Every session event now lives inside a turn (between turn/start and its
turn/end). The loop records queued user/message events AFTER turn/start;
an idle agent.inject() wraps its context/message in a one-shot injection
turn. This makes the turn the single durability/replay boundary so a
persistence backend can treat anything after the last turn/end as a
crash tail without dropping legitimate between-turn context.
A failure once the turn is already closed (rejecting session/flush, a
throwing agent/turn-end listener) has no in-turn position for a session
error event, so it is reported via agent/error + logger only; the turn
stays balanced. failTurn appends an error event only while the turn is
open.
The dsh-invariants plugin enforces turn-enclosure via a default case:
every non-boundary event type — including plugin-added merge-extensible
keys — must sit inside an open turn or it throws.
Documented in ADR 0017 + architecture.md.
Adds the durable-session metadata seam and enforces the log's
JSON-serializability invariant at the source:
- SessionHeader / SessionSummary / SessionMeta and CreateSessionOptions in
dsh-session; Session gains a readonly `header`; SessionStore.create takes
`(id?, options?: { seed?; meta? })` (validated absolute cwd, parentSession
lineage). The injection TurnTrigger variant is added for the idle-inject
one-shot turn that a later change introduces.
- isJsonValue (new json.ts): a value round-trips through JSON losslessly —
rejects BigInt, function, symbol, undefined, non-finite numbers, sparse
arrays, circular refs, and exotic objects (Map/Set/Date/class instances).
- Session.append throws on non-JSON-serializable data, and the Session
constructor validates every seed event (isJsonValue + contiguous seq from
0), so a replay/fork seed can never build a live log no backend can
persist — the source-level guarantee a durable backend relies on.
Migrates the ~3 internal positional-seed `create(id, seed)` call sites to
`{ seed }`, and adapts the invariants tests forced by the new guard (the
bad-seq seed is now caught by the constructor; the cyclic deep-freeze test
drives via session/event since append rejects cyclic data; a direct
session/event drives the invariants seq-monotonicity check). Docs kept
backend-agnostic (the persistence packages arrive in a later PR).
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.
