- the subagent projection's empty state becomes a serializable null
sentinel (undefined fields vanish in JSON push frames, leaving stale
identities in clients); consumers treat null and a missing key alike,
and cached sentinels defer to the authoritative refold
- the tool catalog generator mounts the projection registry for
list_agents; the shared unavailable-error copy goes catalog-neutral
- the design note's verification section records the new
subagent-diagnostic snapshot honestly, the 2026-07-22 note's test
inventory is rewritten to the current mechanism, and the session-store
error code is documented
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