What it is
A new session.compact plugin hook can intercept and rewrite conversation compaction
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.267.
Presence across releases
0The miner has never read a build containing this name. It is here because a changelog entry of ours names it, which is evidence that it existed and not evidence of which releases carried it. The inventory starts at v2.1.138 and everything older than that was never mined.
First cited
5The earliest release whose published evidence quoted session.receive was v2.1.267, 9 Sep 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table above.
Names beside it
Every settings key in the inventory starting session, up to twelve of them.
sessionA per-session workshop document gets snapshotted with your session files and is only writable in plan mode. never mined
session.attachPlugin hooks can now react to tool-call dry-runs, config changes, and session attach/detach events. never mined
session.authorizePlugins gain $.session.authorize(), which mints an auth handle for the session. never mined
session.compactA new session.compact plugin hook can intercept and rewrite conversation compaction never mined
session.detachPlugin hooks can now react to tool-call dry-runs, config changes, and session attach/detach events. never mined
session.endTwo new lifecycle events, session.end and session.measure, added for plugins and hooks never mined
session.measureTwo new lifecycle events, session.end and session.measure, added for plugins and hooks never mined
session.rootPlugin API policy list adds session.root, prompt.read, and ui.panes as permitted actions never mined
session.startTwo hook events arrive: session.start fires on terminal session start, and prompt.context is registered but has no emitter here. never mined
session.surfacesA new plugin hook event, session.surfaces (plural), joins the existing session.surface never mined
session.turnCountPlugin API hook session.turnCount renamed to session.turns never mined
session.turnsPlugin API hook session.turnCount renamed to session.turns never mined
Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the settings key does. All settings keys.