A tag write past the limit is refused whole, naming it

A write to tag longer than the room left was cut and applied in part. It now changes nothing and fails ENOSPC, tag: over 4096 bytes; the docs give the limit.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 3 insertions, 1 deletions

diff --git a/docs/fs.md b/docs/fs.md
index f3602dfc..f35bb3f6 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -806,7 +806,9 @@ a command pane ends in its own time, told by its `exit` record.
 page (no mark for unsaved text: the grip shows that, and `dirty` says it),
 then the text you may edit. An image's tag begins with its mode words, not
 its path: `img petscii:off palette:commodore ascii:on <path>` by default, the modes
-it is drawn in, then the file. A write appends to that text,
+it is drawn in, then the file. The editable text is 4096 bytes at most: a
+write that would pass that is refused whole, ENOSPC, `tag: over 4096
+bytes`. A write appends to that text,
 newlines included, and a tag with more than one line takes a row per line on
 screen; truncating `tag` clears it, as acme's `cleartag` does -- the default
 words (`Save Tty Collapse Del` and the rest) with it, since they are that text until