Files
hexis/internal/nexusclient
kami 47be24c4cc Validate execution targets against Nexus instead of accepting free text
Finding 3 of REVIEW-2026-07-30.md. target_entity_id was accepted as any
non-empty string; the engine only compared it against a pinned TargetEntityID,
which is empty for every registered capability. Spec §4.3: "Hexis never
accepts a free-text target. Ever."

Targets are now checked in order: ent_ shape (free, never touches the
network), pinned target, existence in Nexus, entity still active, and a match
against the capability's TargetTypes. Validation runs before a confirmation is
consumed, so a bad target cannot burn one, and at confirmation-mint time too,
since a confirmation binds a target.

Two deliberate calls:

Nexus unreachable fails closed (503, ErrTargetUnverifiable). Failing open
would reinstate exactly this hole the moment Nexus blips, and hand it to
anyone able to degrade Nexus. Hexis holds no entity table, so "unreachable"
and "I cannot tell if this target is real" are the same statement. The cost is
that executes now require Nexus liveness; the lookup is bounded at 5s so a
hung Nexus fails fast rather than consuming the capability timeout.

An empty TargetTypes means no type constraint, not a bypass — the entity must
still exist, be canonical and be active. Rejecting empty outright would
disable 16 of the 19 registered capabilities, since only the docker.* entries
declare a target type.

The spec's stronger blessing guard is not implementable: Nexus has no blessing
concept at all. This is the achievable guard, and strictly weaker.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Uea55zaiWuEByEDC4UBSdd
2026-07-30 23:39:40 +04:00
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