Status: Accepted

Channel sidebar is the scoped right sidebar of Bot mode

Bot mode’s layout names three regions. The App Sidebar is the DSH-native left column; in Bot mode it renders the Roster. The Channel body is the center: the selected Channel’s header, primary content, and composer. The Channel sidebar is the right region, and its scope follows the current selection — a group Channel scope shows that Channel’s membership and management information, and a PersonaBot DM scope shows that PersonaBot’s own sections such as Assignments (事项), Memory, Bot Inbox, and Computer. Chat is always the Channel body and is never a Channel sidebar entry.

Every entry in the Channel sidebar is a Channel sidebar entry: a registered descriptor with a stable id, label, order, scope filter (channel or personabot), and a renderer that may display information, offer controls, or both. Entries register through one BotHarness client service with slot-like semantics borrowed from DSH’s UI slots — ordered, additive, removable — so an independently installed plugin bundle can contribute an entry without the shell importing any destination code. BotHarness registers the built-in entries itself (members for a group Channel, Assignments for a DM). An unregistered, unauthorized, or empty entry is absent; the sidebar never renders placeholders.

Entries collapse independently rather than as an accordion, start collapsed, and remember their expanded state per Channel and PersonaBot in client-local storage — the same class of presentation preference as the left roster’s Channel section collapse. The Channel sidebar as a whole is always visible on wide layouts and can be collapsed with the same remembered preference; on narrow layouts it is hidden by default and revealed as an overlay from a control in the Channel header. It never becomes an icon rail: rail behavior belongs to the collapsed App Sidebar. Exact widths, breakpoints, and transition geometry are settled in the dsh-ui measure-the-shell workflow, not here.

This region is BotHarness’s own, rendered inside the Bot mode panel. It is not DSH’s session-scoped native right column (rightbar / sidebar.right.* tabs), and it must not claim that slot: a Channel sidebar’s scope follows a Channel or PersonaBot, which outlives and is not identified by any single DSH Session.

Considered Options

• Reusing DSH’s native right column (sidebar.right.pane.tab) — rejected: it is session-scoped and tab-shaped, while the Channel sidebar is scoped to a Channel or PersonaBot and reads as one stack of collapsible entries; the native column also has no DM semantics in the pinned DSH.
• Shadowing the native rightbar slot outright — rejected: it would replace the native right sidebar for DSH sessions and is not documented as a supported extension.
• A floating overlay as the permanent home (shell.overlay) — rejected: overlays host transient surfaces; entries need persistent, ordered, collapsible placement. The Computer tracer’s overlay is an explicit temporary host.
• Keeping PersonaBot navigation as the area name and showing nothing on group Channels — rejected: the right region is scoped by the selected Channel too, and a group Channel needs membership and management information.
• A per-destination panel built by each plugin — rejected: it would produce several competing right-side surfaces; one shell owns geometry, collapse, and ordering.
• Accordion entries — rejected: a Human may want two entries visible at once (for example members and Assignments), and shared accordion state survives scope switching poorly.
• A rail or icon column on narrow layouts — rejected: rail semantics belong to the collapsed App Sidebar; the Channel sidebar hides behind an overlay control instead.

Consequences

• PersonaBot navigation retires as an area name. Its meaning splits into Channel sidebar (region) and Channel sidebar entry (one collapsible registered item); DM scopes naturally carry PersonaBot-specific entries without a second area name.
• ADR-0029’s “a group Channel has no PersonaBot navigation” stays true for PersonaBot entries but no longer describes the whole right region: a group Channel has a Channel sidebar with scope-appropriate entries.
• The registration seam is a client-side Cordis service, not a new DSH slot kind; cross-bundle contributions rely on provide/inject because value imports across client bundles are a build error.
• Registrars supply the default order. Human order and item visibility are browser-local presentation preferences, shared within DM and group scopes separately; one edit draft saves both with Done, discards both with Cancel, and can restore all available entries in registrar order (#721, #809). Hidden entries remain recoverable through settings and retain permission listeners; their bodies do not mount, and hiding never changes Host access or execution.
• Whether any entry may take over the Channel body is deferred; until then every entry renders inside the Channel sidebar, which supersedes ADR-0029’s “Memory replaces the center body” wording. (Answered by ADR-0085: no Channel sidebar entry takes over the Channel body; a PersonaBot Profile view may occupy it as a mode rather than an entry.)
• Expanded/collapsed state lives in client-local presentation storage per Channel/PersonaBot and never enters Host authority or a Soul.
• The first tracer delivers the shell with two real entries (group members; DM Assignments) and stops for Human verification. Computer migrates from its overlay into an entry later; Bot Inbox and Memory follow their own authorities.