feat(cli): chat — read a group's last messages, post one

chat GROUP prints the last ten messages, oldest first (-N, as head -N, or
-n N for another count, paging back past the node's 200), and -m posts one
(- reads it from stdin). The application's construction: every epoch key
from chat_keys_req, a post sealed under the current epoch through the
device subkey and signed with this machine's key on the node, the sender's
name inside the envelope; nothing sent past the node's ciphertext bound.
A stored message is read signature first, then key, then content, and one
that fails is shown as unreadable, never dropped. Not done here: the Tier 2
roster check on the signing device.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/packages/meshbay-cli/src/meshbay_cli/manpage.py b/packages/meshbay-cli/src/meshbay_cli/manpage.py
index 3fa9550..4491896 100644
--- a/packages/meshbay-cli/src/meshbay_cli/manpage.py
+++ b/packages/meshbay-cli/src/meshbay_cli/manpage.py
@@ -45,7 +45,8 @@ DESCRIPTION = r"""
 .B meshbay-cli
 is a member's view of their MeshBay groups from a terminal: sign in, join and
 leave groups, list them and their folders, search them all at once, download,
-upload and delete files, and approve this account's other devices.
+upload and delete files, read and post in a group's chat, and approve this
+account's other devices.
 It talks to the hub only to sign in and to find a group's nodes; files go
 directly between this machine and the node, end-to-end encrypted, never
 through the hub.
@@ -227,6 +228,13 @@ as it is when the owner hosts it with the desktop application.
 A run that names a file this account may not delete, or a folder, is refused
 before anything is asked or sent.
 .PP
+.B chat
+shows the last messages of a group, oldest first, each with its time and the name
+its sender sealed in it, and posts one with
+.BR \-m .
+Messages are encrypted and signed end to end, as the application's are; one this
+machine cannot verify or open is shown as unreadable, never left out.
+.PP
 .B browser\-access on
 makes this machine leave, on each node it opens a group on, a copy of its keys
 sealed under your passphrase, so that a browser can open the group;
@@ -301,6 +309,8 @@ meshbay\-cli ls \-\-json \-R / | jq '.[] | .path'
 meshbay\-cli search \-t audio holiday
 meshbay\-cli search beach 2024 | head \-1 | xargs \-d '\\n' meshbay\-cli get
 meshbay\-cli rm 'Family/documents/draft*.odt'
+meshbay\-cli chat \-100 Family
+echo 'On my way' | meshbay\-cli chat Family \-m \-
 meshbay\-cli devices approve Family@bob ZX4P\-7QRT
 meshbay\-cli leave \-\-yes Club@carol
 .EE
@@ -400,7 +410,7 @@ def render() -> str:
     out += [".SH REMOTE PATHS", PATHS.strip(),
             ".SH INTERACTIVE MODE", INTERACTIVE.strip(),
             ".SH SESSION, DEVICES AND NODE KEYS", SESSION.strip(),
-            ".SH GROUPS: JOINING, LEAVING, DELETING, DEVICES", MEMBERSHIP.strip(),
+            ".SH GROUPS: JOINING, LEAVING, DELETING, CHAT, DEVICES", MEMBERSHIP.strip(),
             ".SH EXIT STATUS"]
     for code, text in sorted(EXIT_CODES.items()):
         out += [".TP", f".B {code}", text]