diff --git a/Cargo.toml b/Cargo.toml
index b15eed77..3b7aa63f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,6 +6,10 @@ all = { level = "allow", priority = -2 }
 correctness = { level = "warn", priority = -1 }
 complexity = { level = "warn", priority = -1 }
 
+[workspace.lints.rust]
+missing_docs = "warn"
+rust_2018_idioms = "warn"
+
 [package]
 name = "mdbook"
 version = "0.4.52"
diff --git a/examples/nop-preprocessor.rs b/examples/nop-preprocessor.rs
index a384dfda..ae593afc 100644
--- a/examples/nop-preprocessor.rs
+++ b/examples/nop-preprocessor.rs
@@ -1,3 +1,5 @@
+//! A basic example of a preprocessor that does nothing.
+
 use crate::nop_lib::Nop;
 use clap::{Arg, ArgMatches, Command};
 use mdbook::book::Book;
@@ -7,7 +9,7 @@ use semver::{Version, VersionReq};
 use std::io;
 use std::process;
 
-pub fn make_app() -> Command {
+fn make_app() -> Command {
     Command::new("nop-preprocessor")
         .about("A mdbook preprocessor which does precisely nothing")
         .subcommand(
diff --git a/examples/remove-emphasis/test.rs b/examples/remove-emphasis/test.rs
index 1741712b..e29d7d0f 100644
--- a/examples/remove-emphasis/test.rs
+++ b/examples/remove-emphasis/test.rs
@@ -1,3 +1,5 @@
+//! A test to ensure that the remove-emphasis example works.
+
 #[test]
 fn remove_emphasis_works() {
     // Tests that the remove-emphasis example works as expected.
diff --git a/src/config.rs b/src/config.rs
index 7ef8bcef..3fe16929 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -47,8 +47,6 @@
 //! # run().unwrap()
 //! ```
 
-#![deny(missing_docs)]
-
 use log::{debug, trace, warn};
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use std::collections::HashMap;
diff --git a/src/lib.rs b/src/lib.rs
index 8a8cb3c9..5f521761 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -80,9 +80,6 @@
 //! [relevant chapter]: https://rust-lang.github.io/mdBook/for_developers/backends.html
 //! [`Config`]: config::Config
 
-#![deny(missing_docs)]
-#![deny(rust_2018_idioms)]
-
 pub mod book;
 pub mod config;
 pub mod preprocess;
diff --git a/src/main.rs b/src/main.rs
index 3e576c5b..975b5a21 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,5 @@
+//! The mdbook CLI.
+
 #[macro_use]
 extern crate clap;
 #[macro_use]
diff --git a/tests/gui/runner.rs b/tests/gui/runner.rs
index 3177ff4f..b8d4bacc 100644
--- a/tests/gui/runner.rs
+++ b/tests/gui/runner.rs
@@ -1,3 +1,9 @@
+//! The GUI test runner.
+//!
+//! This uses the browser-ui-test npm package to use a headless Chrome to
+//! exercise the behavior of rendered books. See `CONTRIBUTING.md` for more
+//! information.
+
 use serde_json::Value;
 use std::collections::HashSet;
 use std::env::current_dir;