Grounded in the alknet-docker POC (seed codec) and the alknet-tty POC
(2026-07-05, validated the control channel, the local-PTY blocking→async
bridge, and the signal-delivery contract).
Four ADRs:
- ADR-052: wire format — alknet/tty ALPN, two-carriage (JSON negotiation
then raw chunks), fixed channel set 0-3, control as JSON, negotiation-
error framing disambiguation
- ADR-053: TtyBackend trait + TtyHandle — the backend inversion point;
exit_code as a Future; REQ-TTY-01 (backends need not be natively async)
- ADR-054: local backend as alknet-tty-local sibling crate behind a
feature re-export; PTY vs pipe per-session; runner pattern preserved
- ADR-055: exit code on a stream_type 3 control chunk; "exit chunk is
last" invariant; adapter owns the ordering
Five component specs (crates/tty/): README, overview, tty-wire, tty-
backend, tty-adapter, tty-local. The docker/SSH backends are future
crates (out of scope); the trait shape is committed so they can be
built against it.
Five OQs (OQ-43…47): two resolved (TtyControl Clone, stdin closure),
two deferred(scope) (terminal modes, runner API surface), one open
low-risk (flow control).
Zero critical issues from a general-subagent architecture review;
warnings addressed (inline rationale trimmed to ADR refs, TtyError and
StdinCmd defined, framing disambiguation documented, missing ADRs added
to index tables).
