diff --git a/.github/instructions/cpp.instructions.md b/.github/instructions/cpp.instructions.md
index cabb855b7..435664c84 100644
--- a/.github/instructions/cpp.instructions.md
+++ b/.github/instructions/cpp.instructions.md
@@ -56,6 +56,10 @@ This project follows a consistent modern C++ style, inspired by Google/LLVM with
 
 ## Naming
 
+Prefer American spelling in identifiers (files, functions, variables) for new
+code and for anything not tied to an existing API. Leave legacy public-API
+names that already use British spelling unchanged (for example `AnalysePlay*`).
+
 ### Types
 - **PascalCase**
 - Examples: `FixedArray`, `ErrorCode`, `SimulationRunner`
diff --git a/AGENTS.md b/AGENTS.md
index 6d70dc4bc..f63220fe1 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -10,8 +10,11 @@ Follow .github/instructions/cpp.instructions.md
 
 Follow .github/instructions/cpp.instructions.md
 
+Prefer American spelling in file, function, and variable names for new code
+and for anything not tied to an existing API.
+
 Exceptions:
-- Match existing external or legacy APIs (for example, public C API names and types that already use a different style).
+- Match existing external or legacy APIs (for example, public C API names and types that already use a different style, such as `AnalysePlay*`).
 - Do not rename unrelated legacy identifiers in the same change unless the task requires it.
 
 # Test-driven development
diff --git a/examples/README b/examples/README
index 477ef9fa8..f0176c3b2 100644
--- a/examples/README
+++ b/examples/README
@@ -28,7 +28,7 @@ Run an example:
 
 Available examples:
 - analyse_all_plays_bin, analyse_all_plays_pbn
-- analyse_play_bin, analyse_play_pbn
+- AnalysePlayBin (source `analyse_play_bin.cpp`), analyse_play_pbn
 - calc_all_tables, calc_all_tables_pbn
 - calc_dd_table, calc_dd_table_pbn
 - dd_table_for_deal (C++; Python: //python/examples:dd_table_for_deal; .NET: dotnet/DdTableForDeal)