# Changelog

All notable changes to this crate are documented here. The format is
based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and
this crate adheres to [Semantic Versioning](https://semver.org/).

## [0.8.1] - 2026-09-28

Bug-fix release: a duplicate `adopt_channel`/`open_channel` no longer
destroys the live channel it collided with, found by the crate's new
fuzzing harness (`fuzz/` workspace — five cargo-fuzz targets, committed
seed corpora, three 10-minute campaigns clean). No API or wire-format
change; the error is still `Err(ChannelExists)` — the difference is
entirely in what the collision leaves behind.

### Fixed

- **Duplicate adopt/open no longer replaces the live channel's state
  (found by the `manager_routing` fuzz target,
  `docs/research/fuzzing.md` §7.8).** `ChannelManager::open_channel`
  and `adopt_channel` used `HashMap::insert(...).is_some()` as the
  collision check — but `insert` *replaces* an occupied entry and
  returns the old value, so a duplicate on an in-use id installed the
  new `ChannelState`, dropped the live channel's `demux_sender`
  (spurious EOF to its readers; all subsequently routed chunks lost),
  and *still* returned `Err(ChannelExists)`. The mux write half kept
  framing onto the transport for a channel the demux no longer fed.
  Both functions now check `contains_key` and return before any map
  mutation — the live channel's routing state is untouched on
  collision. Reachable whenever an open-op response is replayed or a
  connection-owner race re-announces an id. Regression tests:
  `adopt_channel_duplicate_id_leaves_live_channel_intact`,
  `open_channel_duplicate_id_leaves_live_channel_intact` (both verify
  routing survives a rejected duplicate; the first also verifies the
  EOF sentinel remains the only EOF source).

### Added (development)

- **Fuzzing harness (`fuzz/` workspace, `docs/research/fuzzing.md`).**
  Five cargo-fuzz targets over the two attacker-reachable wire formats
  and the stateful channel-routing surface: `chunk_header` (8-byte
  header no-panic/round-trip/accounting), `envelope_frame` (frame
  decode error-shape partition + allocation bound), `manager_routing`
  (`Arbitrary` op sequences over `ChannelManager` with exact counter
  models and the parked-bytes bound), `envelope_semantic` (all six
  event kinds: constructors → serde → framing round-trip), and
  `spec_parse` (attacker-shaped op-register schemas compile or reject
  cleanly at registration). Invariant logic lives in
  `fuzz/shared/` — a stable-toolchain crate replayed as plain
  `cargo test`, so the committed corpora stay executable without
  nightly. Campaigns (10 min per target, detached runner): ~25M
  executions total, zero crashes/hangs/OOMs. The `manager_routing`
  campaign found the 0.8.1 fix above within minutes — exactly the
  stateful interleaving class example-based tests cannot reach.
  `fuzz/` is excluded from the workspace and from the published
  package.

### Verified

- 684 tests pass; `clippy --all-targets -- -D warnings`, `fmt --check`,
  `cargo doc`, wasm32-unknown-unknown check, `cargo semver-checks`
  (no API changes vs 0.8.0), and `cargo publish --dry-run` clean;
  corpus replay (`cargo test --manifest-path fuzz/shared/Cargo.toml`)
  green.

## [0.8.0] - 2026-09-18

Review 008's remediation lands in full — the graduation upstream asks
(U-1 flavor-form open-op ids in discovery; U-2 the establisher → reply
projection) plus the in-tree channel relay they demanded
(`ChannelRelay`, the hub-leg install template, and the review's gate-2
e2e harness). A post-landing audit of that diff hardened the relay's
adopted-entry teardown and the discovery ALPN guards, corrected two
log/error messages, and review 009's coverage debt is paid in full —
all failure-path; no wire or API changes. The channels data plane is
untouched (ADR-034/035's one-way doors stay closed); the new surfaces
are additive on the call-plane JSON and the registry seams.

### Added

- **`Establishment` reply projection (review 008 U-2, ADR-049
  amendment 3)** — `Establishment::with_reply_field` /
  `with_reply_fields` / `reply_fields()` (an optional map riding the
  typed-opaque plan carrier). The open-op wrapper merges the fields
  into the success output after reserving `channel_id` — an
  establisher supplying the reserved key fails loudly
  (`channel:open_failed`, reason `handler_error`), never shadows.
  Absent fields leave the reply byte-identical to the pre-amendment
  shape.
- **`ChannelClient::open_channel_with_reply` (review 008 U-2)** — the
  full open-op success output (the extra reply fields, e.g. a
  bind-first listener's `bound`) alongside the streams;
  `open_channel` delegates with the fields discarded, its signature
  unchanged.
- **Flavor-form open-op ids in discovery (review 008 U-1, ADR-047
  amendment 3)** — `spec_to_json_pub` emits an explicit
  `channel_open_alpn` string alongside the boolean marker when the op
  name is not a standard `channels/<seg>/(sub|pub)` shape (standard
  shapes stay byte-stable); `rebuild_spec_for` prefers the explicit
  string and generalizes the derivation to strip the LAST path
  segment when the marker is present. `channels/tunnel/direct`-shaped
  ops now reconstruct WITH the `channel_open` marker through
  discovery — hubs relaying through `from_call` never see them as
  plain forwarding stubs.
- **`ChannelRelay` (review 008 Unit 3a, ADR-042 as amended by
  ADR-051)** — the in-tree relay component:
  `ProducerLeg` (`Arc<CallConnection>` + producer-leg
  `ChannelManager` — not a `ChannelClient`, whose `take_call_
  connection` detach is wrong for a hub with multiple connection
  claimants) and `ChannelRelay::register_relay_openable` (registers a
  from_call-imported marked spec on a consumer-leg registry via the
  full open-op wrapper: ACL, per-identity cap/ledger, establishment
  bound, teardown). The translate hop calls the producer leg with the
  forwarded payload (`forwarded_for` from the consumer's per-call
  identity, ADR-026 §3) and adopts the spoke-allocated id; the
  byte-forward hop is `pump_bidi` awaited inline — the hub never
  parses chunk framing, ids are per-connection (no rewrite exists).
  The spoke reply's `channel_id` is stripped (the consumer reply
  carries the hub-allocated id); the reply's other fields ride
  through (`bound` flows end-to-end, per-hop truthful). Reason
  mapping per ADR-051 §3 — the spoke's code and message are preserved
  (`timeout` maps to `dial_failed`, the one non-1:1 row). The
  adopted producer-leg channel entry reclaims when the relayed pump
  completes. Rejection postures are loud: unmarked and Pub-typed
  marked specs fail registration (`RelayError`), never silent stubs.
- **`HubLegImports` + `HubLegTemplate` (review 008 Unit 3b, ADR-051
  §5)** — the hub-leg install template as an in-tree export: the
  `Clone` discover/stash (from_call bundles split by the marker, with
  the per-consumer `filtered`/`only` subset filter) and the
  `install_channel_zero` hook composing fork + generic channel ops +
  bootstrap discovery closed over the fork (review 004 F-06) + plain
  bundles as-is + relay openables + serving-identity resolution
  (CF-005 precedence) + the single-stream dispatch loop. A
  Pub-typed (or unregistrable) marked spec ends the leg's install
  task — channel 0 never dispatches. Discovered bootstrap-discovery
  op names are skipped on re-registration (the template's own
  install supersedes the imported copies).

### Changed

- **New module `src/channels/relay.rs` and `src/channels/hub_leg.rs`
  re-exported from `channels`**; the relay's teardown fix is part of
  this landing (no pre-relay behavior to preserve).

### Fixed

Post-landing audit of the remediation diff — hardening guards,
message corrections, and one rejection-posture fix; all failure-path.

- **Adopted-entry teardown on every relay plan path** (ADR-051 §6) —
  the relay's `RelayPlan` now owns the producer-leg
  `ChannelManager` and reclaims the adopted spoke `channel_id` via a
  `Drop` guard, instead of the pump handler's post-`pump_bidi`
  explicit reclaim. This closes the leak windows the pump's normal
  path cannot reach: the open wrapper's establishment bound expiring
  after the adopt (the plan dropped before the pump ever spawns) and
  the pump handler's early-return arms (plan absent, downcast
  failure, `try_unwrap` failure, `accept_bi` failure). Dropping the
  plan's send half still EOFs the spoke side via the mux pump's
  implicit-EOF sentinel, so the spoke handler reclaims through the
  same cascade as before. Regression test:
  `relay_plan_drop_reclaims_the_adopted_producer_leg_entry`.
- **Empty/whitespace `channel_open_alpn` rejected at rebuild** — an
  explicit string of `""` (or whitespace-only) previously overrode a
  sane name-derived ALPN, poisoning the marker for every consumer
  from one misconfigured producer; `rebuild_spec_for` now trims and
  rejects empties, falling back to the derivation.
- **Empty-segment standard-shape names** — `channels//sub` was
  serialized boolean-only (the standard-shape check saw flavor
  `sub`) but reconstructed UNMARKED (the derivation's empty-segment
  guard returned `None`) — a silent stub for a marked op. The
  standard-shape check now applies the same empty-segment guard, so
  the explicit `channel_open_alpn` string rides the wire and the
  marker reconstructs.
- **Reserved-reply-key error text and log level** — the
  `channel:open_failed` message interpolates `RESERVED_REPLY_KEY`
  instead of hardcoding `"channel_id"` (the two could drift), and the
  establisher-bug log fires at `warn!` (a programming error), not
  `debug!`.

### Testing

Review 009's coverage debt (all seven findings, no wire or API
changes; three as-filed errata recorded in the review):

- **C-1** — the template's plain-bundle install-failure arm is pinned
  (un-compilable `input_schema` → the install task ends before the
  dispatch loop, channel 0 never dispatches); ADR-051 §5 carries the
  loud-install coverage note (relay-openable + plain-bundle arms
  pinned; generic-ops + bootstrap-discovery arms documented as
  best-effort-loud).
- **C-2** — the `HubLegImports` filter: the `filtered` closure path
  and the `only` marked/plain partition unit-tested; the empty-stash
  e2e gate (serves only the generic ops + discovery, dropped ops
  resolve `NOT_FOUND`).
- **C-3** — the batch-form reserved-reply-key rejection
  (`with_reply_fields` smuggling `channel_id`) pinned: reason
  `handler_error`, channel torn down, ledger decremented, pump never
  spawns.
- **C-4** — `open_channel_with_reply`'s failure path pinned e2e: the
  typed error carries the `channel:open_failed` code and the full
  `details` shape (`reason` + `message`) through the new API.
- **C-5** — both "byte-identical" claims are golden-pinned: the
  no-fields reply against the exact `{"channel_id": 2}` literal, and
  the standard-shape wire payload against the full 9-key literal.
- **C-6** — the derivation's edge shapes pinned: `channels//sub` /
  `channels//direct` / `channels` → `None`; the 4-segment strict
  superset (`channels/x/sub/extra` → `Some("x/sub")`) annotated as the
  pre-amendment behavior change; the verbatim `channels/alk/tty/sub`
  case.
- **C-7** — the builder's overwrite semantics pinned last-win (single
  and batch forms) with the doc sentence on `with_reply_field`.

### Verified

- 682 tests pass (`cargo test`), `clippy --all-targets -- -D warnings`
  and `fmt --check` clean. The gate-2 e2e harness
  (`src/channels/gate2_tests.rs`) pins the review's gate 2: the full
  consumer → hub → producer relay through the template (hub-allocated
  id, `bound` surviving, data both directions with a fake 8-byte
  chunk header riding verbatim), hub-side disconnect tearing down
  both legs, the mid-establishment window's two reclaim signals
  (ADR-051 §6), and the `channels/tty/sub` standard-shape companion.

## [0.7.1] - 2026-09-09

The MSRV floor becomes honest: `rust-version` raises from 1.85 to
1.88. The 1.85 claim was already false at the dependency level — the
resolved lockfile pulls icu 2.x (MSRV 1.86) and wasip2 1.87
transitively via `jsonschema` → `idna`, so no 1.85 toolchain could
build 0.7.0. The raise aligns with the ecosystem floor (noq's 1.88,
matching the QUIC path) and breaks no downstream that could build the
crate before. No API or wire-format change; downstreams on caret
requirements pick this up on their next `cargo update`.

### Changed

- **`rust-version` 1.85 → 1.88.** Verified on a real 1.88 toolchain
  (full test suite, clippy). Two clippy lints promoted since 1.85
  were fixed to keep `-D warnings` clean on the new floor:
  `collapsible_else_if` (`channels::mux`) and
  `uninlined_format_args` (`core::types`,
  `registry::registration`). Behavior-identical.

## [0.7.0] - 2026-09-07

The connect-side caller-identity seam (CF-005) plus the full sweep of
every open alkcall finding from downstream consumers (CF-006, CF-007):
a connect-side serving op can now authenticate the
transport-authenticated peer by key-based identity (mTLS/QUIC), the
open-op establisher/pump handler see the per-call opener identity,
and the ADR-016 code list is current. The wire surface is unchanged.

### Added

- **`ServingConfig.identity: Option<Identity>` (CF-005 remediation
  (a))** — an explicit caller identity for the connect-side serving
  dispatch (`ChannelClient::from_connection_with_serving`). Wins over
  the propagated transport identity; the payload `auth_token` path
  still takes precedence over both (ADR-017 §7).
  **Semver-relevant at 0.x:** struct literals must add
  `identity: None`.
- **`core::auth::NoopIdentityProvider`** — a public `IdentityProvider`
  that resolves nothing; the identity-less posture for ACL-free
  serving and the `ServingConfig::default()` provider (three private
  test copies of it existed across the crate).

### Changed

- **The transport identity propagates to channel 0 (CF-005
  remediation (b)).** `from_connection_with_serving` copies the
  transport `Connection::identity()` to the channel-0 connection via
  `set_identity` before the serving loop starts, mirroring the accept
  side (the adapter hands the install hook the transport
  `AuthContext`). The connect-side serving dispatch now resolves the
  caller identity in precedence order: payload `auth_token` →
  `ServingConfig.identity_provider`; `ServingConfig.identity`;
  transport identity. With none, the dispatch runs identity-less and
  `AccessControl::check` fails closed (`FORBIDDEN`) — unchanged. The
  identity resolution is process-local (`set_identity` on the
  internal channel-0 `Connection`); nothing new crosses the transport.
- **The open-op establisher and pump handler see the per-call opener
  identity (CF-006 — the CF-005 corollary).** `run_open_wrapper`
  derives a per-call `AuthContext` — the opener's dispatch-resolved
  identity overlaid onto the install-time context — and passes it to
  both the establisher (ADR-049 §1) and the pump handler
  (`OpenHandler`). Identity-less calls keep the install-time
  identity; transport-truthful fields (`alpn`, `remote_addr`,
  `tls_client_fingerprint`) are never rewritten. Signatures are
  unchanged — behavior-only; on a per-connection registry (ADR-047
  §4) this is identical to before, and on hub-forwarded opens the
  establisher now sees the end client instead of the hub.
- **ADR-016 amended: the protocol-code list is eight codes (CF-007 —
  alkhttp review 006 Part C doc drift).** `ALREADY_EXISTS`
  (non-retryable, `op/register` collision) and `CONNECTION_CLOSED`
  (retryable, provably-undelivered call) are now in the Context
  paragraph, the §3 table, and the `from_openapi` collision rule; §2a
  documents the undelivered-vs-ambiguous write-failure distinction.
  Doc-only.
- **`ChannelPlan` type doc carries the `Send + Sync` payload
  constraint** (alktunnels POC F-1 — a non-`Sync` boxed handle needs
  a wrapper; documented so the next consumer doesn't re-derive it by
  compiler error).
- Regression gates: the four `cf005_*` tests in
  `src/channels/client.rs` (transport propagation, override
  precedence, identity-less failure, token fallback + precedence) and
  the two open-op identity-overlay tests in
  `src/channels/operations.rs`. Ledger: CF-005, CF-006, CF-007 →
  resolved (the ledger's Open section is now empty). Specs: ADR-022
  §connect-side-serving, ADR-016 (code list), ADR-049 establisher
  doc note.

## [0.6.0] - 2026-09-07

The establishment follow-ups sweep (review 007): the `Establishment`
plan payload lands (R-01), the `OpenHandler` lifetime contract is
documented (R-02), and the two-pump helper is extracted (R-03). One
breaking change (below); the wire surface is unchanged.

### Added

- **`pump_bidi` (review 007 R-03 / ADR-050).** The two-pump helper —
  `channels::pump_bidi(channel, peer_read, peer_write)` — pumps a
  channel stream (`BiStream`-shaped) against a peer's split
  read/write halves: one pump per direction, each shutting down the
  opposite sink on completion (alknet ADR-078's shutdown-on-
  completion), joined, returning `(u64, u64)` copy counts. Errors
  are EOF-shaped by design (the POC + ADR-078 semantics — no `Err`
  state; the review sketch's `io::Result` return was dead code).
  The helper pins the contract in one place instead of three
  (alktunnels POC `pump_halves`, alktty's channels session, the next
  consumer). Purely additive.

### Changed

- **`Establishment` carries the channel plan (review 007 R-01 —
  breaking at 0.6.0).** The reserved field is filled:
  `Establishment { plan: Option<ChannelPlan> }` with
  `ChannelPlan = Arc<dyn Any + Send + Sync>` — typed-opaque, because
  the payload an establisher hands the pump handler is a live handle
  (a dialed socket, a TTY handle), not JSON. The wrapper threads
  `establishment.plan` to the `OpenHandler`'s new second parameter
  (`Fn(Value, Option<ChannelPlan>, Connection, AuthContext) ->
  JoinHandle<()>`); `None` when no establisher is registered or it
  returned `Establishment::default()`. Process-local: establisher →
  wrapper → handler; nothing new crosses the transport. This kills
  the side-channel handoff the alktunnels POC shipped (resource-keyed
  slot + poll loop) with its concurrent same-resource race — each
  open's establisher result flows to its own handler. Migration:
  `Ok(Establishment {})` → `Ok(Establishment::default())` (or
  `Establishment::new(handle)` to deliver a handle); handler closures
  gain a `_plan` (or `plan`) parameter.

- **`OpenHandler` lifetime contract documented (review 007 R-02).**
  Doc-only semantics note on the `OpenHandler` type and the
  registration entry points: the returned `JoinHandle` must track the
  data-plane lifetime — the wrapper awaits it and its completion
  triggers channel teardown (drop of the demux sender = EOF to the
  handler's read half); a handler that returns before its pumps
  finish tears the channel down at birth (await pumps inline, never
  spawn-and-forget). Plus a `debug!` telemetry line in
  `run_open_wrapper` when a handler exits without having accepted the
  channel's `BiStream` (the birth-teardown hint).

## [0.5.0] - 2026-09-06

The channel-open establishment phase (ADR-049 — review 006 E-01 +
N-1). Additive establishment machinery; one breaking change (the
`ChannelClient::open_channel` error type, below).

### Added

- **`OperationSpec.description` (review 006 E-02).** Additive
  `Option<String>` op description (builder: `with_description`),
  disclosed by `services/list` and `services/list-peers` (local
  listings) when set, carried in the `services/schema` wire shape
  (`spec_to_json_pub` emit / `rebuild_spec_for` parse — the field
  survives `from_call` discovery and `op/register` announcement).
  Describes the op, not the produced resource set (ADR-047 §6
  amendment: the live resource-enumeration half stays deferred,
  OQ-40). Absent on the wire when unset — additive for all consumers.

- **Channel-open establishment phase (ADR-049 — review 006 E-01).**
  `ChannelCore::register_openable_with_establisher` registers a
  per-ALPN open op with an establisher hook (`OpenEstablisher`): an
  awaited establishment phase — validate params semantically, dial the
  backend — bounded by the dispatch deadline or the registration's
  timeout override, else `ESTABLISHMENT_TIMEOUT` (10s; the earlier of
  the two). On establisher failure (error or deadline) the wrapper
  tears down the just-allocated channel (demux sender, opener-ledger
  take, `policy.on_close` un-increment — the allocation and teardown
  balance) and replies `channel:open_failed` with
  `details: { reason, message }`, reason ∈ `dial_failed` /
  `unknown_resource` / `resource_shortage` / `handler_error` /
  `timeout`. The SSH contract holds consumer-visibly: a failed open
  never returns a `channel_id`. `register_openable` is unchanged
  (no establisher = always-OK, existing registrations compile and
  behave identically); the establisher takes `(input, auth)` — the
  channel's yield-once `BiStream` belongs exclusively to the pump
  handler. Additive wire surface (new error-code string + `details`
  shape).

### Changed

- **`ChannelClient::open_channel` returns a typed error (ADR-049 §4 —
  review 006 N-1, breaking at 0.5.0).** The open op's `CallError` is
  carried verbatim in `ChannelOpenError::CallFailed` instead of being
  flattened into a debug-formatted string, so consumers branch on
  `channel:open_failed`'s typed reason (`establishment_reason()`).
  Other variants: `MissingChannelId` (malformed success reply),
  `AdoptFailed` (local adoption failure). Mechanical for consumers —
  the `String` was a debug-formatting wrapper.

## [0.4.1] - 2026-09-05

Bug-fix release: chunks arriving for a not-yet-adopted channel are
parked instead of dropped (the open-op response / first-data race).
No API changes.

### Fixed

- **Early-arrival chunks for un-adopted channels are parked, not
  dropped.** The connect side adopts a channel (installs local routing
  state) only after the open-op response arrives, but the accept side's
  `OpenHandler` can start pumping data the moment the channel opens —
  the two race. Previously the connect side's demux dropped those
  chunks (REQ-CH-04's lenient unknown-channel drop), silently losing
  the first chunks of any push-first producer (a TTY backend's banner
  or greeting, a sub protocol's initial frame). `route_payload` now
  parks up to 64 payloads per unknown `channel_id` in a bounded
  early-arrival buffer and `adopt_channel` drains them into the new
  receiver in order; chunks beyond the cap drop with the pre-existing
  debug log and `dropped_unknown_chunks` counter (the counter now means
  "early-arrival overflow or genuinely unknown channel", not just the
  latter). `clear_all` drops the parked buffers with the connection.
  Surfaced by alktty's consumer end-to-end test (review #001 L3): the
  session never resolved because the producer's first chunks (the
  stdout sentinel + exit chunk for an immediately-resolving backend)
  arrived before the adopt and were dropped.

## [0.4.0] - 2026-09-05

`input_schema` is now enforced at call time (the advertise-vs-enforce
leg ADR-016 promised: `INVALID_INPUT` is the registry's
schema-mismatch error code). Minor bump — behavioral break for any
caller that was passing schema-violating inputs to ops declaring a
non-trivial `input_schema` and relying on the validation being
documentation-only.

### Changed

- **`OperationSpec.input_schema` is enforced by the registry on every
  dispatch.** Until now the schema was advertise-only: `services/schema`
  disclosed it, the wire and gateway paths disclosed it, but no dispatch
  entry point consulted it (the only schema alkcall actually enforced
  was `publish_schema` per-chunk on Pub ops, P-03). The schema now
  compiles once at registration (same fail-closed rule as
  `publish_schema`/CF-003: an un-compilable schema is a registration
  error, never a silently-skipped contract) and is checked after the
  ACL gate in all three dispatch entry points — `invoke`,
  `invoke_streaming`, and `invoke_sink` (via `resolve_sink_handler`,
  preserving the P-08 single-source-of-truth property). Violations
  return `CallError::invalid_input("input failed input_schema
  validation")` with the input echoed in `details`. Raw-JSON-Schema
  semantics (permissive on unknown keys) — adapters that want
  closed-by-default enforcement keep doing their own hardening, as
  alkhttp's `CompiledInputSchema` already does; the two checks compose.
  Built-in ops are unaffected: alkcall's own specs declare the empty
  object schema (accepts anything) and `services/schema` already
  returned `INVALID_INPUT` for a missing `name` before its handler ran.
  Motivated by alktty's code review #001 (L1): the channels open-op
  wrapper hands the registry-checked `input` to the `OpenHandler` as
  the authoritative params, which requires the registry to actually
  validate it.
- `OperationRegistry` gained an `input_validator` cache (compiled at
  registration, mirrored on `fork` and in `OperationRegistryBuilder`
  like the publish validators); `input_validator()` is `pub(crate)` —
  the public surface is unchanged.

## [0.3.1] - 2026-09-04

Bug-fix release: `services/list-peers` can now list peer-announced
ops. No API breaks — `OperationEnv` gains one defaulted trait method
(non-breaking for all implementors; `cargo semver-checks` 196 checks
pass against the 0.3.0 baseline).

### Fixed

- **`services/list-peers` shows each peer's operations**
  (UP-03, surfaced by alkhttp's review 006). `PeerCompositeEnv`
  overrode `peer_ids` only, so `peer_operations` fell to the trait
  default (`Vec::new()`) and every peer listed with an empty
  operations array — the ADR-022 amendment's "announced op is
  discoverable via `services/list-peers`" promise never resolved on
  the wire. ADR-030 prescribed the fix but it had never been ported
  into alkcall; the existing `list-peers` unit tests passed because
  they mock `peer_operations` with hand-rolled envs. Implemented per
  ADR-030: `OperationEnv::list_operation_names` (default `Vec::new()`)
  + overrides on `OverlayOperationEnv` (overlay map keys),
  `PeerCompositeEnv` (`peer_operations` delegates to the peer's
  overlay; its own aggregate mirrors `contains()`: session +
  connections + base), `LocalOperationEnv` (registry names), and
  `ChannelsSessionEnv` (delegates to base). Gate:
  `announced_op_is_discoverable_via_services_list_peers` exercises the
  exact `compose_root_env` shape (announce via `op/register`, then
  assert both the `peer_operations` probe and the `services/list-peers`
  wire shape attribute the op to the peer) — verified load-bearing
  (reverting the override fails the gate). ADR-030 status is now
  Accepted with the UP-03 provenance note.

## [0.3.0] - 2026-09-04

The connect side can serve (two-way ops over one channels connection),
per-session fork registries, and the `op/register` bootstrap op — the
remediation of reviews 004 and 005
(`docs/reviews/004-*.md`, `docs/reviews/005-*.md`). Two
`OperationRegistry` methods changed their return types from borrowed to
owned (source-breaking for annotated call sites; minor bump per 0.x
semver rules) — verified with `cargo semver-checks` (196 checks pass
against the published 0.2.0 baseline; the return-type changes were
caught by manual diff review, as the tool has no lint for that
pattern).

### Added

- **`OperationRegistry::fork`** — deep-copies a registry (handlers,
  provenance, composition authority, capabilities, cached
  publish-schema validators) into an independently-mutable copy. The
  per-session shape: fork the deployment's base registry, register the
  session's ops on the fork, dispatch the session over the fork
  (ADR-047 §4 amendment, 2026-09-03). Internally mutable, so a fork
  shared as an `Arc` can receive registrations after the dispatcher
  was built — `install_bootstrap_discovery` relies on this.
- **`OperationRegistryBuilder::from_registry`** — seeds a builder from
  an existing registry's registrations (the fork surface expressed
  through the builder; registration order is not preserved — HashMap
  iteration).
- **Connect-side serving (two-way ops over one connection).** The
  channels connect side's channel-0 read pump previously resolved
  outbound responses only and silently dropped inbound
  `call.requested` frames. New `ChannelClient::from_connection_with_serving`
  takes `Option<ServingConfig>` (`registry` + `identity_provider`);
  with `Some(..)` the read pump becomes the full-duplex serving loop
  (`Dispatcher::serve_single_stream`), so a connected peer can call the
  consumer's ops. `from_connection` keeps the resolution-only pump
  (pure-consumer default). Serving is opt-in: the protocol is
  symmetric, the API is explicit (ADR-022 amendment, 2026-09-03).
- **`Dispatcher::serve_single_stream` and `Dispatcher::dispatch_start`
  + `StartedDispatch`** — the shared serving-loop machinery. Both
  single-stream loops (accept side and connect side) now run the same
  concurrency model: Once invocations, Sub pumps, and sink response
  writers are spawned, so same-connection nested composition resolves
  concurrently instead of deadlocking until the 30 s sweeper (review
  005 G-01). Handles are tracked and aborted at loop exit; no lock is
  held across an await.
- **`registry::op_register` module — the `op/register` bootstrap op**
  (review 004 F-05). A connected peer announces the ops it serves over
  the wire: `OP_REGISTER_NAME` (`op/register`), `OpRegisterRequest`
  (wire round-trip via `to_json`/`from_json`), `op_register_spec` /
  `op_register_handler`. Announcements land in the connection overlay
  and are served through forwarding handlers, so hub→consumer import
  (`from_call`) and consumer→hub announce are symmetric. **Collision
  policy** (review 005 G-03): a peer-announced op may replace other
  peer-announced ops (when `replace` is set) but never the serving
  side's own registrations — a name present on the serving registry
  rejects with the new `CallError::already_exists` (`ALREADY_EXISTS`,
  non-retryable), regardless of `replace`. The collision gate checks
  the serving registry, the session fork, and the connection overlay
  itself.
- **`install_bootstrap_discovery`** (review 004 F-06) — registers
  `services/list`, `services/list-peers`, and `services/schema`
  against a registry with handlers closed over that same `Arc`, so
  per-session forks are the discovery source for their own openables
  (handlers see every op the registry serves at call time). ACL
  filtering stays per-caller. The bootstrap-op set on channel 0 is
  closed and now includes `services/list-peers` (review 005 G-05 —
  doc alignment; the code had installed it since the amendment landed)
  plus `op/register` (ADR-022 amendment).
- **`spec_to_json_pub`** — public serialization of an `OperationSpec`
  into the `services/schema` wire shape (the shape `op/register`
  announces with and `services/schema` serves). **`resource_id_path`
  now survives the spec wire round-trip** (review 005 G-04): both the
  serializer and the `op/register` parser carry the field.
- **`CallConnection::overlay_contains` /
  `CallConnection::overlay_registration`** — read access to the
  connection overlay, for `op/register` replace semantics and
  composition reachability checks.

### Changed

- **`OperationRegistry::registration` returns
  `Option<HandlerRegistration>`** (was `Option<&HandlerRegistration>`)
  and **`list_operations` returns `Vec<OperationSpec>`** (was
  `Vec<&OperationSpec>`). Source-breaking for call sites that annotate
  the borrowed types — clone-at-the-boundary instead. Minor bump per
  0.x semver rules.
- **Registration is `&self` throughout** — `OperationRegistry::register`,
  `ChannelOperations::register_on`, and `ChannelCore::register_openable`
  take `&OperationRegistry` (was `&mut`). Source-compatible for
  callers (reborrow); this is what makes post-construction
  registration on a forked, `Arc`-shared registry possible.
- **`from_call` composition reachability** — the forwarding-handler
  path declares reachable namespaces on the composing handler's
  `scoped_env` (empty is deny-by-default) and the connection overlay
  is attached only for identity-carrying connections (ADR-030 §5).

## [0.2.0] - 2026-08-31

Consumer-findings remediation (CF-001..004 from
`docs/reviews/consumer-findings-ledger.md` — alkhttp as the first real
consumer), the promoted `gateway` dispatch spine (ADR-048), and a
docs-hygiene pass. One behavior change noted below; otherwise additive.

### Added

- **`gateway` feature: the transport-neutral dispatch spine**
  (ADR-048). New `alkcall::gateway` module behind the opt-in `gateway`
  cargo feature (default off; adds no dependencies). `GatewayDispatch`
  is the deadline-bounded, re-rooted-context invoke spine over
  `OperationRegistry` (`invoke` / `invoke_streaming` / `invoke_sink`)
  promoted from alkhttp's gateway after it proved transport-agnostic —
  hubs and spokes relaying calls (ADR-042 translate path) need the
  identical root-context discipline (`internal: false`,
  `forwarded_for: None`) without any HTTP. `schema_disclosure_denial`
  is the shared is-internal + ACL check for `services/schema`
  inner-op-name disclosure (one implementation so transports cannot
  drift; ACL denial returns `FORBIDDEN`, Internal visibility returns
  spec-404 — see ADR-048 for the split from the wire handler's
  conservative spec-404). The handler deadline is a constructor knob
  (`with_deadline`); the default remains 30 s. alkhttp migrates to
  this module in a follow-up and drops its local copy.

### Changed

- **Un-compilable `publish_schema` values are rejected at registration
  time** (CF-003). `OperationRegistry::register` and every
  `OperationRegistryBuilder` method now return `Err` when a Pub op's
  `publish_schema` fails to compile. Previously the bad schema was
  accepted and the dispatch path failed **open** (warn log, chunks
  unvalidated). The compiled validator is now cached per-op
  (`OperationRegistry::publish_validator`) and consumed by the dispatch
  path — the per-request compile is gone. Code that registered
  un-compilable schemas will now get a registration error instead of a
  silently-unvalidated op.

### Fixed

- **`services/schema` no longer discloses Internal or ACL-restricted op
  specs** (CF-004). The schema handler now applies the same gates as
  `invoke()` — Internal-visibility rejection and `AccessControl::check`
  with matching identity resolution. Restricted ops return spec-404
  (`NOT_FOUND`), consistent with "restricted ops don't exist" elsewhere;
  no information leaks about the restricted surface. The gate is inside
  the handler, so every transport is covered.
- **Demux `TooLarge` skip no longer allocates from the peer's header**
  (CF-002). The skip now streams through a fixed 64 KiB buffer, and a
  cumulative 256 MiB skipped-bytes budget tears down connections that
  loop oversized headers. Previously the buffer was sized from the
  untrusted `u32` length (up to ~4 GiB pinned per dribbling peer).
- **Write failures before request delivery are retryable** (CF-001).
  New `CallError::connection_closed` (`CONNECTION_CLOSED`, `retryable:
  true`) is returned when the `call.requested` frame write fails on any
  consumer path (`call`/`subscribe`/`publish`, both stream modes) — the
  call provably never reached the producer, so reconnect/retry is safe.
  Mid-publish write failures and producer-side connection-teardown
  failures remain non-retryable `INTERNAL` (delivery ambiguous). The
  new code string is additive; the `retryable` flag is the
  machine-readable signal for consumers.

### Fixed (continued)

- **Doc hygiene.** Resolved the broken intra-doc link on `lib.rs`'s
  feature-gated `gateway` mention (rustdoc warned on default-feature
  builds), and re-pointed 40 `src/` doc references from the old alknet
  mono-repo ADR numbering (ADR-049/050/052/065/070/074/092) to this
  crate's numbering (ADR-021/011/034/007/008/009/005) so published docs
  reference ADRs this crate actually carries. Failure-path coverage was
  added alongside: the CF-002 skipped-bytes teardown and skip-EOF arms,
  CF-001's subscribe write-failure sites (both stream modes), the
  publish request-frame failure in single-stream mode, and
  non-retryability pinning for mid-publish failures.

## [0.1.1] - 2026-08-17

A minor release that renames the ALPN prefix from `alknet/` to `alk/`
and drops the `alktype` dependency. No public API changes — verified
with `cargo semver-checks` (196 checks pass, no semver update
required).

### Changed

- **ALPN prefix renamed.** All ALPN strings changed from
  `alknet/<name>` to `alk/<name>`: `alknet/call` → `alk/call`,
  `alknet/channels` → `alk/channels`. The rename landed before the
  first published consumer (alktty), so no interop break exists.
  `CHANNELS_ALPN` is now `b"alk/channels"`; `CallAdapter::alpn()`
  returns `b"alk/call"`; `derive_alpn_from_op_name` derives
  `alk/<alpn>` from `channels/<alpn>/(sub|pub)` op names. ADR-004
  amended with the rename rationale. See Review 003.
- **`alktype` dependency dropped.** The only usage
  (`alktype::validation::build_validator`) was a thin wrapper over
  `jsonschema::options().build()`; the call site now uses `jsonschema`
  directly. The crate is leaner — no `alktype` (and no transitive
  `indexmap`/`hashbrown 0.17`) in the dependency tree.
- **`tokio` features slimmed.** `features = ["full"]` replaced with
  `["rt", "sync", "time", "io-util", "macros"]` — the crate uses no
  net/fs/process features. This unblocks `wasm32-unknown-unknown`.
- **WASM support.** The crate now compiles for
  `wasm32-unknown-unknown` (verified with `cargo check` and `cargo
  clippy` on the wasm target). `uuid` gained the `rng-getrandom`
  feature and `getrandom 0.4` the `wasm_js` feature so request-ID
  generation works on wasm.

### Added

- **BAST document for the chunk header.**
  `docs/architecture/chunk-header.bast.json` is the machine-readable
  wire-format spec for the channels 8-byte chunk header
  (`[channel_id: u32 BE][length: u32 BE]`). BAST is plain JSON —
  consumable by any language; the `alktype` crate compiles it into
  readers/writers/validators, and future codegen derives
  language-specific implementations. Embedded in the crate as
  `channels::wire::CHUNK_HEADER_BAST` so downstream Rust crates can
  consume it without a file lookup. The hand-rolled
  `parse_header`/`write_header` functions remain the hot path; the
  BAST document is the contract.

## [0.1.0] - 2026-08-14

Initial crates.io release. The unification of `alknet-call` (structured
JSON RPC: operations, streaming subscriptions, service discovery) and
`alknet-channels` (multiplexing proxy: N logical channels over one
transport stream, channel 0 pre-negotiated as the call protocol).
Vendored core types (`Connection`, `ProtocolHandler`, `BiStream`,
`BidiStreamSource`, `AuthContext`, `IdentityProvider`, `Capabilities`,
`OwnershipProvider`), the `Pub` operation type / `HandlerKind::Sink`
(ADR-046), the channels protocol with openable-ALPNs-as-operations
(ADR-047), and the `ChannelClient` transport-agnostic client.

[0.8.1]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.8.1
[0.8.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.8.0
[0.7.1]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.7.1
[0.7.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.7.0
[0.6.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.6.0
[0.5.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.5.0
[0.4.1]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.4.1
[0.4.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.4.0
[0.3.1]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.3.1
[0.3.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.3.0
[0.2.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.2.0
[0.1.1]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.1.1
[0.1.0]: https://git.alk.dev/alkdev/alkcall/releases/tag/v0.1.0