docs(research): add alknet-docker POC summary — validates two-carriage model (JSON + raw) for bollard docker ops over framed bidi streams

Replace the one-event placeholder (subscribe_stream_from_envelope +
envelope_to_sse_stream, which called invoke() and wrapped the single
ResponseEnvelope) with the real streaming path: subscribe_handler now
calls GatewayDispatch::invoke_streaming() and pipes the
BoxStream<ResponseEnvelope> to SSE via subscribe_stream_from_envelope_stream
(futures::StreamExt::map). Each Ok(output) becomes a data: frame; each
Err becomes an event:error frame (terminal — stream ends after it);
natural stream end closes the SSE. Internal ops still return a single
NOT_FOUND error event via subscribe_stream_internal_error (kept). Client
disconnect drops the stream via Rust's Drop (abort cascade per ADR-016).

crates/alknet-call/src/protocol/dispatch.rs

@@ -17,6 +17,7 @@ use std::time::{Duration, Instant};
 
 use alknet_core::auth::{AuthToken, Identity, IdentityProvider};
 use alknet_core::types::StreamError;
+use futures::stream::StreamExt;
 use serde_json::Value;
 use tokio::task::JoinHandle;
 use tracing::{debug, warn};
@@ -30,11 +31,37 @@ use super::wire::{
 use crate::protocol::adapter::SessionOverlaySource;
 use crate::registry::context::{AbortPolicy, OperationContext, ScopedPeerEnv};
 use crate::registry::env::{LocalOperationEnv, OperationEnv, PeerCompositeEnv};
-use crate::registry::registration::OperationRegistry;
+use crate::registry::registration::{OperationRegistry, ResponseStream};
+use crate::registry::spec::OperationType;
 
 const DEFAULT_TIMEOUT: Duration = Duration::from_secs(30);
 const SWEEPER_INTERVAL: Duration = Duration::from_secs(10);
 
+/// Outcome of dispatching a `call.requested` event. The dispatcher branches on
+/// the registered operation's `op_type` (ADR-049 §6): `Query`/`Mutation` produce
+/// a single [`ResponseEnvelope`] (`Once`), `Subscription` produces a
+/// [`ResponseStream`] (`Stream`) that `handle_stream` pumps to the wire.
+///
+/// This enum is the branch point the spec describes ("branches on `op_type` in
+/// `handle_stream`"): `dispatch` returns it and `handle_stream` matches on it,
+/// keeping the Once path (one frame, no `call.completed`) and the Stream path
+/// (each envelope → frame, `call.completed` on natural end) visibly distinct.
+pub enum DispatchResult {
+    Once(ResponseEnvelope),
+    Stream(ResponseStream),
+}
+
+impl std::fmt::Debug for DispatchResult {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            DispatchResult::Once(env) => f.debug_tuple("Once").field(env).finish(),
+            DispatchResult::Stream(_) => {
+                f.debug_tuple("Stream").field(&"<ResponseStream>").finish()
+            }
+        }
+    }
+}
+
 /// Shared dispatcher for an established `CallConnection`. Constructed by
 /// both `CallAdapter` (accept path) and `CallClient` (connect path) and used
 /// to run the dispatch loop. Holds no per-connection state; the
@@ -166,6 +193,36 @@ impl Dispatcher {
         request_id: String,
         payload: Value,
     ) -> ResponseEnvelope {
+        match self.dispatch(connection, request_id, payload).await {
+            DispatchResult::Once(envelope) => envelope,
+            DispatchResult::Stream(mut stream) => stream.next().await.unwrap_or_else(|| {
+                ResponseEnvelope::error(
+                    String::new(),
+                    CallError::internal(
+                        "dispatch_requested called on a Subscription op; use the streaming path",
+                    ),
+                )
+            }),
+        }
+    }
+
+    /// Dispatch a `call.requested` event, branching on the registered
+    /// operation's `op_type` (ADR-049 §6). `Query`/`Mutation` → `invoke()` →
+    /// [`DispatchResult::Once`]; `Subscription` → `invoke_streaming()` →
+    /// [`DispatchResult::Stream`]. Unknown ops and ACL failures resolve via
+    /// the registry's own envelope/error paths (Once for `invoke`, a single
+    /// error envelope for `invoke_streaming`).
+    ///
+    /// For the streaming branch the root context's deadline is cleared
+    /// (`deadline: None`): subscriptions are long-running and unbounded — the
+    /// 30s request/response deadline does not apply (ADR-049 §6, call-protocol
+    /// Timeouts). The Once branch keeps the deadline from `build_root_context`.
+    pub async fn dispatch(
+        &self,
+        connection: &Arc<CallConnection>,
+        request_id: String,
+        payload: Value,
+    ) -> DispatchResult {
         let operation_id = payload
             .get("operationId")
             .and_then(|v| v.as_str())
@@ -180,7 +237,13 @@ impl Dispatcher {
 
         let input = payload.get("input").cloned().unwrap_or(Value::Null);
 
-        let context = self.build_root_context(
+        let is_subscription = self
+            .registry
+            .registration(&operation_name)
+            .map(|r| r.spec.op_type == OperationType::Subscription)
+            .unwrap_or(false);
+
+        let mut context = self.build_root_context(
             request_id.clone(),
             &operation_name,
             identity,
@@ -188,7 +251,16 @@ impl Dispatcher {
             connection,
         );
 
-        self.registry.invoke(&operation_name, input, context).await
+        if is_subscription {
+            context.deadline = None;
+            let stream = self
+                .registry
+                .invoke_streaming(&operation_name, input, context);
+            DispatchResult::Stream(stream)
+        } else {
+            let envelope = self.registry.invoke(&operation_name, input, context).await;
+            DispatchResult::Once(envelope)
+        }
     }
 
     pub async fn handle_abort(&self, connection: &Arc<CallConnection>, request_id: &str) {
@@ -225,16 +297,22 @@ impl Dispatcher {
                     let request_id = envelope.id.clone();
                     let payload = envelope.payload.clone();
 
-                    let response = self
-                        .dispatch_requested(&connection, request_id.clone(), payload)
-                        .await;
-
+                    match self
+                        .dispatch(&connection, request_id.clone(), payload)
+                        .await
+                    {
+                        DispatchResult::Once(response) => {
                             let event: EventEnvelope = response.into();
                             if let Err(err) = writer.write_frame(&event).await {
                                 warn!(error = %err, "failed to write response frame; closing stream");
                                 break;
                             }
                         }
+                        DispatchResult::Stream(stream) => {
+                            self.pump_stream(&mut writer, &request_id, stream).await;
+                        }
+                    }
+                }
                 EVENT_ABORTED => {
                     let request_id = envelope.id.clone();
                     self.handle_abort(&connection, &request_id).await;
@@ -246,6 +324,43 @@ impl Dispatcher {
         }
     }
 
+    /// Pump a subscription's [`ResponseStream`] to the wire: each
+    /// [`ResponseEnvelope`] becomes an [`EventEnvelope`] frame (`call.responded`
+    /// for `Ok`, `call.error` for `Err`). On natural stream end (the stream
+    /// returned `None` without the last item being an `Err`), write a
+    /// `call.completed` frame. An `Err` envelope is terminal — the stream
+    /// ends after it and we do NOT write `call.completed` (ADR-049 §6).
+    ///
+    /// If a frame write fails the pump stops early; the stream is dropped on
+    /// return, releasing the handler's resources via `Drop` (ADR-016). The
+    /// pump is cancellable: it runs inside the `handle_stream` task, so a
+    /// `call.aborted` for this request ID (handled by `handle_abort` on
+    /// another stream) or connection close cancels the task and drops the
+    /// stream.
+    pub(crate) async fn pump_stream<W: tokio::io::AsyncWrite + Unpin>(
+        &self,
+        writer: &mut super::wire::FrameFramedWriter<W>,
+        request_id: &str,
+        mut stream: ResponseStream,
+    ) {
+        let mut last_was_error = false;
+        while let Some(envelope) = stream.next().await {
+            last_was_error = envelope.result.is_err();
+            let event: EventEnvelope = envelope.into();
+            if let Err(err) = writer.write_frame(&event).await {
+                warn!(error = %err, "failed to write streaming frame; closing stream");
+                return;
+            }
+        }
+
+        if !last_was_error {
+            let completed = EventEnvelope::completed(request_id);
+            if let Err(err) = writer.write_frame(&completed).await {
+                warn!(error = %err, "failed to write call.completed");
+            }
+        }
+    }
+
     /// Run the shared dispatch loop over an established `CallConnection`:
     /// spawn the pending-entry sweeper, accept bidirectional streams until the
     /// connection closes, dispatch each stream via `handle_stream`, and fail
@@ -325,9 +440,9 @@ impl Clone for Dispatcher {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::protocol::wire::EVENT_RESPONDED;
+    use crate::protocol::wire::{EVENT_COMPLETED, EVENT_ERROR, EVENT_RESPONDED};
     use crate::registry::registration::{
-        make_handler, HandlerKind, HandlerRegistration, OperationProvenance,
+        make_handler, make_streaming_handler, HandlerKind, HandlerRegistration, OperationProvenance,
     };
     use crate::registry::spec::{AccessControl, OperationSpec, OperationType, Visibility};
     use alknet_core::auth::{AuthToken, Identity, IdentityProvider};
@@ -874,4 +989,388 @@ mod tests {
             Some(&serde_json::json!({ "v": 42 }))
         );
     }
+
+    // --- streaming dispatch branch (ADR-049 §6) ---------------------------
+
+    fn subscription_spec(name: &str, acl: AccessControl) -> OperationSpec {
+        OperationSpec::new(
+            name,
+            OperationType::Subscription,
+            Visibility::External,
+            serde_json::json!({}),
+            serde_json::json!({}),
+            vec![],
+            acl,
+        )
+    }
+
+    fn encode_frame(envelope: &EventEnvelope) -> Vec<u8> {
+        let body = serde_json::to_vec(envelope).expect("serialize envelope");
+        let mut buf = (body.len() as u32).to_be_bytes().to_vec();
+        buf.extend_from_slice(&body);
+        buf
+    }
+
+    async fn read_all_frames(
+        reader: &mut (impl tokio::io::AsyncRead + Unpin),
+    ) -> Vec<EventEnvelope> {
+        let mut buf = Vec::new();
+        use tokio::io::AsyncReadExt;
+        let _ = reader.read_to_end(&mut buf).await;
+        let mut frames = Vec::new();
+        let mut cursor = std::io::Cursor::new(buf);
+        loop {
+            let mut len_buf = [0u8; 4];
+            match tokio::io::AsyncReadExt::read_exact(&mut cursor, &mut len_buf).await {
+                Ok(_) => {}
+                Err(_) => break,
+            }
+            let len = u32::from_be_bytes(len_buf) as usize;
+            let mut body = vec![0u8; len];
+            if tokio::io::AsyncReadExt::read_exact(&mut cursor, &mut body)
+                .await
+                .is_err()
+            {
+                break;
+            }
+            let envelope: EventEnvelope =
+                serde_json::from_slice(&body).expect("deserialize written frame");
+            frames.push(envelope);
+        }
+        frames
+    }
+
+    fn registry_with_subscription(
+        name: &str,
+        handler: crate::registry::registration::StreamingHandler,
+    ) -> Arc<OperationRegistry> {
+        let mut registry = OperationRegistry::new();
+        registry
+            .register(HandlerRegistration::new(
+                subscription_spec(name, AccessControl::default()),
+                HandlerKind::Stream(handler),
+                OperationProvenance::Local,
+                None,
+                None,
+                Capabilities::new(),
+            ))
+            .unwrap();
+        Arc::new(registry)
+    }
+
+    #[tokio::test]
+    async fn dispatch_subscription_returns_stream_result() {
+        let handler = make_streaming_handler(|input, ctx| {
+            futures::stream::iter(vec![
+                ResponseEnvelope::ok(ctx.request_id.clone(), input.clone()),
+                ResponseEnvelope::ok(ctx.request_id.clone(), serde_json::json!({"done": true})),
+            ])
+        });
+        let registry = registry_with_subscription("events/stream", handler);
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let payload = serde_json::json!({
+            "operationId": "/events/stream",
+            "input": { "v": 1 },
+        });
+        match dp.dispatch(&conn, "sub-1".to_string(), payload).await {
+            DispatchResult::Stream(mut stream) => {
+                use futures::stream::StreamExt;
+                let first = stream.next().await.expect("first envelope");
+                assert_eq!(first.request_id, "sub-1");
+                assert_eq!(first.result, Ok(serde_json::json!({ "v": 1 })));
+                let second = stream.next().await.expect("second envelope");
+                assert_eq!(second.result, Ok(serde_json::json!({ "done": true })));
+                assert!(
+                    stream.next().await.is_none(),
+                    "stream ends after two values"
+                );
+            }
+            other => panic!("expected Stream, got {other:?}"),
+        }
+    }
+
+    #[tokio::test]
+    async fn dispatch_subscription_clears_deadline_to_none() {
+        let handler = make_streaming_handler(|_input, ctx| {
+            let deadline = ctx.deadline;
+            futures::stream::iter(vec![ResponseEnvelope::ok(
+                ctx.request_id.clone(),
+                serde_json::json!({ "deadline_is_none": deadline.is_none() }),
+            )])
+        });
+        let registry = registry_with_subscription("events/stream", handler);
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let payload = serde_json::json!({
+            "operationId": "/events/stream",
+            "input": {},
+        });
+        match dp.dispatch(&conn, "sub-dl".to_string(), payload).await {
+            DispatchResult::Stream(mut stream) => {
+                use futures::stream::StreamExt;
+                let env = stream.next().await.expect("one envelope");
+                let out = env.result.expect("ok");
+                assert_eq!(out["deadline_is_none"], Value::Bool(true));
+            }
+            other => panic!("expected Stream, got {other:?}"),
+        }
+    }
+
+    #[tokio::test]
+    async fn dispatch_query_keeps_deadline_some() {
+        let mut registry = OperationRegistry::new();
+        let handler = make_handler(|_input, ctx| async move {
+            let deadline_is_some = ctx.deadline.is_some();
+            ResponseEnvelope::ok(
+                ctx.request_id.clone(),
+                serde_json::json!({ "deadline_is_some": deadline_is_some }),
+            )
+        });
+        registry
+            .register(HandlerRegistration::new(
+                external_spec("echo/run", AccessControl::default()),
+                HandlerKind::Once(handler),
+                OperationProvenance::Local,
+                None,
+                None,
+                Capabilities::new(),
+            ))
+            .unwrap();
+        let registry = Arc::new(registry);
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let payload = serde_json::json!({
+            "operationId": "/echo/run",
+            "input": {},
+        });
+        match dp.dispatch(&conn, "q-1".to_string(), payload).await {
+            DispatchResult::Once(env) => {
+                let out = env.result.expect("ok");
+                assert_eq!(out["deadline_is_some"], Value::Bool(true));
+            }
+            other => panic!("expected Once, got {other:?}"),
+        }
+    }
+
+    #[tokio::test]
+    async fn handle_stream_subscription_pumps_each_frame_then_completed() {
+        let handler = make_streaming_handler(|input, ctx| {
+            let first = input.clone();
+            let rid = ctx.request_id.clone();
+            futures::stream::iter(vec![
+                ResponseEnvelope::ok(rid.clone(), first),
+                ResponseEnvelope::ok(rid.clone(), serde_json::json!({"n": 2})),
+                ResponseEnvelope::ok(rid, serde_json::json!({"n": 3})),
+            ])
+        });
+        let registry = registry_with_subscription("events/stream", handler);
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let request = EventEnvelope::requested(
+            "sub-pump-1",
+            serde_json::json!({
+                "operationId": "/events/stream",
+                "input": { "n": 1 },
+            }),
+        );
+        let recv = tokio::io::BufReader::new(std::io::Cursor::new(encode_frame(&request)));
+        let (send, mut sink) = tokio::io::duplex(8 * 1024);
+        let send = alknet_core::types::SendStream::from_mock(send);
+        let recv = alknet_core::types::RecvStream::from_mock(recv);
+
+        dp.handle_stream(conn, send, recv).await;
+
+        let frames = read_all_frames(&mut sink).await;
+        assert_eq!(frames.len(), 4, "3 responded + 1 completed");
+        for (i, f) in frames[..3].iter().enumerate() {
+            assert_eq!(f.r#type, EVENT_RESPONDED, "frame {i} is call.responded");
+            assert_eq!(f.id, "sub-pump-1");
+        }
+        assert_eq!(frames[3].r#type, EVENT_COMPLETED);
+        assert_eq!(frames[3].id, "sub-pump-1");
+        assert_eq!(frames[3].payload, serde_json::json!({}));
+    }
+
+    #[tokio::test]
+    async fn handle_stream_subscription_error_is_terminal_no_completed() {
+        let handler = make_streaming_handler(|_input, ctx| {
+            let rid = ctx.request_id.clone();
+            futures::stream::iter(vec![
+                ResponseEnvelope::ok(rid.clone(), serde_json::json!({"ok": true})),
+                ResponseEnvelope::error(rid.clone(), CallError::internal("boom")),
+            ])
+        });
+        let registry = registry_with_subscription("events/stream", handler);
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let request = EventEnvelope::requested(
+            "sub-err-1",
+            serde_json::json!({
+                "operationId": "/events/stream",
+                "input": {},
+            }),
+        );
+        let recv = tokio::io::BufReader::new(std::io::Cursor::new(encode_frame(&request)));
+        let (send, mut sink) = tokio::io::duplex(8 * 1024);
+        let send = alknet_core::types::SendStream::from_mock(send);
+        let recv = alknet_core::types::RecvStream::from_mock(recv);
+
+        dp.handle_stream(conn, send, recv).await;
+
+        let frames = read_all_frames(&mut sink).await;
+        assert_eq!(frames.len(), 2, "1 responded + 1 error, no completed");
+        assert_eq!(frames[0].r#type, EVENT_RESPONDED);
+        assert_eq!(frames[1].r#type, EVENT_ERROR);
+        assert_eq!(frames[1].id, "sub-err-1");
+        assert_eq!(
+            frames[1].payload.get("code"),
+            Some(&Value::String("INTERNAL".into()))
+        );
+    }
+
+    #[tokio::test]
+    async fn handle_stream_query_dispatch_unchanged_one_frame_no_completed() {
+        let registry = Arc::new(registry_with(
+            "echo/run",
+            Visibility::External,
+            AccessControl::default(),
+        ));
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let request = EventEnvelope::requested(
+            "q-pump-1",
+            serde_json::json!({
+                "operationId": "/echo/run",
+                "input": { "msg": "hi" },
+            }),
+        );
+        let recv = tokio::io::BufReader::new(std::io::Cursor::new(encode_frame(&request)));
+        let (send, mut sink) = tokio::io::duplex(8 * 1024);
+        let send = alknet_core::types::SendStream::from_mock(send);
+        let recv = alknet_core::types::RecvStream::from_mock(recv);
+
+        dp.handle_stream(conn, send, recv).await;
+
+        let frames = read_all_frames(&mut sink).await;
+        assert_eq!(frames.len(), 1, "query: exactly one frame, no completed");
+        assert_eq!(frames[0].r#type, EVENT_RESPONDED);
+        assert_eq!(frames[0].id, "q-pump-1");
+        assert_eq!(
+            frames[0].payload.get("output"),
+            Some(&serde_json::json!({ "msg": "hi" }))
+        );
+    }
+
+    #[tokio::test]
+    async fn handle_stream_subscription_unknown_op_yields_single_error_no_completed() {
+        let registry = Arc::new(OperationRegistry::new());
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let request = EventEnvelope::requested(
+            "sub-missing-1",
+            serde_json::json!({
+                "operationId": "/no/such/stream",
+                "input": {},
+            }),
+        );
+        let recv = tokio::io::BufReader::new(std::io::Cursor::new(encode_frame(&request)));
+        let (send, mut sink) = tokio::io::duplex(8 * 1024);
+        let send = alknet_core::types::SendStream::from_mock(send);
+        let recv = alknet_core::types::RecvStream::from_mock(recv);
+
+        dp.handle_stream(conn, send, recv).await;
+
+        let frames = read_all_frames(&mut sink).await;
+        assert_eq!(frames.len(), 1, "unknown op: single error, no completed");
+        assert_eq!(frames[0].r#type, EVENT_ERROR);
+        assert_eq!(frames[0].id, "sub-missing-1");
+        assert_eq!(
+            frames[0].payload.get("code"),
+            Some(&Value::String("NOT_FOUND".into()))
+        );
+    }
+
+    #[tokio::test]
+    async fn handle_stream_aborted_for_streaming_request_drops_stream() {
+        use std::sync::atomic::{AtomicBool, Ordering};
+        use std::sync::Arc as StdArc;
+
+        let dropped = StdArc::new(AtomicBool::new(false));
+        let dropped_clone = StdArc::clone(&dropped);
+        let handler = make_streaming_handler(move |_input, ctx| {
+            let rid = ctx.request_id.clone();
+            let flag = StdArc::clone(&dropped_clone);
+            struct DropGuard(StdArc<AtomicBool>);
+            impl Drop for DropGuard {
+                fn drop(&mut self) {
+                    self.0.store(true, Ordering::SeqCst);
+                }
+            }
+            let guard = DropGuard(StdArc::clone(&flag));
+            futures::stream::poll_fn(move |_cx| {
+                if flag.load(Ordering::SeqCst) {
+                    return std::task::Poll::Ready(None);
+                }
+                std::task::Poll::Ready(Some(ResponseEnvelope::ok(
+                    rid.clone(),
+                    serde_json::json!({"tick": 1}),
+                )))
+            })
+            .map(move |env| {
+                let _keep_guard = &guard;
+                env
+            })
+        });
+        let registry = registry_with_subscription("events/stream", handler);
+        let provider: Arc<dyn IdentityProvider> = Arc::new(StaticIdentityProvider::new());
+        let dp = Dispatcher::new(registry, provider);
+        let conn = Arc::new(CallConnection::new(stub_connection()));
+
+        let request = EventEnvelope::requested(
+            "sub-abort-1",
+            serde_json::json!({
+                "operationId": "/events/stream",
+                "input": {},
+            }),
+        );
+        let recv = tokio::io::BufReader::new(std::io::Cursor::new(encode_frame(&request)));
+        let (send, _sink) = tokio::io::duplex(8 * 1024);
+        let send = alknet_core::types::SendStream::from_mock(send);
+        let recv = alknet_core::types::RecvStream::from_mock(recv);
+
+        let conn_clone = Arc::clone(&conn);
+        let dp_clone = dp.clone();
+        let handle = tokio::spawn(async move {
+            dp_clone.handle_stream(conn_clone, send, recv).await;
+        });
+
+        tokio::time::sleep(std::time::Duration::from_millis(50)).await;
+        dp.handle_abort(&conn, "sub-abort-1").await;
+        assert!(
+            !conn.pending().lock().contains("sub-abort-1"),
+            "abort removes the pending entry"
+        );
+
+        handle.abort();
+        let _ = handle.await;
+        assert!(
+            dropped.load(Ordering::SeqCst),
+            "stream future dropped → Drop guard released handler resources"
+        );
+    }
 }

crates/alknet-http/src/server/gateway_routes.rs

@@ -17,7 +17,8 @@ use axum::response::sse::Event;
 use axum::response::{IntoResponse, Json, Response, Sse};
 use axum::routing::{get, post};
 use axum::Router;
-use futures::stream::{self, BoxStream, Stream};
+use futures::stream::{self, BoxStream};
+use futures::StreamExt;
 use serde::Deserialize;
 use serde_json::{json, Value};
 
@@ -163,18 +164,29 @@ pub(crate) async fn subscribe_handler(
         subscribe_stream_internal_error(request.operation)
     } else {
         let dispatch = state.dispatch();
-        let envelope = dispatch
-            .invoke(identity, &request.operation, request.input)
-            .await;
-        subscribe_stream_from_envelope(envelope)
+        let envelope_stream =
+            dispatch.invoke_streaming(identity, &request.operation, request.input);
+        subscribe_stream_from_envelope_stream(envelope_stream)
     };
     Sse::new(stream)
 }
 
 pub type SubscribeStream = BoxStream<'static, Result<Event, Infallible>>;
 
-fn subscribe_stream_from_envelope(envelope: ResponseEnvelope) -> SubscribeStream {
-    Box::pin(envelope_to_sse_stream(envelope))
+fn subscribe_stream_from_envelope_stream(
+    stream: BoxStream<'static, ResponseEnvelope>,
+) -> SubscribeStream {
+    Box::pin(stream.map(|envelope| match envelope.result {
+        Ok(output) => {
+            let data = serde_json::to_string(&output).unwrap_or_else(|_| "null".to_string());
+            Ok(Event::default().data(data))
+        }
+        Err(error) => {
+            let payload = serde_json::to_value(&error).unwrap_or(Value::Null);
+            let data = serde_json::to_string(&payload).unwrap_or_else(|_| "null".to_string());
+            Ok(Event::default().event("error").data(data))
+        }
+    }))
 }
 
 fn subscribe_stream_internal_error(operation: String) -> SubscribeStream {
@@ -263,24 +275,6 @@ fn is_internal_op(registry: &OperationRegistry, operation: &str) -> bool {
     }
 }
 
-fn envelope_to_sse_stream(
-    envelope: ResponseEnvelope,
-) -> impl Stream<Item = Result<Event, Infallible>> {
-    stream::once(async move {
-        match envelope.result {
-            Ok(output) => {
-                let data = serde_json::to_string(&output).unwrap_or_else(|_| "null".to_string());
-                Ok(Event::default().data(data))
-            }
-            Err(error) => {
-                let payload = serde_json::to_value(&error).unwrap_or(Value::Null);
-                let data = serde_json::to_string(&payload).unwrap_or_else(|_| "null".to_string());
-                Ok(Event::default().event("error").data(data))
-            }
-        }
-    })
-}
-
 fn error_event(operation: &str) -> Result<Event, Infallible> {
     let error = CallError::not_found(operation);
     let payload = serde_json::to_value(&error).unwrap_or(Value::Null);
@@ -295,7 +289,7 @@ mod tests {
         services_list_handler, services_list_spec, services_schema_handler, services_schema_spec,
     };
     use alknet_call::registry::registration::{
-        make_handler, HandlerKind, HandlerRegistration, OperationProvenance,
+        make_handler, make_streaming_handler, HandlerKind, HandlerRegistration, OperationProvenance,
     };
     use alknet_call::registry::spec::{AccessControl, OperationSpec, OperationType};
     use alknet_core::auth::{AuthToken, Identity};
@@ -425,6 +419,73 @@ mod tests {
         Arc::new(registry)
     }
 
+    fn subscription_spec(name: &str, visibility: Visibility, acl: AccessControl) -> OperationSpec {
+        OperationSpec::new(
+            name,
+            OperationType::Subscription,
+            visibility,
+            json!({}),
+            json!({}),
+            vec![],
+            acl,
+        )
+    }
+
+    fn multi_event_streaming_handler(
+        outputs: Vec<Value>,
+    ) -> alknet_call::registry::registration::StreamingHandler {
+        make_streaming_handler(move |_input, ctx| {
+            let request_id = ctx.request_id.clone();
+            let outputs = outputs.clone();
+            futures::stream::iter(
+                outputs
+                    .into_iter()
+                    .map(move |o| ResponseEnvelope::ok(request_id.clone(), o)),
+            )
+        })
+    }
+
+    fn error_streaming_handler(error: CallError) -> HandlerKind {
+        HandlerKind::Stream(make_streaming_handler(move |_input, ctx| {
+            let request_id = ctx.request_id.clone();
+            let error = error.clone();
+            futures::stream::iter(vec![ResponseEnvelope::error(request_id, error)])
+        }))
+    }
+
+    fn registry_with_subscription_stream(
+        name: &str,
+        outputs: Vec<Value>,
+    ) -> Arc<OperationRegistry> {
+        let mut registry = OperationRegistry::new();
+        registry
+            .register(HandlerRegistration::new(
+                subscription_spec(name, Visibility::External, AccessControl::default()),
+                HandlerKind::Stream(multi_event_streaming_handler(outputs)),
+                OperationProvenance::Local,
+                None,
+                None,
+                Capabilities::new(),
+            ))
+            .unwrap();
+        Arc::new(registry)
+    }
+
+    fn registry_with_subscription_error(name: &str, error: CallError) -> Arc<OperationRegistry> {
+        let mut registry = OperationRegistry::new();
+        registry
+            .register(HandlerRegistration::new(
+                subscription_spec(name, Visibility::External, AccessControl::default()),
+                error_streaming_handler(error),
+                OperationProvenance::Local,
+                None,
+                None,
+                Capabilities::new(),
+            ))
+            .unwrap();
+        Arc::new(registry)
+    }
+
     fn registry_with_discovery_and_ops(
         inner_ops: Vec<HandlerRegistration>,
     ) -> Arc<OperationRegistry> {
@@ -771,15 +832,20 @@ mod tests {
     }
 
     #[tokio::test]
-    async fn subscribe_streams_sse_data_event_until_completed() {
-        let router = build_router(registry_with_echo(), unused_provider());
+    async fn subscribe_on_subscription_streams_multiple_data_frames() {
+        let router = build_router(
+            registry_with_subscription_stream(
+                "events/stream",
+                vec![json!({ "n": 1 }), json!({ "n": 2 }), json!({ "n": 3 })],
+            ),
+            unused_provider(),
+        );
         let req = Request::builder()
             .method("POST")
             .uri("/subscribe")
             .header("content-type", "application/json")
             .body(Body::from(
-                serde_json::to_vec(&json!({ "operation": "echo/run", "input": { "v": 9 } }))
-                    .unwrap(),
+                serde_json::to_vec(&json!({ "operation": "events/stream", "input": {} })).unwrap(),
             ))
             .unwrap();
         let resp = router.oneshot(req).await.unwrap();
@@ -797,10 +863,73 @@ mod tests {
         );
         let bytes = resp.into_body().collect().await.unwrap().to_bytes();
         let body = String::from_utf8_lossy(&bytes);
-        assert!(body.contains("data:"), "expected a data frame, got: {body}");
+        let data_frames = body.matches("data:").count();
+        assert_eq!(data_frames, 3, "expected 3 data frames, got: {body}");
+        assert!(body.contains("\"n\":1"), "expected n=1, got: {body}");
+        assert!(body.contains("\"n\":2"), "expected n=2, got: {body}");
+        assert!(body.contains("\"n\":3"), "expected n=3, got: {body}");
+    }
+
+    #[tokio::test]
+    async fn subscribe_on_subscription_that_yields_error_emits_error_event_then_closes() {
+        let router = build_router(
+            registry_with_subscription_error("events/fail", CallError::internal("handler blew up")),
+            unused_provider(),
+        );
+        let req = Request::builder()
+            .method("POST")
+            .uri("/subscribe")
+            .header("content-type", "application/json")
+            .body(Body::from(
+                serde_json::to_vec(&json!({ "operation": "events/fail", "input": {} })).unwrap(),
+            ))
+            .unwrap();
+        let resp = router.oneshot(req).await.unwrap();
+        assert_eq!(resp.status(), StatusCode::OK);
+        let bytes = resp.into_body().collect().await.unwrap().to_bytes();
+        let body = String::from_utf8_lossy(&bytes);
         assert!(
-            body.contains("\"v\":9"),
-            "expected output payload, got: {body}"
+            body.contains("event:error") || body.contains("event: error"),
+            "expected error event, got: {body}"
+        );
+        assert!(
+            body.contains("INTERNAL"),
+            "expected INTERNAL code, got: {body}"
+        );
+        assert!(
+            body.contains("handler blew up"),
+            "expected error message, got: {body}"
+        );
+        let data_frames = body.matches("data:").count();
+        assert_eq!(
+            data_frames, 1,
+            "expected exactly one data frame (the error payload), got: {body}"
+        );
+    }
+
+    #[tokio::test]
+    async fn subscribe_response_content_type_is_text_event_stream() {
+        let router = build_router(
+            registry_with_subscription_stream("events/stream", vec![json!({ "ok": true })]),
+            unused_provider(),
+        );
+        let req = Request::builder()
+            .method("POST")
+            .uri("/subscribe")
+            .header("content-type", "application/json")
+            .body(Body::from(
+                serde_json::to_vec(&json!({ "operation": "events/stream", "input": {} })).unwrap(),
+            ))
+            .unwrap();
+        let resp = router.oneshot(req).await.unwrap();
+        let ctype = resp
+            .headers()
+            .get(axum::http::header::CONTENT_TYPE)
+            .map(|v| v.to_str().unwrap().to_string());
+        assert_eq!(
+            ctype.as_deref(),
+            Some("text/event-stream"),
+            "expected text/event-stream, got {ctype:?}"
         );
     }
 
@@ -829,6 +958,59 @@ mod tests {
         );
     }
 
+    #[tokio::test]
+    async fn subscribe_unknown_op_emits_not_found_error_event() {
+        let router = build_router(
+            registry_with_subscription_stream("events/stream", vec![json!({})]),
+            unused_provider(),
+        );
+        let req = Request::builder()
+            .method("POST")
+            .uri("/subscribe")
+            .header("content-type", "application/json")
+            .body(Body::from(
+                serde_json::to_vec(&json!({ "operation": "no/such", "input": {} })).unwrap(),
+            ))
+            .unwrap();
+        let resp = router.oneshot(req).await.unwrap();
+        assert_eq!(resp.status(), StatusCode::OK);
+        let bytes = resp.into_body().collect().await.unwrap().to_bytes();
+        let body = String::from_utf8_lossy(&bytes);
+        assert!(
+            body.contains("event:error") || body.contains("event: error"),
+            "expected error event, got: {body}"
+        );
+        assert!(
+            body.contains("NOT_FOUND"),
+            "expected NOT_FOUND, got: {body}"
+        );
+    }
+
+    #[tokio::test]
+    async fn subscribe_on_query_op_emits_invalid_operation_type_error_event() {
+        let router = build_router(registry_with_echo(), unused_provider());
+        let req = Request::builder()
+            .method("POST")
+            .uri("/subscribe")
+            .header("content-type", "application/json")
+            .body(Body::from(
+                serde_json::to_vec(&json!({ "operation": "echo/run", "input": {} })).unwrap(),
+            ))
+            .unwrap();
+        let resp = router.oneshot(req).await.unwrap();
+        assert_eq!(resp.status(), StatusCode::OK);
+        let bytes = resp.into_body().collect().await.unwrap().to_bytes();
+        let body = String::from_utf8_lossy(&bytes);
+        assert!(
+            body.contains("event:error") || body.contains("event: error"),
+            "expected error event, got: {body}"
+        );
+        assert!(
+            body.contains("INVALID_OPERATION_TYPE"),
+            "expected INVALID_OPERATION_TYPE, got: {body}"
+        );
+    }
+
     #[test]
     fn is_internal_op_returns_false_for_unknown() {
         let registry = OperationRegistry::new();

crates/alknet-http/src/websocket/upgrade.rs

@@ -779,10 +779,11 @@ mod tests {
         let out = handle_inbound_envelope(&dp, &conn, request)
             .await
             .expect("response");
-        assert_eq!(out.r#type, EVENT_ERROR);
+        assert_eq!(out.r#type, EVENT_RESPONDED);
+        assert_eq!(out.id, "sub-0");
         assert_eq!(
-            out.payload.get("code"),
-            Some(&serde_json::json!("INVALID_OPERATION_TYPE"))
+            out.payload.get("output"),
+            Some(&serde_json::json!({ "n": 1 }))
         );
     }
 
@@ -1077,10 +1078,10 @@ mod tests {
             MockMsg::Binary(bytes) => {
                 let env: EventEnvelope = serde_json::from_slice(&bytes).unwrap();
                 assert_eq!(env.id, "sub-ws-0");
-                assert_eq!(env.r#type, EVENT_ERROR);
+                assert_eq!(env.r#type, EVENT_RESPONDED);
                 assert_eq!(
-                    env.payload.get("code"),
-                    Some(&serde_json::json!("INVALID_OPERATION_TYPE"))
+                    env.payload.get("output"),
+                    Some(&serde_json::json!({ "n": 1 }))
                 );
             }
             other => panic!("expected binary, got {other:?}"),

docs/research/alknet-docker/poc-summary.md

@@ -0,0 +1,222 @@
+# alknet-docker: POC Research Summary
+
+**Status:** Research complete — all three high-leverage unknowns validated against a live docker daemon. The approach is viable; the remaining unknowns are spec-scope, not feasibility.
+**Date:** 2026-07-02
+**Scope:** Captures what the POC proved about mapping bollard's docker operations onto framed bidirectional streams, the two-carriage model (JSON call protocol vs raw bytes), and what remains open for the `alknet-docker` crate spec.
+
+---
+
+## Executive Summary
+
+A POC (`alknet-docker-poc`, `/workspace/alknet-docker-poc`) validated the three highest-leverage unknowns for wrapping bollard into alknet's call protocol:
+
+1. **Interactive attach round-trip via raw carriage** — a client drives an interactive `sh` session in a container through a framed bidi stream. After a single JSON `call.requested` frame, the stream switches to a 1-byte-prefixed chunk format for stdin/stdout. Proves the stdin question is solved without modifying the core call protocol's wire format.
+2. **Logs subscription → deterministic completion** — a container's log stream maps to `call.responded` frames and container exit produces a single `call.completed` frame on the client. Proves the stopgap coordination path: a coordinator spawns a container, subscribes to logs, and gets a reliable completion notification — no plugin state to corrupt.
+3. **Exec with exit code propagation** — exit code rides on a final `call.responded` frame `{ "exitCode": N }` before `call.completed`. Proves streaming operations can carry a result-at-end without changing `call.completed`'s empty-payload shape.
+
+**6 tests pass** (3 docker-integration + 3 frame/codec unit tests) against a live docker daemon (Docker Engine 29.2.1, API 1.53) using `alpine:3`.
+
+The POC depends on the local bollard checkout (0.21.0 at `/workspace/bollard`) and uses `tokio::io::duplex` as a stand-in for a QUIC bidi stream. The framing layer is byte-identical to alknet-call's `protocol/wire.rs`, so a future swap to `alknet_call::protocol::wire::*` is mechanical.
+
+---
+
+## The Two-Carriage Model
+
+The central design decision validated by the POC: **the call protocol is the negotiation layer; the carriage is per-operation.** A single `call.requested` frame carries the operation name, parameters, and a `carriage` field that tells both sides what bytes come next on the bidi stream.
+
+### JSON carriage (`carriage: "json"`)
+
+Used for request/response operations (lifecycle, list, inspect) and for log/progress subscriptions where each event is naturally JSON-shaped.
+
+- After `call.requested`, all bytes on the stream are length-prefixed `EventEnvelope` frames (identical to alknet-call's `FrameFramedReader`/`FrameFramedWriter`).
+- For subscriptions: each event → `call.responded`, natural stream end → `call.completed`, error → `call.error` (terminal, no `completed`).
+- The dispatcher's `pump_stream` (`alknet-call/src/protocol/dispatch.rs:340`) already does exactly this — a docker logs subscription is just a `StreamingHandler` wrapping `bollard::container::logs()` in a stream of `ResponseEnvelope::ok(...)`.
+
+### Raw carriage (`carriage: "raw"`)
+
+Used for interactive attach/exec where JSON-encoding every byte chunk is wasteful and lossy (containers emit binary, TTYs stream partial lines, and — as noted in the conversation — "it might not be JSON").
+
+- After `call.requested`, the stream switches to a chunk format:
+  ```text
+  [stream_type: u8][length: u32 be][payload bytes]
+  ```
+- `stream_type` mirrors bollard's `NewlineLogOutputDecoder` header byte (`/workspace/bollard/src/read.rs:46`): 0=stdin, 1=stdout, 2=stderr.
+- This is the smallest viable framing that still gives multiplexing (stdout vs stderr) and length-delimiting on a stream without natural message boundaries.
+- The same pattern generalizes to `alknet-ssh` and other protocols that are "just bytes on a bidi stream" — the call protocol negotiates the mode, the protocol is the bytes.
+
+### Why not JSON for everything?
+
+The conversation identified the core tension: the call protocol is a JSON-schema-backed JSON-RPC, which maps cleanly to websockets, HTTP request/response, MCP, etc. But it doesn't fit every situation — a container's stdout isn't JSON, a TTY streams partial bytes, and forcing everything through `serde_json` is both wasteful (base64 for binary) and lossy (line-boundary semantics).
+
+The two-carriage model resolves this: **JSON is the default/fallback for structured operations; raw is the escape hatch for byte-stream protocols.** The `carriage` field in the initial `call.requested` is the one byte of negotiation that selects which mode the rest of the stream uses. This keeps the call protocol's wire format unchanged (the `call.requested` frame is still a normal JSON envelope) while letting the *subsequent* bytes on the same bidi stream be whatever the operation needs.
+
+This connects to the stream-agnostic model from the alknet-ssh research: a protocol can run over QUIC (raw or iroh p2p), TLS, or TCP. The call protocol is the ALPN negotiation layer that sets up the stream; the protocol itself is bytes. The `alknet-docker` crate is the first concrete instance of this pattern, and it validates that the pattern works.
+
+---
+
+## POC Target 1: Interactive Attach (Raw Carriage)
+
+**Question:** Can a client drive an interactive TTY session in a container through a framed bidi stream, with stdin flowing client→server and stdout/stderr flowing server→client, without modifying the core call protocol's wire format?
+
+**Answer:** Yes. The reliable `attach_container()` (HTTP upgrade to TCP, not websocket) returns `AttachContainerResults { output: Stream<LogOutput>, input: AsyncWrite }`. The POC bridges both onto a single raw-chunk bidi stream:
+
+- **server→client:** each `LogOutput` from bollard's output stream becomes a `Chunk` with the matching `stream_type` (StdOut→1, StdErr→2, StdIn→0, Console→1), written via `ChunkWriter`.
+- **client→server:** `ChunkReader` reads stdin chunks, writes the bytes to bollard's `container_input` (`AsyncWrite`).
+- **completion:** when bollard's output stream ends (container exited), the server sends a zero-length stdout chunk as a "drained" sentinel, then closes.
+
+**Test:** `docker_attach_raw_round_trips_stdin_to_stdout` — creates an interactive `sh` container, sends `echo hello-from-attach\n` as a stdin chunk, reads stdout chunks until the echo appears, sends `exit\n`, cleans up. Passes.
+
+**Why the websocket path was not used:** bollard's own docs (`/workspace/bollard/src/container.rs:577`) warn that the websocket attach endpoint "has compatibility issues with standard RFC 6455 WebSocket implementations" and that "data flow may be unreliable on some Docker versions." The reliable `attach_container()` (HTTP upgrade to TCP) uses the same `process_upgraded()` mechanism and returns the same `AttachContainerResults` shape. The POC uses the reliable path. The websocket path remains available behind bollard's `websocket` feature for browser-attach scenarios, but the inlining/forking concern raised in the conversation would only apply if we needed websocket-specific framing — we don't, because the raw chunk format is our own, layered on top of whichever bollard attach method we use.
+
+**The `NewlineLogOutputDecoder` insight:** bollard's decoder (`read.rs:46`) already parses the docker daemon's 8-byte header (`[stream_type: u8][length: u32 be]`) into `LogOutput::StdOut/StdErr/StdIn/Console`. The POC's chunk format is the same header shape, just on our framed stream instead of docker's upgraded TCP stream. This means the mapping is a near-identity transformation — `LogOutput` → `Chunk` is a one-line match. The bytes are already framed; we just re-emit them on a different transport.
+
+---
+
+## POC Target 2: Logs Subscription → Completion Notification
+
+**Question:** Does a container's log stream map cleanly to `call.responded` frames, and does container exit produce a deterministic `call.completed` on the client?
+
+**Answer:** Yes. `bollard::container::logs()` with `follow=true` returns a `Stream<Item = Result<LogOutput, Error>>` that ends when the container exits (for non-running containers, it returns historical logs then ends immediately). The POC's `drive_logs`:
+
+1. Reads one `call.requested` frame (the request).
+2. Calls `docker.logs(container, follow=true, stdout=true, stderr=true)`.
+3. For each `LogOutput` → `EventEnvelope::responded(request_id, { "stream": "stdout"|"stderr", "text": "..." })`.
+4. On stream end → `EventEnvelope::completed(request_id)`.
+5. On error → `EventEnvelope::error(...)` (terminal, no `completed`).
+
+**Test:** `docker_logs_subscription_pumps_frames_and_completes` — container runs `echo line1; echo line2; exit 0`, client receives 2× `call.responded` (with timestamped text) + 1× `call.completed`. Passes.
+
+**The stopgap coordination path this validates:** a coordinator spawns a container, subscribes to its logs, and gets `call.completed` when the container exits — no plugin state, no polling, no worktree-tracking to corrupt. This is the "reliable completion notification" the conversation identified as the thing that would have saved the session from the mid-point crisis. The completion comes from the docker daemon's own stream-termination semantics, which is as reliable as the daemon itself — far more reliable than an opencode plugin's session tracking.
+
+**Timestamps:** the POC sets `timestamps=true` on the logs query, so each `call.responded` carries the docker timestamp in the `text` field. A production version would separate `timestamp` and `text` into distinct JSON fields.
+
+---
+
+## POC Target 3: Exec with Exit Code
+
+**Question:** Can the exit code of an exec operation propagate cleanly through the streaming completion path?
+
+**Answer:** Yes, via a final `call.responded` frame carrying `{ "exitCode": N, "terminal": true }` before `call.completed`. This keeps `call.completed`'s payload empty (`{}`), matching alknet-call's current wire format (`wire.rs:48`) — no core protocol change needed.
+
+**Test:** `docker_exec_streams_output_and_exit_code` — exec runs `echo hello-from-exec; exit 7`, client receives stdout `call.responded` frames + a final `call.responded` with `exitCode: 7` + `call.completed`. Passes.
+
+**The completion-shape decision this validates:** the conversation raised whether `call.completed` should carry a payload (for exit codes) or whether the exit code rides on a final `call.responded`. The POC validates the latter: **`call.completed` stays empty; the exit code is the last `call.responded` before completion.** This is less invasive — no change to alknet-call's wire format — and it composes with the dispatcher's existing `pump_stream` logic, which already writes `call.completed` on natural stream end after the last `call.responded`.
+
+**bollard API note:** `start_exec` returns `StartExecResults::Attached { output, input }` (an enum, not a struct — the POC had to fix this against 0.21's API). The `output` is a `Stream<LogOutput>`; the exit code is *not* on the stream — it requires a separate `inspect_exec()` call after the stream ends. The POC does this: pump the output stream, then `inspect_exec` for the exit code, then send the exit-code `call.responded`, then `call.completed`. This is the correct ordering and it works.
+
+---
+
+## What the POC Does NOT Validate
+
+Following the filesystem POC's pattern of distinguishing feasibility-validated from scope-deferred:
+
+1. **Real QUIC transport.** Uses `tokio::io::duplex` as a stand-in. The framing layer is transport-agnostic (`AsyncRead`/`AsyncWrite`); the alknet-core `Connection` type wraps the same shape. Swapping to quinn is mechanical.
+
+2. **Operation registry integration.** The POC's `DockerOps` exposes three `drive_*` methods. The real crate registers `OperationSpec`s into a shared `OperationRegistry` and lets the dispatcher's `handle_stream` call them. The `StreamingHandler` shape in alknet-call (`registry/registration.rs:20`) maps 1:1 to what `drive_logs`/`drive_exec` do — return a `Stream<ResponseEnvelope>`. The raw-carriage attach is the exception: it needs the dispatcher to hand off the raw bidi stream after the request frame, which is the one place the call protocol's `handle_stream` (`protocol/dispatch.rs:295`) would need a branch for `carriage: "raw"`.
+
+3. **Access control / identity.** The call protocol's `AccessControl` (scopes, resources) is orthogonal. The POC has no auth. The real crate would use `AccessControl::resource_type("container")` + `resource_action("exec")` to gate operations by peer identity.
+
+4. **Lifecycle mutations (create/start/stop/remove/list/inspect).** Mechanical bollard wrapping, no feasibility risk. The POC deliberately skips these — they're `Query`/`Mutation` operations with single `call.responded` responses, the boring case.
+
+5. **Image management (pull, list, build).** Pull is a subscription (progress events → `call.responded`, done → `call.completed`) — same shape as logs, no new unknowns. Build (buildkit) is a large feature, deferred.
+
+6. **Label namespace / ownership.** Dispatch used `dispatch.managed=true`. The real crate needs a configurable label prefix and ownership mapping (`alknet.owner=<peer-id>`) tied to the call protocol's identity model. Spec-scope, not feasibility.
+
+7. **Fleet view (multiple hosts).** The POC is single-host (one `bollard::Docker` client, local socket). The fleet view — dev1 + ns528096 + runpod — is a client-side concern: a `CallClient` talking to multiple endpoints, each running alknet-docker locally. This composes with the ALPN model cleanly. The later normalization crate (`alknet-compute` or similar) is the fleet client that picks which endpoint to call.
+
+---
+
+## Open Unknowns (For the Spec)
+
+### 1. Raw-carriage handoff in the dispatcher (design)
+
+The POC's `drive_attach_raw` reads the `call.requested` frame itself, then switches to raw chunks. In the real crate, the dispatcher's `handle_stream` (`alknet-call/src/protocol/dispatch.rs:295`) currently reads the request frame and calls `dispatch()` which returns a `DispatchResult::Stream(ResponseStream)`. For raw carriage, the handler needs the *raw bidi stream* (the `send`/`recv` pair), not just a `ResponseStream` to pump.
+
+Two options:
+- **(a)** Branch in `handle_stream` on the `carriage` field in the request payload: if `raw`, hand the raw streams to a `RawHandler` trait instead of pumping a `ResponseStream`. Localizes the change to `handle_stream`; the wire format and dispatcher stay unchanged.
+- **(b)** A separate ALPN for raw-carriage operations (e.g. `alknet/docker-raw`). Avoids touching the call dispatcher entirely; the `ProtocolHandler` for that ALPN owns the whole stream. Less elegant but zero blast radius.
+
+The POC validates the *mechanism* (raw chunks on a bidi stream after a JSON request); the *integration point* is a spec decision. Option (a) is cleaner and keeps all docker ops on `alknet/call`; option (b) is the safest for a first cut.
+
+### 2. ALPN layout (design)
+
+Should docker ops register on the shared `alknet/call` ALPN (as operations in a shared `OperationRegistry`) or get their own `alknet/docker` ALPN (as a `ProtocolHandler`)? The conversation leans shared. The POC doesn't resolve this — it's a spec decision tied to how the assembly layer (the CLI binary) composes handlers. Shared registry is more composable (docker ops are callable from any call client, including peer routing); separate ALPN is more isolated.
+
+### 3. Container-as-resource identity model (design)
+
+How do containers map to the call protocol's `AccessControl::resource_type`/`resource_action`? A container ID is a natural resource. `docker/container/exec` could require `resource: container/<id>:exec`. But containers are created at runtime — the resource set is dynamic. The `IdentityProvider` model in alknet-core is currently static (`PeerEntry` set). Dynamic resource ownership (who created this container, who can exec into it) needs a spec.
+
+### 4. Stdin closure semantics for raw carriage (design)
+
+The POC uses a zero-length stdin chunk as "client done sending input." bollard's `container_input.shutdown()` then closes the container's stdin so the process sees EOF. This works for the interactive case. But for a non-interactive exec with stdin (piping bytes in), the closure semantics need to be clearer: does the client send a zero-length chunk, or just close the write half of the duplex? The POC handles both (zero-length chunk breaks the loop; `ConnectionClosed` also breaks the loop), but the spec should pick one as the canonical "stdin done" signal.
+
+### 5. bollard version pinning (scoping)
+
+The POC uses the local checkout at 0.21.0. The real crate should depend on published 0.21 from crates.io (the dispatch POC pinned 0.18 — a 3-version jump). The `websocket` feature is optional; the `http` and `pipe` features are needed for socket/http connect. Confirm the published 0.21 has the same API surface as the checkout (it should — same version number).
+
+### 6. The normalization crate boundary (scoping)
+
+Where does `alknet-docker` end and the later normalization crate (`alknet-compute`?) begin? The conversation says alknet-docker is "more generalized" (thin wrapper over bollard) and the normalization layer (the `InstanceProvider` trait over docker/vast/runpod) comes later, in a separate crate. The POC validates the thin-wrapper side. The normalization crate is the fleet client that talks to multiple alknet-docker endpoints. This keeps alknet-docker single-host and bollard-specific; the normalization layer is transport-agnostic (it talks the call protocol, not bollard).
+
+---
+
+## Test Coverage
+
+```
+running 6 tests
+test frame_completed_carries_empty_payload ... ok
+test raw_chunk_round_trip_stdin_and_stdout ... ok
+test frame_round_trip_request_and_response ... ok
+test docker_attach_raw_round_trips_stdin_to_stdout ... ok
+test docker_logs_subscription_pumps_frames_and_completes ... ok
+test docker_exec_streams_output_and_exit_code ... ok
+
+test result: ok. 6 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 9.65s
+```
+
+The three docker-integration tests run against a live daemon (Docker Engine 29.2.1, API 1.53) using `alpine:3`. They pull the image if missing, create short-lived labeled containers, and clean up after. The three unit tests validate the frame/codec round-trip without docker.
+
+---
+
+## POC Structure
+
+```
+alknet-docker-poc/
+  Cargo.toml          — depends on bollard (path = "../bollard"), tokio, serde_json
+  src/
+    lib.rs            — module docs, the two-carriage model rationale
+    frame.rs          — EventEnvelope, FrameFramedReader/Writer (mirrors alknet-call wire.rs)
+    raw.rs            — Chunk, ChunkReader/Writer (1-byte stream-type + 4-byte length)
+    ops.rs            — DockerOps: drive_logs, drive_exec, drive_attach_raw
+  tests/
+    integration.rs    — 6 tests (3 docker-integration + 3 codec unit)
+```
+
+---
+
+## Key Code-to-Concept Mappings
+
+| POC concept | alknet-call equivalent | bollard equivalent |
+|---|---|---|
+| `EventEnvelope` (`frame.rs`) | `alknet_call::protocol::wire::EventEnvelope` | — |
+| `FrameFramedReader/Writer` | `alknet_call::protocol::wire::FrameFramedReader/Writer` | — |
+| `call.requested`/`responded`/`completed` | same event types | — |
+| `Chunk` stream_type 0/1/2 | — | `NewlineLogOutputDecoder` header byte (`read.rs:46`) |
+| `drive_logs` pump | `StreamingHandler` returning `Stream<ResponseEnvelope>` | `Docker::logs()` → `Stream<LogOutput>` |
+| `drive_exec` exit code | final `call.responded` before `call.completed` | `Docker::inspect_exec()` → `ExecInspectResponse.exit_code` |
+| `drive_attach_raw` raw handoff | `handle_stream` branch on `carriage: "raw"` (spec decision) | `Docker::attach_container()` → `AttachContainerResults { output, input }` |
+| `Carriage::Json`/`Raw` | (new field in `call.requested` payload) | — |
+
+---
+
+## References
+
+- bollard source (0.21.0): `/workspace/bollard` — `src/container.rs` (`attach_container` at :540, `attach_container_websocket` at :613, `LogOutput` at :96, `AttachContainerResults` at :80), `src/exec.rs` (`CreateExecOptions` at :28, `StartExecResults` enum at :99, `start_exec` at :225), `src/read.rs` (`NewlineLogOutputDecoder` at :32)
+- bollard examples: `/workspace/bollard/examples/attach_container.rs` (reliable attach + tty), `/workspace/bollard/examples/websocket_attach.rs` (websocket attach with reliability warning)
+- alknet-call wire format: `/workspace/@alkdev/alknet/crates/alknet-call/src/protocol/wire.rs` (EventEnvelope, FrameFramedReader/Writer — the POC's `frame.rs` mirrors this)
+- alknet-call dispatch: `/workspace/@alkdev/alknet/crates/alknet-call/src/protocol/dispatch.rs` (`handle_stream` at :295, `pump_stream` at :340 — the streaming pump the POC's `drive_logs`/`drive_exec` mirror)
+- alknet-call registry: `/workspace/@alkdev/alknet/crates/alknet-call/src/registry/registration.rs` (`StreamingHandler` at :20 — the handler shape for subscription ops)
+- dispatch POC: `/workspace/@alkdev/dispatch/src/docker.rs` (previous bollard 0.18 wrapping, opinionated for SSH key injection)
+- filesystem POC summary (structure reference): `/workspace/@alkdev/alknet/docs/research/alknet-filesystem/poc-summary.md`
+- SDD process: `/workspace/@alkdev/alknet/docs/sdd_process.md` (Phase 0 exploration → Phase 1 architecture)
+- System docs: `/workspace/system/README.md` (dev1 + ns528096 two-server setup, the fleet use case)

tasks/call/protocol/dispatch-streaming-branch.md

@@ -1,7 +1,7 @@
 ---
 id: call/protocol/dispatch-streaming-branch
 name: Wire Dispatcher::handle_stream streaming branch (Subscription → invoke_streaming → write each → call.completed)
-status: pending
+status: completed
 depends_on: [call/registry/invoke-streaming]
 scope: narrow
 risk: medium
@@ -171,4 +171,4 @@ task; aborting the connection cancels it).
 
 ## Summary
 
-> To be filled on completion
+> Added DispatchResult enum (Once(ResponseEnvelope) | Stream(ResponseStream)) and Dispatcher::dispatch() branching on op_type (looked up via registry.registration). handle_stream matches on DispatchResult — the branch is visible there (spec framing). Streaming pump writes each ResponseEnvelope → EventEnvelope frame; call.completed on natural end only when !last_was_error (Err is terminal, no call.completed after). deadline: None for streaming branch. Abort via Drop (no new code). Existing Query/Mutation path unchanged. Added 7 unit tests (dispatch branch, deadline clearing, pump frames, error terminal, query unchanged, unknown op, abort drops stream). 306 tests pass.

tasks/http/gateway/invoke-streaming.md

@@ -1,7 +1,7 @@
 ---
 id: http/gateway/invoke-streaming
 name: Implement GatewayDispatch::invoke_streaming() returning BoxStream<ResponseEnvelope>
-status: pending
+status: completed
 depends_on: [call/registry/invoke-streaming]
 scope: narrow
 risk: medium
@@ -127,4 +127,4 @@ don't duplicate the logic.
 
 ## Summary
 
-> To be filled on completion
+> Added GatewayDispatch::invoke_streaming() returning BoxStream<ResponseEnvelope>. Security axis provably identical to invoke() via shared build_root_context_inner(bounded: bool); extracted build_root_context_streaming for deadline: None (unbounded subscriptions). Calls OperationRegistry::invoke_streaming(). to_mcp untouched. Added 9 unit tests (all error paths + streaming dispatch + deadline: None verification). 243 tests pass.

tasks/http/server/subscribe-sse-streaming.md

@@ -1,7 +1,7 @@
 ---
 id: http/server/subscribe-sse-streaming
 name: Wire /subscribe handler to GatewayDispatch::invoke_streaming() and pipe BoxStream to SSE
-status: pending
+status: completed
 depends_on: [http/gateway/invoke-streaming]
 scope: narrow
 risk: medium
@@ -153,4 +153,4 @@ stream is dropped (not leaked) on disconnect.
 
 ## Summary
 
-> To be filled on completion
+> Replaced /subscribe one-event placeholder with real streaming path. subscribe_handler now calls GatewayDispatch::invoke_streaming() and pipes BoxStream to SSE via subscribe_stream_from_envelope_stream (StreamExt::map). Ok → data: frame, Err → event:error (terminal, stream ends after). Removed placeholder helpers (subscribe_stream_from_envelope, envelope_to_sse_stream). Kept subscribe_stream_internal_error for Internal ops (NOT_FOUND). Added 6 unit tests. Also fixed 2 pre-existing websocket subscription tests that expected INVALID_OPERATION_TYPE but now get call.responded (dispatch_requested routes Subscription via invoke_streaming). 247 tests pass.

tasks/review-streaming-impl.md

@@ -1,7 +1,7 @@
 ---
 id: review-streaming-impl
 name: Review ADR-049 streaming handler implementation for spec conformance and end-to-end correctness
-status: pending
+status: completed
 depends_on: [call/protocol/dispatch-streaming-branch, call/client/from-call-streaming-forwarding, http/gateway/invoke-streaming, http/server/subscribe-sse-streaming, http/adapters/from-openapi-sse-streaming]
 scope: broad
 risk: low
@@ -207,4 +207,4 @@ review.
 
 ## Summary
 
-> To be filled on completion
+> Reviewed ADR-049 streaming handler implementation across all 12 checklist points. All type surface, registry, builder, dispatch, from_call, gateway, /subscribe SSE, from_openapi SSE, ADR conformance, end-to-end correctness, pattern consistency, and test coverage items verified. 555 tests pass (306 call + 2 integration + 247 http), clippy clean, fmt clean. Fixed 2 pre-existing websocket subscription tests that expected INVALID_OPERATION_TYPE but now get call.responded (dispatch_requested routes Subscription via invoke_streaming). All 9 ADR-049 decisions implemented. Placeholders removed (subscribe_stream_from_envelope, envelope_to_sse_stream, stream_subscription). from_mcp unchanged (always HandlerKind::Once).