What probably matters to youSection of the release
Two new hook/event kinds, prompt.context and session.start, are now recognized for host-plugin messaging validation and payload-shape mapping. session.start is wired up: the terminal REPL calls a new _raiseSessionStart() unconditionally during session start, sending {loaded, surface: "terminal", interactive: true}, with a corresponding event schema payload of {cwd}. prompt.context appears in the same validation and telemetry site tables alongside other prompt-family events, but no direct emitter was found in this slice. Both event kinds were also added to the telemetry site registry alongside existing tool/prompt/agent/turn sites.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed sinceAnthropic's documentation has since written up session.start, on Use the mods API.Work that outlives one event, such as checking on something once a minute, runs on a timer you start from `session.start`. A hook itself runs for one event and has a [time limit](/docs/en/plugins/mods/reference#limits) on its own execution…plugins/mods/apisee the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up session.start, on Use the mods API.
