Session.append accepts event data from arbitrary plugins/tools, so a caller
can pass a SHALLOW-frozen object with mutable descendants. The old
Object.isFrozen early-return skipped such an object entirely, leaving its
descendants mutable in the log — exactly the history mutation ADR 0012 means
to catch. Now always descend, tracking visited objects in a WeakSet for
cycle-termination and idempotence. Addresses PR review finding.
- HMR state soundness: inject sessions, rebuild per-session trace by replaying
each existing session's log at (re-)apply, so a reload mid-turn no longer
falsely rejects the next event
- tighten nesting: turn/end rejects an open step; step/start rejects an open
step; chunk/message/tool events must name the open turn+step; pendingCalls
clears at step/end so a cross-step tool/result can't satisfy a stale call
- drop the default export (it stripped the inject metadata when loaded by
name; functional plugins expose named exports only — matches tool-bash)
- document deepFreeze's top-down precondition; sync RFC 005/008 bodies to the
as-implemented decision
New @deepseek-ai/dsh-invariants plugin (pure listeners, off in prod) asserts
the event taxonomy at runtime — seq monotonicity, turn/step nesting, a
tool/result needs a prior tool/call (NOT the converse), legal agent/status
transitions — and deep-freezes logged event data so mutating history throws.
Seeded sessions are checked + frozen on session/created.
The real RFC 008 fix is always-on: deriveMessages now structured-clones the
content it emits, so the loop's sanctioned request/adapter mutation can no
longer reach back and rewrite the append-only log. The pervasive
DeepReadonly<T> type flip is rejected (compile-only, high-noise, castable) —
recorded in ADR 0012, which folds in RFC 008. Wired into both demos.
