@@ -16,6 +16,8 @@
 # tag: `<%# hello %>`. An ECR tag can be inserted directly (i.e. the tag itself may be
 # escaped) by using a second `%` like so: `<%% a = b %>` or `<%%= foo %>`.
 #
+# NOTE: To use `ECR`, you must explicitly import it with `require "ecr"`
+#
 # Quick Example:
 #
 # Create a simple ECR file named `greeter.ecr`:
diff --git a/src/file_utils.cr b/src/file_utils.cr
index 21c3041cfc74..ad189ecd0b25 100644
--- a/src/file_utils.cr
+++ b/src/file_utils.cr
@@ -1,3 +1,4 @@
+# NOTE: To use `FileUtils`, you must explicitly import it with `require "file_utils"`
 module FileUtils
   extend self
 
diff --git a/src/html.cr b/src/html.cr
index 703d3fb47579..49457b1f1e29 100644
--- a/src/html.cr
+++ b/src/html.cr
@@ -3,6 +3,8 @@ require "./html/entities"
 # Provides HTML escaping and unescaping methods.
 #
 # For HTML *parsing* see module XML, especially `XML.parse_html`.
+#
+# NOTE: To use `HTML`, you must explicitly import it with `require "html"`
 module HTML
   private SUBSTITUTIONS = {
     '&'  => "&amp;",
diff --git a/src/http.cr b/src/http.cr
index 4be21ed52404..29dd9faf94b9 100644
--- a/src/http.cr
+++ b/src/http.cr
@@ -5,5 +5,7 @@ require "./http/log"
 require "./http/common"
 
 # The HTTP module contains `HTTP::Client`, `HTTP::Server` and `HTTP::WebSocket` implementations.
+#
+# NOTE: To use `HTTP`, you must explicitly import it with `require "http"`
 module HTTP
 end
diff --git a/src/http/client.cr b/src/http/client.cr
index c9b9e1d699da..41bfa70e68ed 100644
--- a/src/http/client.cr
+++ b/src/http/client.cr
@@ -4,6 +4,8 @@
 
 # An HTTP Client.
 #
+# NOTE: To use `Client`, you must explicitly import it with `require "http/client"`
+#
 # ### One-shot usage
 #
 # Without a block, an `HTTP::Client::Response` is returned and the response's body
diff --git a/src/http/cookie.cr b/src/http/cookie.cr
index 5b672ca2238a..83b41297707e 100644
--- a/src/http/cookie.cr
+++ b/src/http/cookie.cr
@@ -2,6 +2,8 @@ require "./common"
 
 module HTTP
   # Represents a cookie with all its attributes. Provides convenient access and modification of them.
+  #
+  # NOTE: To use `Cookie`, you must explicitly import it with `require "http/cookie"`
   class Cookie
     # Possible values for the `SameSite` cookie as described in the [Same-site Cookies Draft](https://tools.ietf.org/html/draft-west-first-party-cookies-07#section-4.1.1).
     enum SameSite
@@ -273,6 +275,8 @@ module HTTP
 
   # Represents a collection of cookies as it can be present inside
   # a HTTP request or response.
+  #
+  # NOTE: To use `Cookies`, you must explicitly import it with `require "http/cookie"`
   class Cookies
     include Enumerable(Cookie)
 
diff --git a/src/http/formdata.cr b/src/http/formdata.cr
index 433ee494b3de..267442687864 100644
--- a/src/http/formdata.cr
+++ b/src/http/formdata.cr
@@ -4,6 +4,8 @@ require "mime/multipart"
 # Contains utilities for parsing `multipart/form-data` messages, which are
 # commonly used for encoding HTML form data.
 #
+# NOTE: To use `FormData`, you must explicitly import it with `require "http"`
+#
 # ### Examples
 #
 # Commonly, you'll want to parse a from response from a HTTP request, and
diff --git a/src/http/headers.cr b/src/http/headers.cr
index f3ad07d402c5..61e04881c1a9 100644
--- a/src/http/headers.cr
+++ b/src/http/headers.cr
@@ -2,6 +2,8 @@
 #
 # Two headers are considered the same if their downcase representation is the same
 # (in which `_` is the downcase version of `-`).
+#
+# NOTE: To use `Headers`, you must explicitly import it with `require "http/headers"`
 struct HTTP::Headers
   include Enumerable({String, Array(String)})
 
diff --git a/src/http/request.cr b/src/http/request.cr
index 9a01daeab437..c6a72d3469c0 100644
--- a/src/http/request.cr
+++ b/src/http/request.cr
@@ -12,6 +12,8 @@ require "socket"
 # When creating a request with a `String` or `Bytes` its body
 # will be a `IO::Memory` wrapping these, and the `Content-Length`
 # header will be set appropriately.
+#
+# NOTE: To use `Request`, you must explicitly import it with `require "http/request"`
 class HTTP::Request
   property method : String
   property headers : Headers
diff --git a/src/http/server.cr b/src/http/server.cr
index 1a6e7d8d8733..6e44f4150582 100644
--- a/src/http/server.cr
+++ b/src/http/server.cr
@@ -15,6 +15,8 @@ require "log"
 # A server is initialized with a handler chain responsible for processing each
 # incoming request.
 #
+# NOTE: To use `Server`, you must explicitly import it with `require "http/server"`
+#
 # ```
 # require "http/server"
 #
diff --git a/src/http/server/handler.cr b/src/http/server/handler.cr
index 3b1f97113b80..792879fc949d 100644
--- a/src/http/server/handler.cr
+++ b/src/http/server/handler.cr
@@ -4,6 +4,8 @@ require "./context"
 # You can use a handler to intercept any incoming request and can modify the response.
 # These can be used for request throttling, ip-based filtering, adding custom headers e.g.
 #
+# NOTE: To use `Handler`, you must explicitly import it with `require "http/server/handler"`
+#
 # ### A custom handler
 #
 # ```
diff --git a/src/http/server/handlers/compress_handler.cr b/src/http/server/handlers/compress_handler.cr
index 8dd5e66c4404..e059b697649c 100644
--- a/src/http/server/handlers/compress_handler.cr
+++ b/src/http/server/handlers/compress_handler.cr
@@ -5,6 +5,8 @@
 
 # A handler that configures an `HTTP::Server::Response` to compress the response
 # output, either using gzip or deflate, depending on the `Accept-Encoding` request header.
+#
+# NOTE: To use `CompressHandler`, you must explicitly import it with `require "http"`
 class HTTP::CompressHandler
   include HTTP::Handler
 
diff --git a/src/http/server/handlers/error_handler.cr b/src/http/server/handlers/error_handler.cr
index 6036b0d9536e..f92b1a8d0c7a 100644
--- a/src/http/server/handlers/error_handler.cr
+++ b/src/http/server/handlers/error_handler.cr
@@ -6,6 +6,8 @@
 #
 # This handler also logs the exceptions to the specified logger or
 # the logger for the source "http.server" by default.
+#
+# NOTE: To use `ErrorHandler`, you must explicitly import it with `require "http"`
 class HTTP::ErrorHandler
   include HTTP::Handler
 
diff --git a/src/http/server/handlers/log_handler.cr b/src/http/server/handlers/log_handler.cr
index eb29fd7d1595..6aa82f6d911a 100644
--- a/src/http/server/handlers/log_handler.cr
+++ b/src/http/server/handlers/log_handler.cr
@@ -2,6 +2,8 @@ require "log"
 
 # A handler that logs the request method, resource, status code, and
 # the time used to execute the next handler
+#
+# NOTE: To use `LogHandler`, you must explicitly import it with `require "http"`
 class HTTP::LogHandler
   include HTTP::Handler
 
diff --git a/src/http/server/handlers/static_file_handler.cr b/src/http/server/handlers/static_file_handler.cr
index d38b462e7a3e..3fbb57ab0bc0 100644
--- a/src/http/server/handlers/static_file_handler.cr
+++ b/src/http/server/handlers/static_file_handler.cr
@@ -8,6 +8,8 @@ require "mime"
 # This handler can send precompressed content, if the client accepts it, and a file
 # with the same name and `.gz` extension appended is found in the same directory.
 # Precompressed files are only served if they are newer than the original file.
+#
+# NOTE: To use `StaticFileHandler`, you must explicitly import it with `require "http"`
 class HTTP::StaticFileHandler
   include HTTP::Handler
 
diff --git a/src/http/server/handlers/websocket_handler.cr b/src/http/server/handlers/websocket_handler.cr
index c287e91dbb3b..c201f794e909 100644
--- a/src/http/server/handlers/websocket_handler.cr
+++ b/src/http/server/handlers/websocket_handler.cr
@@ -3,6 +3,8 @@ require "http/web_socket"
 
 # A handler which adds websocket functionality to an `HTTP::Server`.
 #
+# NOTE: To use `WebSocketHandler`, you must explicitly import it with `require "http"`
+#
 # When a request can be upgraded, the associated `HTTP::Websocket` and
 # `HTTP::Server::Context` will be yielded to the block. For example:
 #
diff --git a/src/http/status.cr b/src/http/status.cr
index f3920b808e82..a02299f9fed7 100644
--- a/src/http/status.cr
+++ b/src/http/status.cr
@@ -4,6 +4,8 @@
 #
 # It provides constants for the defined HTTP status codes as well as helper
 # methods to easily identify the type of response.
+#
+# NOTE: To use `Status`, you must explicitly import it with `require "http/status"`
 enum HTTP::Status
   CONTINUE                        = 100
   SWITCHING_PROTOCOLS             = 101
diff --git a/src/http/web_socket.cr b/src/http/web_socket.cr
index 9359c6c194bf..823e6b4e2eab 100644
--- a/src/http/web_socket.cr
+++ b/src/http/web_socket.cr
@@ -1,6 +1,8 @@
 require "./client"
 require "./headers"
 
+
+# NOTE: To use `WebSocket`, you must explicitly import it with `require "http/web_socket"`
 class HTTP::WebSocket
   getter? closed = false
 
diff --git a/src/ini.cr b/src/ini.cr
index 39a82dc44894..79d7cd1bcdeb 100644
--- a/src/ini.cr
+++ b/src/ini.cr
@@ -1,3 +1,4 @@
+# NOTE: To use `INI`, you must explicitly import it with `require "ini"`
 module INI
   # Exception thrown on an INI parse error.
   class ParseException < Exception
diff --git a/src/json.cr b/src/json.cr
index a9eae0d8cf99..f55aca854c00 100644
--- a/src/json.cr
+++ b/src/json.cr
@@ -1,5 +1,7 @@
 # The JSON module allows parsing and generating [JSON](http://json.org/) documents.
 #
+# NOTE: To use `JSON` or its children, you must explicitly import it with `require "json"`
+#
 # ### General type-safe interface
 #
 # The general type-safe interface for parsing JSON is to invoke `T.from_json` on a
diff --git a/src/levenshtein.cr b/src/levenshtein.cr
index 571e0ab830e6..e890d59c90ef 100644
--- a/src/levenshtein.cr
+++ b/src/levenshtein.cr
@@ -1,4 +1,6 @@
 # Levenshtein distance methods.
+#
+# NOTE: To use `Levenshtein`, you must explicitly import it with `require "levenshtein"`
 module Levenshtein
   # Computes the [levenshtein distance](http://en.wikipedia.org/wiki/Levenshtein_distance) of two strings.
   #
diff --git a/src/log.cr b/src/log.cr
index 428c8e19fd11..9620a2c56992 100644
--- a/src/log.cr
+++ b/src/log.cr
@@ -7,6 +7,8 @@
 # `#error`, and `#fatal` methods. They expect a block that will evaluate to the
 # message of the entry:
 #
+# NOTE: To use `Log`, you must explicitly import it with `require "log"`
+#
 # ```
 # require "log"
 #
diff --git a/src/mime.cr b/src/mime.cr
index 4e794a803271..ac653e5c9f89 100644
--- a/src/mime.cr
+++ b/src/mime.cr
@@ -2,6 +2,8 @@ require "crystal/system/mime"
 
 # This module implements a global MIME registry.
 #
+# NOTE: To use `MIME`, you must explicitly import it with `require "mime"`
+#
 # ```
 # require "mime"
 #
diff --git a/src/oauth/oauth.cr b/src/oauth/oauth.cr
index 5379ceb1f212..292055cfc777 100644
--- a/src/oauth/oauth.cr
+++ b/src/oauth/oauth.cr
@@ -1,6 +1,8 @@
 # The OAuth module provides an `OAuth::Consumer` as specified by
 # [RFC 5849](https://tools.ietf.org/html/rfc5849).
 #
+# NOTE: To use `OAuth`, you must explicitly import it with `require "oauth"`
+#
 # ### Performing HTTP client requests with OAuth authentication
 #
 # Assuming you have an access token, its secret, the consumer key and the consumer secret,
diff --git a/src/oauth2/oauth2.cr b/src/oauth2/oauth2.cr
index 014e300a8f4e..3a9cde157f39 100644
--- a/src/oauth2/oauth2.cr
+++ b/src/oauth2/oauth2.cr
@@ -1,6 +1,8 @@
 # The OAuth module provides an `OAuth2::Client` as specified
 # by [RFC 6749](https://tools.ietf.org/html/rfc6749).
 #
+# NOTE: To use `OAuth2`, you must explicitly import it with `require "oauth2"`
+#
 # ### Performing HTTP client requests with OAuth2 authentication
 #
 # Assuming you have an access token, you can setup an `HTTP::Client`
diff --git a/src/openssl.cr b/src/openssl.cr
index 71086e577df6..802c9a05e7d3 100644
--- a/src/openssl.cr
+++ b/src/openssl.cr
@@ -1,6 +1,8 @@
 require "./openssl/lib_ssl"
 require "./openssl/error"
 
+# NOTE: To use `OpenSSL`, you must explicitly import it with `require "openssl"`
+#
 # ## OpenSSL Integration
 #
 # - TLS sockets need a context, potentially with keys (required for servers) and configuration.
diff --git a/src/option_parser.cr b/src/option_parser.cr
index 175926a8c730..5f61e73cd58d 100644
--- a/src/option_parser.cr
+++ b/src/option_parser.cr
@@ -7,6 +7,8 @@
 #
 # Run `crystal` for an example of a CLI built with `OptionParser`.
 #
+# NOTE: To use `OptionParser`, you must explicitly import it with `require "option_parser"`
+#
 # Short example:
 #
 # ```
diff --git a/src/socket/ip_socket.cr b/src/socket/ip_socket.cr
index 2f98063645b1..918b4d2b8591 100644
--- a/src/socket/ip_socket.cr
+++ b/src/socket/ip_socket.cr
@@ -1,3 +1,4 @@
+# NOTE: To use `IPSocket`, you must explicitly import it with `require "socket/ip_socket"`
 class IPSocket < Socket
   # Returns the `IPAddress` for the local end of the IP socket.
   getter local_address : Socket::IPAddress { system_local_address }
diff --git a/src/socket/tcp_server.cr b/src/socket/tcp_server.cr
index 51d828d45426..c5cf3e1fcef0 100644
--- a/src/socket/tcp_server.cr
+++ b/src/socket/tcp_server.cr
@@ -2,6 +2,8 @@ require "./tcp_socket"
 
 # A Transmission Control Protocol (TCP/IP) server.
 #
+# NOTE: To use `TCPServer`, you must explicitly import it with `require "socket"`
+#
 # Usage example:
 # ```
 # require "socket"
diff --git a/src/socket/tcp_socket.cr b/src/socket/tcp_socket.cr
index 980f0b338cff..06e3d6f9b138 100644
--- a/src/socket/tcp_socket.cr
+++ b/src/socket/tcp_socket.cr
@@ -2,6 +2,8 @@ require "./ip_socket"
 
 # A Transmission Control Protocol (TCP/IP) socket.
 #
+# NOTE: To use `TCPSocket`, you must explicitly import it with `require "socket"`
+#
 # Usage example:
 # ```
 # require "socket"
diff --git a/src/socket/udp_socket.cr b/src/socket/udp_socket.cr
index 3e9cebe0a01d..86132c54d0c7 100644
--- a/src/socket/udp_socket.cr
+++ b/src/socket/udp_socket.cr
@@ -15,6 +15,8 @@ require "./ip_socket"
 # This implementation supports both IPv4 and IPv6 addresses. For IPv4 addresses you must use
 # `Socket::Family::INET` family (default) or `Socket::Family::INET6` for IPv6 # addresses.
 #
+# NOTE: To use `UDPSocket`, you must explicitly import it with `require "socket"`
+#
 # Usage example:
 #
 # ```
diff --git a/src/socket/unix_server.cr b/src/socket/unix_server.cr
index 98425e86cc54..e53f71d00842 100644
--- a/src/socket/unix_server.cr
+++ b/src/socket/unix_server.cr
@@ -4,6 +4,8 @@ require "./unix_socket"
 #
 # Only available on UNIX and UNIX-like operating systems.
 #
+# NOTE: To use `UNIXServer`, you must explicitly import it with `require "socket"`
+#
 # Example usage:
 # ```
 # require "socket"
diff --git a/src/socket/unix_socket.cr b/src/socket/unix_socket.cr
index 6a4dbb3d340a..16ad99700db4 100644
--- a/src/socket/unix_socket.cr
+++ b/src/socket/unix_socket.cr
@@ -2,6 +2,8 @@
 #
 # Only available on UNIX and UNIX-like operating systems.
 #
+# NOTE: To use `UNIXSocket`, you must explicitly import it with `require "socket"`
+#
 # Example usage:
 # ```
 # require "socket"
diff --git a/src/string_pool.cr b/src/string_pool.cr
index 03b4246a3e0c..448196bcf622 100644
--- a/src/string_pool.cr
+++ b/src/string_pool.cr
@@ -2,6 +2,8 @@
 # It allows a runtime to save memory by preserving strings in a pool, allowing to
 # reuse an instance of a common string instead of creating a new one.
 #
+# NOTE: To use `StringPool`, you must explicitly import it with `require "string_pool"`
+#
 # ```
 # require "string_pool"
 #
diff --git a/src/string_scanner.cr b/src/string_scanner.cr
index b79725a9c354..c679f8de46d7 100644
--- a/src/string_scanner.cr
+++ b/src/string_scanner.cr
@@ -1,5 +1,7 @@
 # `StringScanner` provides for lexical scanning operations on a `String`.
 #
+# NOTE: To use `StringScanner`, you must explicitly import it with `require "string_scanner"`
+#
 # ### Example
 #
 # ```
diff --git a/src/system/group.cr b/src/system/group.cr
index 47c43ccee1ac..bd992e6af19d 100644
--- a/src/system/group.cr
+++ b/src/system/group.cr
@@ -2,6 +2,8 @@ require "crystal/system/group"
 
 # Represents a group of users on the host system.
 #
+# NOTE: To use Group, you must explicitly import it with `require "system/group"`
+#
 # Groups can be retrieved by either group name or their group ID:
 #
 # ```
diff --git a/src/system/user.cr b/src/system/user.cr
index 2d0c9607056d..f23e13e6dc4c 100644
--- a/src/system/user.cr
+++ b/src/system/user.cr
@@ -2,6 +2,8 @@ require "crystal/system/user"
 
 # Represents a user on the host system.
 #
+# NOTE: To use User, you must explicitly import it with `require "system/user"`
+#
 # Users can be retrieved by either username or their user ID:
 #
 # ```
diff --git a/src/uri.cr b/src/uri.cr
index 36a407e1d35b..06842deadf6d 100644
--- a/src/uri.cr
+++ b/src/uri.cr
@@ -9,6 +9,8 @@ require "./uri/params"
 # their components or by parsing their string forms and methods for accessing the various
 # components of an instance.
 #
+# NOTE: To use `URI`, you must explicitly import it with `require "uri"`
+#
 # Basic example:
 #
 # ```
diff --git a/src/uuid.cr b/src/uuid.cr
index 2146c26b43bb..7c8d44478f84 100644
--- a/src/uuid.cr
+++ b/src/uuid.cr
@@ -1,4 +1,6 @@
 # Represents a UUID (Universally Unique IDentifier).
+#
+# NOTE: To use `UUID`, you must explicitly import it with `require "uuid"`
 struct UUID
   include Comparable(UUID)
 
diff --git a/src/weak_ref.cr b/src/weak_ref.cr
index 103aedd30e7c..b5f7468383d0 100644
--- a/src/weak_ref.cr
+++ b/src/weak_ref.cr
@@ -1,6 +1,7 @@
 # Weak Reference class that allows a referenced object to be garbage-collected.
 #
 # WARNING: The referenced object cannot be a module.
+# NOTE: To use `WeakRef`, you must explicitly import it with `require "weak_ref"`
 #
 # ```
 # require "weak_ref"
diff --git a/src/xml.cr b/src/xml.cr
index 9e1a19e4cc7c..1f0085fcd063 100644
--- a/src/xml.cr
+++ b/src/xml.cr
@@ -1,5 +1,7 @@
 # The XML module allows parsing and generating [XML](https://www.w3.org/XML/) documents.
 #
+# NOTE: To use `XML`, you must explicitly import it with `require "xml"`
+#
 # ### Parsing
 #
 # `XML#parse` will parse xml from `String` or `IO` and return xml document as an `XML::Node` which represents all kinds of xml nodes.
diff --git a/src/yaml.cr b/src/yaml.cr
index 23a5843dfecb..c9ecb746ee69 100644
--- a/src/yaml.cr
+++ b/src/yaml.cr
@@ -10,6 +10,8 @@ require "base64"
 # version 1.1 to/from native Crystal data structures, with the additional
 # independent types specified in http://yaml.org/type/
 #
+# NOTE: To use `YAML`, you must explicitly import it with `require "yaml"`
+#
 # ### Parsing with `#parse` and `#parse_all`
 #
 # `YAML.parse` will return an `Any`, which is a convenient wrapper around all possible