What probably matters to youSection of the release
What
PostToolUse hook responses accept a new optional classifierContext string, carried alongside the tool result to the classifier that decides permissions in auto mode. It is capped at 2000 UTF-16 code units shared across all hooks for a single tool call, honored only on synchronous hook responses, and dropped if the paired output rewrite is rejected or superseded. Anyone writing a hook on this build can use it.
Details
Added to both the SDK-facing hook schema and the internal one, so it is documented to hook authors as well as accepted at runtime.
The description states that relaying a genuine user statement may satisfy a consent bar, but never a hard boundary.
No feature flag on the schema itself.
Evidence
Host-asserted context shown to the auto-mode permission classifier alongside this tool call's result.
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
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 classifierContext, on Choose a permission mode.You can annotate a call's result with a [PostToolUse hook's `classifierContext` field](/docs/en/hooks#annotate-a-result-for-the-auto-mode-classifier), which the classifier reads as application-provided context. The field requires Claude Co…permission-modessee 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 classifierContext, on Choose a permission mode.
