diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 5939a4d..30f7f89 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -45,6 +45,6 @@ repos:
     rev: v0.5.2
     hooks:
       - id: beman-tidy
-        args: [".", "--verbose"]
+        args: [".", "--verbose", "--require-all"]
 
 exclude: 'infra/|port/'
diff --git a/README.md b/README.md
index edfed49..eec747a 100644
--- a/README.md
+++ b/README.md
@@ -7,9 +7,12 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 <!-- markdownlint-disable-next-line line-length -->
 [![Library Status](https://raw.githubusercontent.com/bemanproject/beman/refs/heads/main/images/badges/beman_badge-beman_library_under_development.svg)](https://github.com/bemanproject/beman/blob/main/docs/beman_library_maturity_model.md#the-beman-library-maturity-model) ![Continuous Integration Tests](https://github.com/bemanproject/span/actions/workflows/ci_tests.yml/badge.svg) ![Lint Check (pre-commit)](https://github.com/bemanproject/span/actions/workflows/pre-commit-check.yml/badge.svg) [![Coverage](https://coveralls.io/repos/github/bemanproject/span/badge.svg?branch=main)](https://coveralls.io/github/bemanproject/span?branch=main) ![Standard Target](https://github.com/bemanproject/beman/blob/main/images/badges/cpp29.svg)
 
+[![Compiler Explorer Example](https://img.shields.io/badge/Try%20it%20on%20Compiler%20Explorer-grey?logo=compilerexplorer&logoColor=67c52a)](https://godbolt.org/z/4vsvzbf7z)
+
 `beman.span` is an implementation of various proposed updates to `std::span`.
 
-**Implements:** `std::span` a non-owning view over a contiguous sequence of objects.
+**Implements**: `std::span::at()` proposed in [span.at() (P2821R5)](https://wg21.link/P2821R5).
+
 See [cppreference — std::span](https://en.cppreference.com/w/cpp/container/span) and
 [eel.is/c++draft/views.span](https://eel.is/c++draft/views.span).