A root commands file lists every builtin, its argument and which ctl takes it

A script could learn the builtin words only from source or the Help
window. /commands is generated from the registry: one line per builtin,
Word or Word arg, then root or pane for the ctl that takes it, so it is
always this build's own list.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/docs/fs.md b/docs/fs.md
index b3f3cb45..b97f34fa 100644
--- a/docs/fs.md
+++ b/docs/fs.md
@@ -82,6 +82,7 @@ Existing Plan9port/v9fs clients need a userspace bridge for QUIC.
 /listeners   the session's dial addresses
 /focus       the serial of the pane with the keyboard; write a serial to give it the keyboard
 /ctl         the settings, one a line as a write takes them; write a setting or a session builtin
+/commands    every builtin: word, `arg` if it takes one, and `root` or `pane`, the ctl that takes it
 /pane/new    open it to make a pane; the read answers that pane's serial
 /pane/<n>/   name body tag ctl addr dot limit data xdata sel dirty mark scroll
              errors event look exec, plus pty/{ctl,status,data} on terminals
@@ -116,6 +117,11 @@ though a click on the same word written to `exec` still opens it. Like any
 write, a ctl write answers once the editor has performed what it asked for
 (a save written, a shell started).
 
+`/commands` lists every builtin the registry holds, in registry order, one
+a line: its word, `arg` when it takes one, and `root` or `pane` for the ctl
+that takes it, e.g. `Newcol root`, `Save arg pane`, `Verbose arg root`. It is
+generated from the registry, so it is always this build's own list.
+
 `/focus` reads the serial of the pane with the keyboard, and a serial written
 to it gives that pane the keyboard, off any column or workspace tag that had
 it -- rio's `current` written to a window's `wctl`, named once for the whole