Owner direction 2026-09-07 (same instruction as the sibling unknown-
command fix, previous commit): plugin-originated text must land in
the chat window instead of retail's ClientLocal (0x1A) SpewBox-only
channel. AppAutomationSurface.PostSystemMessage -- the production
implementation of IPluginChat.PostSystemMessage that MossTank/VTank-
style plugins call -- now passes RetailLogTextType.Default instead of
ClientLocal to RuntimeCommunicationState.AddText, so the text reaches
the chat transcript via Chat.OnSystemMessage instead of the SpewBox.
This matches Decal's own AddChatText behavior for plugin output.
IPluginChat.PostSystemMessage's doc comment is updated to describe
the new destination instead of the old one. Register row AD-124
(previous commit) already covers this site alongside the sibling
unknown-command change.
Mutation check: temporarily reverted PostSystemMessage's AddText call
back to ClientLocal and confirmed the new
AppAutomationSurfaceTests.PostSystemMessage_RoutesToChatLog_NeverSpewBox
test fails (Assert.Single() on an empty chat log) before restoring the
fix. Also adds ChatVMTests.RecentLines_ShowsPluginSystemMessage_TaggedDefault
pinning that a ChatVM bound to the same ChatLog surfaces the line.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2b65217d29