The parent implementation introduced sandboxMode and approvalPolicy as generic SessionHeader fields, then propagated those fields through both persistence backends, session-query indexes, collision checks, policy-specific seed-boundary folds, catalogs, and a broad test matrix. That storage plane is unnecessary: Session already accepts a validated constructor seed, and persistence captures that seed when the session is announced before committing its first batch.
Capture each parent override synchronously at delegation, append source-tagged sandbox/mode and approval/policy records after the optional fork prefix, and create the child with that combined seed. Keeping header.seedLength at the original fork-prefix length preserves lineage while ordinary last-event-wins folds make the inherited records outrank stale parent history and remain subordinate to later child switches. Unswitched parents still stamp nothing, so children continue to follow deployment defaults.
Remove the generic header fields and every persistence/query/schema branch built around them. Collapse the inheritance suite from ten leaking scenarios to four owned-context cases covering real filesystem confinement, stale fork precedence, delegation-time capture, and the no-override path. The assembled headless snapshot now asserts the persisted inheritance event directly.
This keeps the security behavior while restoring policy ownership to the existing event log and deleting the speculative durability machinery that the original tests did not exercise.
Review fix (ds-review-bot on #623): the READMEs and JSDoc still stated the
pre-baseline formulas — resolve() outranking 'the session's last
sandbox/mode event', 'effective = explicit grant ?? fold(events) ??
deployment default', and the approval README's 'last approval/policy event'
opener — which contradict the shipped semantics for a delegated fork whose
seed tail differs from its header baseline. Every statement now names the
override chain (own post-seed switches ?? inherited header baseline): both
READMEs (both languages), resolve()'s JSDoc, the session-mode module and
event-declaration docs, the raw folds re-scoped as building blocks, and
the regenerated catalogs.
Review fixes (ds-review-bot on #623):
- overrideOf (both knobs) rejects a seedLength past the log end before
slicing: a malformed durable boundary would otherwise empty the
own-switch slice until the log outgrew it, letting a wide baseline
shadow a REAL later tightening. Malformed durable metadata fails loud,
never open.
- The session-query derived index carries the two baseline fields end to
end: schema columns on both session tables (SESSION_QUERY_SQLITE_SCHEMA
_VERSION 6 — derived, rebuilds in place), inserts, header selects, the
candidates CTE, rowHeader, sameHeader, and the cross-source
assertSessionHeadersCompatible — so a search hit's header keeps the
child's inherited confinement and conflicting live/persisted baselines
reject.
Red-first: out-of-range seedLength tests in both policy suites;
baseline round-trip and live/persisted baseline-conflict tests in the
session-query sqlite suite.
Review fix (ds-review-bot on #623): the unconditional slice regressed the
public SessionStore.fork path — a generic fork child gets seedLength but no
policy baseline, so slicing discarded its seed-carried sandbox/approval
switches and silently widened it to the deployment defaults (a forked
read-only/never parent produced a workspace-write/ask child).
overrideOf now branches on baseline presence: with a header baseline (a
delegation child) the fold covers only own post-seed switches — the
baseline captured from the parent's FULL log subsumes seed history; without
one, the whole log — seeded switches ARE the replayed inherited truth. The
permission preset fold scopes the same way. Red-first: generic-fork
seed-carried override tests in both policy suites.
Review fixes (ds-review-bot warnings on #623):
- One chain, every consumer: the override resolution (own post-seed
switches ?? header baseline, closed-vocabulary validated) moves into pure
exports (sandboxOverrideOf / approvalOverrideOf); the services delegate,
and the permission presets consume them — current(session) and set()
now see inherited baselines, so a child inheriting danger-full-access
gets REAL knob switches when workspace-write is selected instead of a
silent no-op, and a seed-carried preset selection is subsumed by the
baseline. current(events) becomes current(session) (pre-release; the
only callers were tests).
- Unconditional durable validation: a malformed header baseline fails
loud on every read, no longer shadowed by an own switch.
- The two policy peers are declared optional (peerDependenciesMeta), so a
thin spawn/fork deployment without policy plugins can consume the
driver; verify-runtime-closure honors the flag.
Red-first: inherited-preset derive/switch-away and seeded-selection tests
in the permission suite; malformed-baseline-with-own-switch tests in both
policy suites.
Extend SandboxMode enforcement from bash to the filesystem tools, the sandbox
RFC's deferred cross-family phase.
- dsh-sandbox-policy (new, ctx.sandboxPolicy): the single home for the
deployment default mode + workspaceRoot and the per-session override event,
renamed bash/sandbox-mode -> sandbox/mode and moved here with its fold/setter.
Decouples the bash seam from dsh-session.
- dsh-fs-sandbox (new): SandboxedFileSystem extends LocalFileSystem and fences
write/edit by the per-call mode (read-only denies, workspace-write contains to
the workspace + temp roots via the shared writableRoots, danger passes
through); reads pass through. Structured FS_SANDBOX_DENIED; in-lock parent
re-canonicalization. A policy fence in trusted code, not a kernel boundary.
- dsh-sandbox: the shared escalation kit (writableRoots, the strictly-wider
ladder, denial/hint markers, approveEscalation) both tool families use;
approveEscalation takes a structural approver so dsh-sandbox gains no
approval/agent dependency, and both tools stay duplication-free.
- tool-fs: write/edit advertise sandbox_permissions/justification under a
confining ctx.fs, map FS_SANDBOX_DENIED to the shared [sandbox: ...] marker,
and resolve the same one-approved-wider retry.
- examples/acp-agent: composes sandbox-policy + fs-sandbox, drops the gating
that disabled the fs stack under confined modes.
RFC docs/rfc/implemented/feature/2026-07-14-cross-family-fs-sandbox.md; the old
sandbox RFC's In-process/deferred/FAQ sections updated to shipped fact.
