diff --git a/COMPILING.md b/COMPILING.md
index 18d88ce1..e74861ad 100644
--- a/COMPILING.md
+++ b/COMPILING.md
@@ -17,7 +17,7 @@
 >
 > ```bash
 > # one-time bootstrap: clang assembles the seed, then ludicc compiles bin/x
-> clang selfhost/ludicc.seed.ll -o bin/ludicc && bin/ludicc tools/x/main.ludic -o bin/x
+> mkdir -p bin && clang selfhost/ludicc.seed.ll -o bin/ludicc && bin/ludicc tools/x/main.ludic -o bin/x
 > bin/x build                             # rebuild the whole toolchain into bin/
 >                                         #   (ludicc, ludic, x, ludic-fmt, ludic-lsp)
 > bin/ludicc examples/games/snake.ludic -o bin/snake   # compile
diff --git a/README.md b/README.md
index bf550cc4..ee6e88b5 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,7 @@ Bootstrap it once from a clean checkout (the only step Ludic can't do for
 itself, since compiling Ludic needs a compiler) with clang alone:
 
 ```bash
-clang selfhost/ludicc.seed.ll -o bin/ludicc && bin/ludicc tools/x/main.ludic -o bin/x
+mkdir -p bin && clang selfhost/ludicc.seed.ll -o bin/ludicc && bin/ludicc tools/x/main.ludic -o bin/x
 ```
 
 Then build the whole toolchain and run a game:
diff --git a/changes/bootstrap-mkdir-bin.md b/changes/bootstrap-mkdir-bin.md
new file mode 100644
index 00000000..3e7ec1e8
--- /dev/null
+++ b/changes/bootstrap-mkdir-bin.md
@@ -0,0 +1,7 @@
+bump: patch
+type: fix
+The documented bootstrap works on a fresh clone. `bin/` is gitignored and not
+checked in, so `clang selfhost/ludicc.seed.ll -o bin/ludicc` — the first command
+in the README, in COMPILING, in CONTRIBUTING and on the site — failed with
+`ld: open() failed, errno=2 for 'bin/ludicc'`. Every copy now begins with
+`mkdir -p bin`, which is what CI had been doing all along.