Addresses a fifth review pass against 14136e5b. All six findings reproduced
locally before fixing.
1. High — generic peer replacement removed scope memberships.
`set_peers_for_session` soft-deleted every active SessionPeer row, and the
request-level guard only inspected names *present* in the replacement map. A
caller detached a scope by simply omitting it, never naming it — so no
request-level guard could ever see it. Reproduced: scope sessions went
['<id>'] -> [] on a 200. The exclusion now lives in the UPDATE itself
(correlated NOT EXISTS against scope_peer_clause), so replacement means
"replace ordinary peers" regardless of request contents or concurrent creation.
2. High — peer cards could be pre-seeded for future scopes.
`set_peer_card` resolves only the observer and writes a JSONB key derived from
an unchecked observed name, and the route guard rejected only *existing*
flagged scopes. Reproduced: PUT card with target=scope.<missing> returned 200,
creating that scope then returned 201, and the card described the real scope.
3. High — dreams could be queued for future scopes.
The route checked `observed` in a read-only session that closed before
`enqueue_dream`, and a missing reserved name passes any is-it-a-scope check.
Reproduced: 204 with observed=scope.<missing>.
2 and 3 share a root cause, so they share a fix: a new `reject_scope_observed`
that is stricter than `reject_scope_peers` in exactly one case — a *missing*
reserved name is refused, because nothing on these paths creates the peer, so
nothing else would ever catch it. Existing unflagged squatters still pass.
Both guards moved to the mutation point: card validation into
`crud.set_peer_card` (same transaction as the JSONB write, so Dreamer and
agent-tool callers are covered), dream validation into `enqueue_dream` (same
transaction as the queue insert). The redundant route-level checks are dropped
rather than left as weaker duplicates.
4. Medium — prefixed NUL names still reached PostgreSQL.
`reject_scope_peers` filtered for the reserved prefix and sent matches to a
text comparison, so "scope.future\0name" raised psycopg.DataError — a 500.
Both guards now share `_reserved_name_candidates`, which materializes the input
once and rejects impossible values before any SQL. Materializing matters
independently: the message-author path passes a generator, and validation
iterates separately from the prefix filter, so a generator would be
half-consumed. `_reject_impossible_peer_names` now takes a Collection so the
type checker enforces that.
5. Medium — representation kept a check-to-use race.
The previous commit claimed both representation roles were rechecked after
resolution; that was wrong — only the dialectic preflight got that check, and
the representation route never goes through it. It now opens one short
read-only session *after* the embedding call, checks both positions, and passes
that same session to `get_working_representation`, so no connection is held
across external work and a scope committed later cannot have conclusions in the
collection being read.
6. Low — policy coverage was not exhaustive. `sender_id` reaches CRUD as
`observed` but was missing from the detected parameter set. ALLOW cases could
also not carry builders, so the suite never proved the other half of the
contract — that legitimate scope *observers* keep working, which a guard
rejecting scopes everywhere would satisfy. Both fixed; observer positions on
conclusions, dreams, cards, session context and queue status are now asserted
behaviorally.
Deliberately not implemented: the scope-creation backstop scanning for
pre-existing card keys and queue items naming a future backing peer. Reasoning is
recorded in `get_or_create_scopes` — no new such state can be created now, any
pre-existing row is coincidental since `scope.` was never a meaningful namespace,
the consequence is inert, and detecting card keys means a full table scan per
scope creation.
Mutation-tested each new guard: removing the replacement exclusion fails both
membership-preservation tests; weakening either observed guard to existing-only
fails the pre-seeding tests.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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