diff --git a/tools/common.zig b/tools/common.zig
index 5577974d..408aaaf0 100644
--- a/tools/common.zig
+++ b/tools/common.zig
@@ -142,13 +142,15 @@ pub fn printUsage() void {
         \\{s} — offline S-57 -> PMTiles baker / inspector
         \\
         \\usage:
-        \\  tile57 bake <cell.000 | ENC_ROOT | chart.KAP | BSB_ROOT> -o <out-dir> [--rules DIR] [-j N]
+        \\  tile57 bake <cell.000 | ENC_ROOT | chart.KAP | BSB_ROOT> -o <out-dir> [--rules DIR] [-j N] [--no-aux]
         \\      Produce a live-composite structure: bake each chart (a single .000 +
         \\      its auto-discovered updates, OR every <CELL>.000 in an ENC_ROOT, at
-        \\      native band scale) to its own <out>/tiles/<STEM>.pmtiles with M_COVR
-        \\      coverage embedded, then write the ownership partition to
-        \\      <out>/partition.tpart. A runtime compositor (compose-tile / the C ABI)
-        \\      serves any tile ON DEMAND from this structure — there is no merged archive.
+        \\      native band scale) to its own directory, <out>/<STEM>/<STEM>.pmtiles,
+        \\      with M_COVR coverage embedded and a .sha content hash beside it, then
+        \\      write the ownership partition to <out>/partition.tpart. The text and
+        \\      pictures a chart references travel in that chart's directory. A runtime
+        \\      compositor (compose-tile / the C ABI) serves any tile ON DEMAND from
+        \\      this structure — there is no merged archive.
         \\      A .KAP sheet or a BSB_ROOT of them bakes the same structure with PNG
         \\      tiles, clipped to each sheet's PLY border and carrying its scale and
         \\      edition date. One bake writes one kind of library.
@@ -156,6 +158,8 @@ pub fn printUsage() void {
         \\      --rules DIR         S-101 portrayal rules directory (default: embedded)
         \\      -j, --workers N     bake threads (default: min(cores/2, 8)). A MEMORY
         \\                          bound: each worker holds a whole cell's working set.
+        \\      --no-aux            bake the charts alone, without the text and
+        \\                          pictures they reference.
         \\
     , .{VERSION});
 }