No user-facing features, improvements, or bug fixes were identified in this release. The structural similarity between v2.1.86 and v2.1.87 is 99.9%, with only 13 additions, 13 removals, and minor structural adjustments.
The sole meaningful code change is an internal refactoring of the BriefTool registration: it was previously conditionally included in the tool list via a lazy-loaded variable (...(BHK ? [BHK] : [])), and is now included directly as a module-level reference (os1). The tool's isEnabled() gate remains unchanged, so this has no effect on behavior. The BriefTool itself (renamed internally to "SendUserMessage") continues to function identically — its entitlement check (isBriefEntitled), enablement check (isBriefEnabled), schema, and implementation are all unchanged.
BriefTool direct inclusion (search for BriefTool: () => os1 in new version vs BriefTool: () => h8z in old version; registration change visible at the KK6() tool list function)