diff --git a/tsc/internal/format/README.md b/tsc/internal/format/README.md
index d1086eaa0b485..82765e256f091 100644
--- a/tsc/internal/format/README.md
+++ b/tsc/internal/format/README.md
@@ -17,9 +17,9 @@ node the covers the span of text and recurses down through the node's children.
 As it recurses, `processNode` is called on the children setting the indentation is decided and passed 
 through into each of that node's children.
 
-The meat of formatting decisions is made via `processPair`, the pair here being the current node and the previous node. `processPair` which mutates the formatting context to represent the current place in the scanner and requests a set of rules which can be applied to the items via `createRulesMap`.
+The meat of formatting decisions is made via `processPair`, the pair here being the current node and the previous node. `processPair` which mutates the formatting context to represent the current place in the scanner and requests a set of rules which can be applied to the items via `getRules`, from the map `buildRulesMap` builds once.
 
-There are a lot of rules, which you can find in [rules.ts](./rules.ts) each one has a left and right reference to nodes or token ranges and note of what action should be applied by the formatter.
+There are a lot of rules, which you can find in [rules.go](./rules.go) each one has a left and right reference to nodes or token ranges and note of what action should be applied by the formatter.
 
 ### Where is this used?
 
diff --git a/tsc/internal/format/readme_test.go b/tsc/internal/format/readme_test.go
new file mode 100644
index 0000000000000..a47bc951bfbda
--- /dev/null
+++ b/tsc/internal/format/readme_test.go
@@ -0,0 +1,105 @@
+package format_test
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"testing"
+)
+
+var (
+	readmeLinkRe = regexp.MustCompile(`\]\(([^)#\s]+)(?:#[^)]*)?\)`)
+	readmeCodeRe = regexp.MustCompile("`([^`]+)`")
+	identRe      = regexp.MustCompile(`^[A-Za-z_][A-Za-z0-9_]*\*?$`)
+)
+
+// TestReadmeMatchesCode checks that README.md in this package does not refer to
+// files or identifiers that no longer exist, such as names left over from the
+// TypeScript 6 code base.
+func TestReadmeMatchesCode(t *testing.T) {
+	t.Parallel()
+
+	content, err := os.ReadFile("README.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+	readme := string(content)
+
+	for _, m := range readmeLinkRe.FindAllStringSubmatch(readme, -1) {
+		target := m[1]
+		if strings.Contains(target, "://") {
+			continue
+		}
+		if _, err := os.Stat(filepath.FromSlash(target)); err != nil {
+			t.Errorf("README.md links to %q, which does not exist", target)
+		}
+	}
+
+	names := packageNames(t)
+	for _, m := range readmeCodeRe.FindAllStringSubmatch(readme, -1) {
+		name := m[1]
+		if !identRe.MatchString(name) {
+			continue
+		}
+		if !names.has(name) {
+			t.Errorf("README.md mentions `%s`, which is not declared or used in this package", name)
+		}
+	}
+}
+
+type nameSet map[string]struct{}
+
+// has reports whether name is in the set. A trailing "*" matches any name with that prefix.
+func (s nameSet) has(name string) bool {
+	if prefix, ok := strings.CutSuffix(name, "*"); ok {
+		for n := range s {
+			if strings.HasPrefix(n, prefix) {
+				return true
+			}
+		}
+		return false
+	}
+	_, ok := s[name]
+	return ok
+}
+
+// packageNames collects the names declared in this package's non-test files,
+// along with the names it uses from other packages (such as ast.SourceFile).
+func packageNames(t *testing.T) nameSet {
+	t.Helper()
+	files, err := filepath.Glob("*.go")
+	if err != nil {
+		t.Fatal(err)
+	}
+	names := nameSet{}
+	fset := token.NewFileSet()
+	for _, file := range files {
+		if strings.HasSuffix(file, "_test.go") {
+			continue
+		}
+		f, err := parser.ParseFile(fset, file, nil, parser.SkipObjectResolution)
+		if err != nil {
+			t.Fatal(err)
+		}
+		ast.Inspect(f, func(n ast.Node) bool {
+			switch n := n.(type) {
+			case *ast.FuncDecl:
+				names[n.Name.Name] = struct{}{}
+			case *ast.TypeSpec:
+				names[n.Name.Name] = struct{}{}
+			case *ast.ValueSpec:
+				for _, id := range n.Names {
+					names[id.Name] = struct{}{}
+				}
+			case *ast.SelectorExpr:
+				names[n.Sel.Name] = struct{}{}
+			}
+			return true
+		})
+	}
+	return names
+}