Cut the comments the README already records, and record the cycle-fence and exit-code rules there

README.md

@@ -386,6 +386,15 @@ tokens add cost in proportion to the output.
   instead of a leading-position special case. The JSON string is what makes the
   library's own advice reachable: the error for an object holding only a format
   names `"…"`, and that spelling has to work where it is printed.
+- **An inline template skips the cycle fence, and only that one.** `New` proves the
+  loaded tree acyclic, an inline node is a finite tree of its own, and nothing in
+  the tree can reference it, so no render of it reaches itself. Every other fence
+  runs over both, from one `checkScope`.
+- **An inline template that does not compile is misuse (exit 2), including a
+  reference that resolves to nothing** — the whole argument is the spelling under
+  test, and `NewTemplate` compiles, links and validates as one step. An unknown
+  *path* stays a runtime error (exit 1): there the argument is well-formed and only
+  the data is absent.
 - **A padded JSON argument is rejected, not trimmed.** Padding is the one place the
   two readings disagree — a format string renders it, JSON drops it — so the
   spelling that renders is named rather than silently chosen.

cmd/fejkdata/main.go

@@ -270,11 +270,8 @@ const (
 	argTemplate
 )
 
-// classify reads what a positional argument names by its shape: a format string
+// classify reads what a positional argument names by its shape: a { token, or a
-// carrying a { token, or a JSON object, array or string, is an inline template;
+// JSON object, array or string, is an inline template; anything else is a path.
-// anything else is a path. A name may hold neither a brace nor a bracket nor a
-// quote, so no path collides with any of those spellings, and the JSON gate is
-// valid-JSON so a copied bracket names nothing rather than swallowing an argument.
 func classify(arg string) (argKind, error) {
 	if strings.ContainsRune(arg, '{') || (isJSONStart(strings.TrimSpace(arg)) && json.Valid([]byte(arg))) {
 		return argTemplate, nil

graph.go

@@ -20,7 +20,7 @@ func walkNodes(root map[string]node, fn func(path string, n node) error) error {
 
 // eachNode visits n and every node contained within it once, passing the dot path
 // that reaches each. It never crosses a reference edge — a bound {/path} field is
-// skipped, as in walkNodes — so a single inline node is walked on its own.
+// skipped — so a single inline node is walked on its own.
 func eachNode(n node, path string, fn func(path string, n node) error) error {
 	seen := map[node]bool{}
 	var visit func(string, node) error

inline.go

@@ -27,10 +27,6 @@ func (t *Template) Fake() string {
 // binds its references against the loaded tree, so repeated renders pay the
 // compile and validation once. It shares [New]'s guarantees: a bad template errors
 // here, and rendering cannot fail.
-//
-// checkNoCycles is the one fence loadData runs that an inline node does not need:
-// the loaded tree is proven acyclic at [New], the node is a finite tree, and no
-// tree node can reference it, so nothing it renders can reach itself.
 func (f *Generator) NewTemplate(input string) (*Template, error) {
 	n, err := compileInput(input)
 	if err != nil {
@@ -58,12 +54,7 @@ func (f *Generator) FakeTemplate(input string) (string, error) {
 }
 
 // compileInput compiles an inline template: a JSON value, or a bare format string
-// when the input is not JSON. A JSON string literal and a bare string compile
+// when the input is not JSON.
-// alike (both are a template with no fields); the other JSON scalars — a number,
-// bool or null — are no template, so they are rejected here, as a data file that
-// was one would be at load. Padding is where the two readings would disagree — a
-// format string renders it, JSON drops it — so a padded JSON value is rejected
-// naming the one that renders.
 func compileInput(input string) (node, error) {
 	var raw any
 	if err := json.Unmarshal([]byte(input), &raw); err != nil {
@@ -76,8 +67,7 @@ func compileInput(input string) (node, error) {
 }
 
 // linkNodeRefs binds the references in an inline node's templates against the
-// loaded tree. An inline template sits in no folder, so . and .. name nothing and
+// loaded tree.
-// are rejected for the root spelling they would otherwise silently mean.
 func linkNodeRefs(scope nodeScope, root map[string]node) error {
 	return scope(func(path string, m node) error {
 		t, ok := m.(*template)

node.go

@@ -302,7 +302,7 @@ func repeatOf(m map[string]any) (int, error) {
 	if r == 1 {
 		return 0, fmt.Errorf("repeat 1 is the default, so it has no effect; drop it")
 	}
-	if r > MaxRepeat { // caps the renders one repeat asks for; checkRepeatReach bounds what nested ones multiply to
+	if r > MaxRepeat { // caps the renders one repeat asks for; repeatCheck bounds what nested ones multiply to
 		return 0, fmt.Errorf("repeat %v exceeds the maximum %d", rv, MaxRepeat)
 	}
 	return int(r), nil