diff --git a/GEMINI.md b/GEMINI.md
index 2334d7b9..9ac25612 100644
--- a/GEMINI.md
+++ b/GEMINI.md
@@ -79,7 +79,9 @@ list of options.
   project tools with `cargo xtask install-tools`.
 - **Contributions:** Refer to `CONTRIBUTING.md` for guidelines on contributing
   to the project.
-- **Style:** Refer to `STYLE.md` for style guidelines.
+- **Style:** Refer to `STYLE.md` for style guidelines. When making changes to
+  Markdown files in `src/`, always first read `STYLE.md` and follow its
+  conventions.
 - **GitHub Actions:** The project uses composite GitHub Actions to simplify CI
   workflows. These actions should be preferred over hand-written commands.
   - **`apt-get-install`:** This action efficiently installs Debian packages. It
@@ -168,7 +170,3 @@ its tasks correctly.
   snippet, treat it as a self-contained program. Do not assume it shares a scope
   or context with other snippets in the same file unless the surrounding text
   explicitly states otherwise.
-- **Interpreting Annotations:** Annotations like `compile_fail`, `should_panic`,
-  and `editable` describe how a snippet is tested. For example, `compile_fail`
-  means the snippet is expected to fail compilation, which is useful for
-  demonstrating common errors.
diff --git a/STYLE.md b/STYLE.md
index 9d4accdf..d2c0d786 100644
--- a/STYLE.md
+++ b/STYLE.md
@@ -161,11 +161,36 @@ Contributors should design their slides with this interactivity in mind. The
 initial state of the code should be a good starting point for a live
 demonstration.
 
-#### Code Annotations
+### Code Blocks
 
-Use the `ignore` annotation for code snippets that are not meant to be complete,
-self-contained programs. Use `compile_fail` only when the goal is to demonstrate
-a specific compiler error that is itself the lesson.
+Code blocks are a critical part of the course. To ensure they are consistent and
+behave as expected, please follow these conventions.
+
+#### Language Identifiers
+
+Use the following language identifiers for fenced code blocks:
+
+- **`rust`**: For Rust code examples.
+- **`shell`**: For shell commands. Use a `$` prompt for consistency. Omit the
+  prompt for multi-line commands or when the output is shown.
+- **`bob`**: For ASCII art diagrams generated by `mdbook-bob`.
+- **`ignore`**: For code snippets that are not complete, self-contained programs
+  or are for illustrative purposes only and should not be compiled.
+
+#### mdbook Annotations
+
+You can add annotations to Rust code blocks to control how they are tested and
+displayed:
+
+- **`editable`**: Makes the code block an interactive playground where users can
+  edit and run the code. This should be used for most Rust examples.
+- **`compile_fail`**: Indicates that the code is expected to fail compilation.
+  This is used to demonstrate specific compiler errors.
+- **`should_panic`**: Indicates that the code is expected to panic when run.
+- **`warnunused`**: Re-enables `unused` lints for a code block. By default, the
+  course's test runner disables lints for unused variables, imports, etc., to
+  avoid distracting warnings. Use this annotation only when a warning is part of
+  the lesson.
 
 ### Language and Tone