bxcore: a turn's speaker, SessionUpdated's turn, the session-state messages

Co-Authored-By: ornith-1.5-35b-a3b <agent@wntrmute.dev>

crates/bxcore/tests/fixtures/records/session_speaker.jsonl

@@ -0,0 +1,5 @@
+{"type":"session_start","time":"2026-09-27T09:00:00.000Z","session":"mm-r0000000000000000000000001","epoch":0,"slot":2,"baseline":"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f"}
+{"type":"user","time":"2026-09-27T09:00:01.000Z","content":"When is the launch?","speaker":"kyle"}
+{"type":"assistant","time":"2026-09-27T09:00:04.000Z","content":"On Thursday.","reasoning_content":null,"tool_calls":[]}
+{"type":"user","time":"2026-09-27T09:01:00.000Z","content":"And the review?"}
+{"type":"assistant","time":"2026-09-27T09:01:03.000Z","content":"On Friday.","reasoning_content":null,"tool_calls":[]}

crates/bxcore/tests/fixtures/wire/session_state.json

@@ -0,0 +1 @@
+{"v":1,"id":1,"final":true,"msg":{"kind":"session_state","body":{"session":"mm-r0000000000000000000000001"}}}

crates/bxcore/tests/fixtures/wire/session_state_reply.json

@@ -0,0 +1 @@
+{"v":1,"id":1,"final":true,"msg":{"kind":"session_state_reply","body":{"class":"private","untrusted":true}}}

crates/bxcore/tests/fixtures/wire/session_updated.json

@@ -1 +1 @@
-{"v":1,"id":1,"final":true,"msg":{"kind":"session_updated","body":{"session":"mm-r0000000000000000000000001"}}}
+{"v":1,"id":1,"final":true,"msg":{"kind":"session_updated","body":{"session":"mm-r0000000000000000000000001","turn":3}}}

crates/bxcore/tests/fixtures/wire/turn_speaker.json

@@ -0,0 +1 @@
+{"v":1,"id":3,"final":true,"msg":{"kind":"turn","body":{"session":"mm-r0000000000000000000000001","content":"What time is it?","resume":true,"speaker":"kyle"}}}

crates/bxcore/tests/memory_wire.rs

@@ -1,9 +1,11 @@
-//! The eight memory messages against byte-exact fixtures, each refusing an unknown key (M5a spec,
-//! section 7). Do not edit these or the fixtures.
+//! The memory messages against byte-exact fixtures, each refusing an unknown key: the eight of M5a
+//! (M5a spec, section 7) and the session-state question of M5c (M5c spec, section 7). Do not edit
+//! these or the fixtures.
 
 use bxcore::{
     CallId, DataClass, Empty, Envelope, MemoryAdmin, MemoryAdminReply, MemoryBlockReply,
-    MemoryCall, MemoryCommand, Message, Reindexed, SessionId, SessionUpdated, ToolRequest,
+    MemoryCall, MemoryCommand, Message, Reindexed, SessionId, SessionState, SessionStateReply,
+    SessionUpdated, ToolRequest,
 };
 
 const SESSION: &str = "mm-r0000000000000000000000001";
@@ -53,6 +55,7 @@ fn the_eight_messages() {
         1,
         Message::SessionUpdated(SessionUpdated {
             session: SessionId::new(SESSION).unwrap(),
+            turn: 3,
         }),
     );
     check(
@@ -96,6 +99,58 @@ fn the_eight_messages() {
     );
 }
 
+/// `turn` has no default: a `session_updated` without it, as a `loopd` from before M5c sent, is
+/// refused, never read as turn 0 (M5c spec, section 5).
+#[test]
+fn a_session_updated_without_turn_is_refused() {
+    let old = r#"{"v":1,"id":1,"final":true,"msg":{"kind":"session_updated","body":{"session":"mm-r0000000000000000000000001"}}}"#;
+    let error = serde_json::from_str::<Envelope>(old).unwrap_err();
+    assert!(
+        error.to_string().contains("missing field `turn`"),
+        "{error}"
+    );
+}
+
+/// `memoryd` asks `brokerd` for a session's state on `state.sock` (M5c spec, section 7).
+#[test]
+fn the_session_state_messages() {
+    check(
+        "session_state.json",
+        1,
+        Message::SessionState(SessionState {
+            session: SessionId::new(SESSION).unwrap(),
+        }),
+    );
+    check(
+        "session_state_reply.json",
+        1,
+        Message::SessionStateReply(SessionStateReply {
+            class: DataClass::Private,
+            untrusted: true,
+        }),
+    );
+}
+
+/// Neither field of the reply has a default: a reply without one is refused, never read as a
+/// clean or `public` session.
+#[test]
+fn a_session_state_reply_needs_both_fields() {
+    let text = fixture("session_state_reply.json");
+    for (field, without) in [
+        ("class", text.replacen(r#""class":"private","#, "", 1)),
+        ("untrusted", text.replacen(r#","untrusted":true"#, "", 1)),
+    ] {
+        assert_ne!(without, text, "{field}: the fixture holds the field");
+        let error = serde_json::from_str::<Envelope>(&without).unwrap_err();
+        assert!(
+            error
+                .to_string()
+                .contains(&format!("missing field `{field}`")),
+            "{field}: {error}"
+        );
+    }
+}
+
 #[test]
 fn every_command_has_its_name() {
     for (command, name) in [

crates/bxcore/tests/records.rs

@@ -235,6 +235,7 @@ fn session_log_records() {
         LogRecord::User {
             time: ts("2026-09-17T08:05:01.000Z"),
             content: "What is in /etc/hosts?".to_string(),
+            speaker: None,
         },
         LogRecord::Assistant {
             time: ts("2026-09-17T08:05:03.000Z"),
@@ -275,6 +276,45 @@ fn session_log_records() {
     check("session.jsonl", &want);
 }
 
+/// A user record holds its turn's speaker when the turn had one, written last; a record without
+/// one has the bytes it had before M5c, so a log written earlier reads as it is and is never
+/// rewritten (M5c spec, section 11).
+#[test]
+fn user_records_with_and_without_a_speaker() {
+    let want = [
+        LogRecord::SessionStart {
+            time: ts("2026-09-27T09:00:00.000Z"),
+            session: sid("mm-r0000000000000000000000001"),
+            epoch: Epoch(0),
+            slot: 2,
+            baseline: Hash32::from_hex(SEQ_HEX).unwrap(),
+        },
+        LogRecord::User {
+            time: ts("2026-09-27T09:00:01.000Z"),
+            content: "When is the launch?".to_string(),
+            speaker: Some("kyle".to_string()),
+        },
+        LogRecord::Assistant {
+            time: ts("2026-09-27T09:00:04.000Z"),
+            content: Some("On Thursday.".to_string()),
+            reasoning_content: None,
+            tool_calls: vec![],
+        },
+        LogRecord::User {
+            time: ts("2026-09-27T09:01:00.000Z"),
+            content: "And the review?".to_string(),
+            speaker: None,
+        },
+        LogRecord::Assistant {
+            time: ts("2026-09-27T09:01:03.000Z"),
+            content: Some("On Friday.".to_string()),
+            reasoning_content: None,
+            tool_calls: vec![],
+        },
+    ];
+    check("session_speaker.jsonl", &want);
+}
+
 #[test]
 fn unknown_fields_and_types_are_rejected() {
     let user = r#"{"type":"user","time":"2026-09-17T08:05:01.000Z","content":"hi"}"#;

crates/bxcore/tests/strict.rs

@@ -92,6 +92,10 @@ fn envelopes_reject_unknown_keys_at_every_depth() {
         "error_no_such_approval.json",
         "turn_event_approval_pending.json",
         "turn_event_tool_denied.json",
+        "turn_speaker.json",
+        "session_updated.json",
+        "session_state.json",
+        "session_state_reply.json",
     ] {
         // Envelope, msg and body: three objects. Some bodies hold more: turn_done a usage
         // object, approval_list one item, approve_result an outcome, grants_report two problems.
@@ -142,6 +146,16 @@ fn usage_log_records_reject_unknown_keys_at_every_depth() {
     assert_eq!(tried, 8);
 }
 
+#[test]
+fn speaker_log_records_reject_unknown_keys_at_every_depth() {
+    let mut tried = 0;
+    for (i, line) in fixture("records/session_speaker.jsonl").lines().enumerate() {
+        tried += check::<LogRecord>(&format!("session_speaker.jsonl:{}", i + 1), line);
+    }
+    // Five records, none holding another object.
+    assert_eq!(tried, 5);
+}
+
 #[test]
 fn grants_reject_unknown_keys_at_every_depth() {
     let grant: Grant = toml::from_str(&fixture("grant/full.toml")).unwrap();

crates/bxcore/tests/turn_wire.rs

@@ -46,16 +46,46 @@ fn usage() -> Usage {
     }
 }
 
+/// A turn without a speaker has the bytes it had before M5c, and a frame without `speaker` reads
+/// as `None`: a turn with no speaker is never synced (M5c spec, section 4).
 #[test]
 fn turn() {
     let body = Turn {
         session: SessionId::new("chat-1789700000-42").unwrap(),
         content: "What time is it?".to_string(),
         resume: false,
+        speaker: None,
     };
     check("turn.json", env(3, true, Message::Turn(body)));
 }
 
+/// The speaker is written last, when there is one (M5c spec, section 11).
+#[test]
+fn turn_with_a_speaker() {
+    let body = Turn {
+        session: SessionId::new("mm-r0000000000000000000000001").unwrap(),
+        content: "What time is it?".to_string(),
+        resume: true,
+        speaker: Some("kyle".to_string()),
+    };
+    check("turn_speaker.json", env(3, true, Message::Turn(body)));
+}
+
+/// `bxcore` does not check a speaker's name: `memoryd` checks it against Honcho's pattern (M5c
+/// spec, section 3). A Mattermost username with a `.` is carried as it is.
+#[test]
+fn a_speaker_is_carried_as_it_is() {
+    let body = Turn {
+        session: SessionId::new("mm-r0000000000000000000000001").unwrap(),
+        content: "hi".to_string(),
+        resume: false,
+        speaker: Some("first.last".to_string()),
+    };
+    let text = serde_json::to_string(&body).unwrap();
+    assert!(text.ends_with(r#","speaker":"first.last"}"#), "{text}");
+    assert_eq!(serde_json::from_str::<Turn>(&text).unwrap(), body);
+}
+
 #[test]
 fn turn_events() {
     check(
@@ -262,6 +292,7 @@ fn usage_records() {
         LogRecord::User {
             time: Timestamp::parse("2026-09-18T08:05:01.000Z").unwrap(),
             content: "What time is it?".to_string(),
+            speaker: None,
         },
         LogRecord::Assistant {
             time: Timestamp::parse("2026-09-18T08:05:03.000Z").unwrap(),