Answer product-owner round 1: the hint for an empty stdin points to --list, the help's examples are templates only, the README's record id is an integer, and a test over an indexed module renders each path

README.md

@@ -352,7 +352,7 @@ v = t.Fake()                                              // render many times,
 r, err := f.FakeRecord("users")           // one record: each field a column
 s := r.JSON()                             // {"first":"Ada","last":"Lovelace"}
 r, err = f.FakeRecordTemplate(`{"format":"{x}","x":["a","b"]}`) // compile + render inline
-rt, err := f.NewRecordTemplate(`{"format":"","id":"{seq(users)}"}`) // compile a record once
+rt, err := f.NewRecordTemplate(`{"format":"","id":{"format":"{seq(users)}","datatype":"integer"}}`) // compile once
 r = rt.Fake()                             // render a row; loop this for bulk output
 err = f.FakeStruct(&user)                 // fill a struct's fake:"…" tagged fields
 ok, err := fejkdata.IsTemplate(arg)       // an inline template by its shape, else a path
@@ -459,7 +459,8 @@ func main() { os.Exit(cli.Main(append(data.Modules(), mydata)...)) }
 The embed's folders are the paths: `//go:embed acme` serves `acme/customer.json` as
 `{/acme.customer}`. Add `*.tsv` to the embed where your data holds a table. The CLI loads
 its data when it runs, so a test calling `fejkdata.New(fejkdata.WithDataFS(...))` over the
-same modules catches broken data at `go test`. The CLI takes `fejkdata`'s flags
+same modules, rendering each path once where a module carries an index, catches broken
+data at `go test`. The CLI takes `fejkdata`'s flags
 and exit codes, and names itself by the file it runs from in its help and errors. `--no-shipped-data` leaves out the modules passed to `Main`, and
 `--version` prints your module's version beside the fejkdata version it is built with.