Design review from the alktunnels Phase 0 research pass, verified
against tree a22b2b8 (0.4.1). Findings numbered E-01..E-04:
- E-01 [major] — the open op cannot fail after allocation: the
wrapper replies {channel_id} the moment the OpenHandler is spawned;
establishment failures (params-valid-but-rejected, backend lookup
failure, target dial failure) present to the consumer as a
successful open followed by an instant, indistinguishable clean
EOF (implicit-EOF mux path + unified poll_read EOF arms). SSH
semantics (RFC 4254 §5.1 open-failure reply with reason codes;
channel never exists opener-side), SOCKS5 reply codes, and
udpgw's opaque ERR bit (counterexample) surveyed in
alktunnels/docs/research/ssh-socks5-survey.md. alktty's in-band
error-frame mechanism (send_negotiation_error, 0x00-peek) is the
per-crate workaround this upstream establisher obsoletes for the
channels path. Proposed shape: an awaited establishment hook
(OpenEstablisher) or await-and-inspect OpenHandler, tearing down on
failure and replying channel:open_failed with SSH-four reason codes
in ADR-016 details. Remediation sketch + verification gates
included.
- E-02 [minor] — services/list discloses no per-op metadata; OQ-40
(channel/resources/subscribe) becomes load-bearing for the first
time via the alktunnels discovery resolution (OQ-TN-08).
- E-03 [minor] — OpenHandler-exit vs channel/close teardown race is
benign (ledger take is the gate) but the let _ = discard at
operations.rs:509 is silent; recommend log-or-comment.
- E-04 [minor] — early-arrival park cap (64) is an observable bound
for push-first producers under slow adopters; no change requested,
filed so the constraint is visible to the next consumer.
Non-findings recorded: open-op ACL path complete across all three
dispatch entry points; input_schema enforcement covers open params;
EOF arms unified; channel_open marker + resource_id_path wire
round-trip intact; opener-ledger decrement atomic at every call site.
alkcall tests: 597 passed (docs-only change; baseline check).
glm-5.3-flash
88e3f5e9c3