docs: align conformance + guides with current message names, ExtensionRegistry, and paired() transport helper

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: nficano

CONFORMANCE.md

@@ -9,10 +9,10 @@ The docs mirror is [`docs/conformance.md`](./docs/conformance.md).
 | --- | --- | --- |
 | §4 Transport | Partial | WebSocket, stdio, and in-memory transports are implemented. HTTP/2 and QUIC are deferred. |
 | §5 Wire format | Full | `Envelope`, `RawEnvelope`, typed payloads, ids, priorities, trace metadata, and extension fields. |
-| §6 Sessions | Full | Session open/accepted/rejected/unauthenticated, bye, lease, ack, heartbeat, job listing, and subscriptions. |
+| §6 Sessions | Full | `session.open` / `accepted` / `rejected` / `unauthenticated` / `close`, lease, ack, heartbeat, job listing, and subscriptions. |
 | §6.1 Authentication | Partial | Bearer, signed JWT, and anonymous auth are implemented. mTLS and OAuth2 are deferred to vendor or future adapters. |
 | §6.3 Resume | Full | SQLite event log supports replay by session and sequence boundary; resumability examples exercise reconnect flows. |
-| §6.4 Heartbeat | Full | `session.heartbeat` / `session.pong` messages and runtime examples are implemented. |
+| §6.4 Heartbeat | Full | `session.ping` / `session.pong` messages and runtime examples are implemented. |
 | §6.5 Ack | Full | Runtime ack window and `session.ack` back-pressure are implemented. |
 | §6.6 List jobs / Subscribe | Full | `session.list_jobs`, `job.subscribe`, `job.unsubscribe`, and generic subscription fanout are implemented. |
 | §7 Jobs | Full | Submit, accept, start, complete, fail, cancel, state inventory, and idempotent retry paths. |
@@ -22,7 +22,7 @@ The docs mirror is [`docs/conformance.md`](./docs/conformance.md).
 | §8 Job events | Full | Reserved event kinds plus vendor event classification are implemented. |
 | §8.2.1 Progress | Full | Progress events are emitted by examples and represented in message types. |
 | §8.3 Sequence numbers | Full | Event log and runtime fanout preserve per-session event sequence ordering. |
-| §8.4 Result chunks | Full | `result.chunk` stream assembly and terminal result references are implemented. |
+| §8.4 Result chunks | Full | `job.result_chunk` stream assembly and terminal result references are implemented. |
 | §9 Leases | Full | Lease request, session lease, subset validation, expiration, budgets, model use, and revocation helpers. |
 | §9.6 Budgets | Full | `cost.budget` tracking emits remaining metrics and returns `BUDGET_EXHAUSTED` on depletion. |
 | §9.7 Model use | Full | `model.use` glob enforcement is implemented in `ToolContext`. |
@@ -31,7 +31,7 @@ The docs mirror is [`docs/conformance.md`](./docs/conformance.md).
 | §11 Observability | Partial | Trace ids and metric/log event payloads are implemented. Native OpenTelemetry middleware is deferred. |
 | §12 Error taxonomy | Full | Canonical codes serialize to wire strings and map to `ARCPError` variants. |
 | §14 Security | Partial | Auth, lease checks, credential redaction, and back-pressure caps are implemented. Host-framework DNS-rebind helpers are out of scope for this crate. |
-| §15 Vendor extensions | Full | `x-vendor.*` validation, classification, and round-trip handling are implemented. |
+| §15 IANA / extensions | Full | `arcpx.*` and reverse-DNS extension namespace validation, advertised-vs-unknown classification, and round-trip handling are implemented in `ExtensionRegistry`. |
 | §16 Artifacts | Full | Inline base64 artifact put, fetch, release, retention, and runtime dispatch are implemented. |
 | §22 Standard transports | Partial | WebSocket and stdio are implemented; HTTP/2 and QUIC are deferred. |
 

README.md

@@ -337,21 +337,35 @@ match run_job(&transport, session_id.clone()).await {
 
 ## Feature support
 
-ARCP features this SDK negotiates during the `hello`/`welcome` handshake:
+`Capabilities` (RFC §7) is the negotiated feature set, exchanged on
+`session.open` / `session.accepted`. The Rust SDK implements the following
+capability fields:
 
-| Feature flag | Status |
+| `Capabilities` field | Status |
 |---|---|
-| `heartbeat` | Supported |
-| `ack` | Supported |
-| `list_jobs` | Supported |
-| `subscribe` | Supported |
-| `lease_expires_at` | Supported |
-| `cost.budget` | Supported |
-| `model.use` | Supported |
+| `streaming` | Supported |
+| `durable_jobs` | Supported |
+| `checkpoints` | Not implemented (deferred) |
+| `binary_streams` | Not implemented (deferred) |
+| `agent_handoff` | Supported |
+| `model_use` | Supported |
 | `provisioned_credentials` | Supported |
-| `progress` | Supported |
-| `result_chunk` | Supported |
-| `agent_versions` | Supported |
+| `artifacts` | Supported |
+| `subscriptions` | Supported |
+| `scheduled_jobs` | Not implemented (deferred) |
+| `interrupt` | Supported |
+| `anonymous` | Supported |
+| `heartbeat_recovery` | Supported (`"fail"` / `"block"`) |
+| `binary_encoding` | Advertised; payloads remain JSON |
+| `extensions` | Supported |
+| `artifact_retention` | Supported |
+| `agents` | Supported (v1.0 flat list and v1.1 rich form) |
+
+The SDK also implements the ARCP v1.1 protocol-level surfaces that are not
+themselves capability flags: `session.ack` flow control (§6.5),
+`session.ping`/`pong` heartbeats (§6.4), `session.list_jobs` (§6.6),
+`job.subscribe`/`job.unsubscribe` (§7.6), `job.progress`,
+`job.result_chunk` (§8.4), and `agent@version` resolution (§7.5).
 
 ## Transport
 

docs/diagrams/architecture-dark.dot

@@ -23,6 +23,14 @@ digraph RustSdkArchitecture {
     label=<<FONT POINT-SIZE="11"><B>arcp::messages</B></FONT><BR/><FONT POINT-SIZE="9" COLOR="#94A3B8">tagged-enum MessageType</FONT>>
   ];
 
+  Envelope [
+    label=<<FONT POINT-SIZE="11"><B>arcp::envelope</B></FONT><BR/><FONT POINT-SIZE="9" COLOR="#94A3B8">Envelope · ids · trace · priority</FONT>>
+  ];
+
+  Auth [
+    label=<<FONT POINT-SIZE="11"><B>arcp::auth</B></FONT><BR/><FONT POINT-SIZE="9" COLOR="#94A3B8">bearer · jwt · none</FONT>>
+  ];
+
   subgraph cluster_transport {
     label=<<TABLE BORDER="0" CELLBORDER="0" CELLPADDING="0" CELLSPACING="0"><TR><TD COLSPAN="3" HEIGHT="8"></TD></TR><TR><TD WIDTH="8"></TD><TD><FONT POINT-SIZE="12"><B>arcp::transport</B></FONT></TD><TD WIDTH="8"></TD></TR></TABLE>>;
     style="rounded,filled";
@@ -47,8 +55,10 @@ digraph RustSdkArchitecture {
   Client   -> Runtime  [dir=both, label="invoke / events"];
   Client   -> Messages;
   Runtime  -> Messages;
-  Messages -> Ws       [lhead=cluster_transport];
+  Messages -> Envelope [label="wrapped in"];
+  Envelope -> Ws       [lhead=cluster_transport];
 
   edge [color="#475569", penwidth=1.0];
+  Runtime -> Auth;
   Runtime -> Store;
 }