feat: regenerate covers interjection turns (T73.2)

Phase 2 T44 deferred interjection regenerate — when the original turn
group included a follow-on interjection beat we left it untouched. Now
regenerate redoes BOTH halves:

- Detect a sibling interjection by looking up assistant_turn events
  pinned to the same user_turn_id with `interjection_of` set.
- After streaming the new primary, run `detect_interjection` against
  the new primary text.
- If True: stream a new interjection from the silent witness, append
  with `interjection_of=<new primary speaker_id>`, supersede the
  original interjection, and re-run memory + state-update for the new
  beat.
- If False: supersede the original interjection without a replacement
  (back-pointer goes to the new primary so the row stays consistently
  hidden).

Also broadcast a `turn_html_replace` event for the new interjection so
the front-end can swap the prior interjection node in place (mirrors
T73.1's primary swap).

Tests:
- `test_regenerate_with_interjection_redoes_both_turns`: classifier
  returns True; assert two new assistant_turns land for the same
  user_turn, second carries `interjection_of`, originals superseded.
- `test_regenerate_drops_interjection_when_classifier_returns_false`:
  classifier returns False; assert one new assistant_turn (primary
  only) and the original interjection is superseded with no
  replacement.

`interjection_of` carries the primary's *speaker_id* (matching the
existing convention in chat/web/turns.py) rather than the event_id.

chat/services/regenerate.py

@@ -73,6 +73,7 @@ from sqlite3 import Connection
 
 from chat.config import Settings
 from chat.eventlog.log import append_and_apply, append_event
+from chat.services.interjection import detect_interjection
 from chat.services.memory_write import record_turn_memory_for_present
 from chat.services.multi_state_update import compute_state_updates_for_present
 from chat.services.prompt import assemble_narrative_prompt
@@ -131,6 +132,33 @@ async def regenerate_assistant_turn(
         raise ValueError("assistant_turn event not found")
     original_assistant_payload = json.loads(row[0])
     original_user_turn_id = original_assistant_payload.get("user_turn_id")
+
+    # 1a. Look up any sibling interjection beat in the same turn group
+    # (T73.2). The original group is (primary + optional interjection),
+    # both pinned to the same ``user_turn_id``. The interjection has a
+    # populated ``interjection_of`` field in its payload — its speaker is
+    # the silent witness (the bot that wasn't the primary addressee).
+    # Filter on ``superseded_by IS NULL`` so prior regenerates of this
+    # group don't reappear as siblings.
+    original_interjection_event_id: int | None = None
+    original_interjection_payload: dict | None = None
+    if original_user_turn_id is not None:
+        sibling_cur = conn.execute(
+            "SELECT id, payload_json FROM event_log "
+            "WHERE kind = 'assistant_turn' "
+            "  AND id != ? "
+            "  AND superseded_by IS NULL",
+            (original_assistant_event_id,),
+        )
+        for sib_id, sib_payload_json in sibling_cur.fetchall():
+            sib_payload = json.loads(sib_payload_json)
+            if sib_payload.get("user_turn_id") != original_user_turn_id:
+                continue
+            if not sib_payload.get("interjection_of"):
+                continue
+            original_interjection_event_id = sib_id
+            original_interjection_payload = sib_payload
+            break
     # Phase 2 v2 regenerates only the addressee turn — preserve whichever
     # bot the original turn was attributed to, falling back to the host
     # for legacy rows that pre-date multi-entity support.
@@ -361,6 +389,234 @@ async def regenerate_assistant_turn(
             },
         )
 
+    # 9. Interjection regenerate branch (T73.2). When the original
+    # assistant_turn group included a follow-on interjection beat we need
+    # to revisit that beat against the regenerated primary. Three outcomes:
+    #
+    #   - No original interjection: nothing to do; we already short-circuit
+    #     above by leaving ``original_interjection_event_id`` as None.
+    #   - Original interjection + classifier returns True: stream a fresh
+    #     interjection from the silent witness, append it (with
+    #     ``interjection_of`` linking to the new primary speaker), and
+    #     supersede the original interjection's row. Also re-run memory
+    #     + state-update so the second beat moves edges + writes memories.
+    #   - Original interjection + classifier returns False: supersede the
+    #     original interjection without appending a replacement. The
+    #     regenerated group becomes "primary only" because the new primary
+    #     no longer warrants a follow-on. No memory / state work needed
+    #     for the absent beat.
+    #
+    # ``superseded_by`` on the original interjection's row points at the
+    # *new primary* in the no-replacement case (rather than NULL or a
+    # nonexistent id) so the row is consistently hidden by the standard
+    # ``superseded_by IS NULL`` timeline filter and the back-pointer
+    # leads somewhere meaningful for an "originally said …" affordance.
+    if original_interjection_event_id is not None and guest_bot is not None:
+        # Identify the silent witness from the original interjection's
+        # speaker_id (which is the bot that interjected last time). When
+        # we regenerate we keep the *same pair of present entities*, so
+        # the silent witness is whichever bot isn't the new primary
+        # speaker — derive it from present rather than reusing the prior
+        # speaker_id verbatim, in case the regenerated primary swapped
+        # who held the floor.
+        if speaker_bot_id == host_bot_id:
+            silent_witness = guest_bot
+        else:
+            silent_witness = host_bot
+        silent_witness_id = silent_witness.get("id")
+
+        edge_w_to_addr = get_edge(conn, silent_witness_id, speaker_bot_id) or {
+            "affinity": 50,
+            "trust": 50,
+            "summary": "",
+        }
+        edge_w_to_you = get_edge(conn, silent_witness_id, "you") or {
+            "affinity": 50,
+            "trust": 50,
+            "summary": "",
+        }
+
+        decision = await detect_interjection(
+            client,
+            classifier_model=settings.classifier_model,
+            addressee_name=speaker_bot.get("name", "bot"),
+            addressee_just_said=new_text,
+            silent_witness_name=silent_witness.get("name", "bot"),
+            silent_witness_persona=silent_witness.get("persona") or "",
+            silent_witness_edge_to_addressee=edge_w_to_addr,
+            silent_witness_edge_to_you=edge_w_to_you,
+            you_just_said=prose_for_prompt or "",
+            timeout_s=settings.classifier_timeout_s,
+        )
+
+        if decision.should_interject:
+            # Re-read recent so the just-appended primary is in the prompt.
+            interject_cur = conn.execute(
+                "SELECT id, kind, payload_json FROM event_log "
+                "WHERE kind IN ('user_turn', 'user_turn_edit', 'assistant_turn') "
+                "  AND superseded_by IS NULL AND hidden = 0 "
+                "ORDER BY id DESC LIMIT 20",
+            )
+            interject_rows = list(reversed(interject_cur.fetchall()))
+            interject_recent: list[dict] = []
+            for _eid, kind, payload_json in interject_rows:
+                p = json.loads(payload_json)
+                if p.get("chat_id") != chat_id:
+                    continue
+                if kind in ("user_turn", "user_turn_edit"):
+                    interject_recent.append(
+                        {"speaker": you_name, "text": p.get("prose", "")}
+                    )
+                else:
+                    spk = p.get("speaker_id", "bot")
+                    if spk == host_bot_id:
+                        spk_name = host_bot.get("name", "bot")
+                    elif spk == guest_bot.get("id"):
+                        spk_name = guest_bot.get("name", "bot")
+                    else:
+                        spk_name = "bot"
+                    interject_recent.append(
+                        {"speaker": spk_name, "text": p.get("text", "")}
+                    )
+            if interject_recent and interject_recent[-1].get("speaker") == you_name:
+                interject_recent = interject_recent[:-1]
+
+            interject_messages = assemble_narrative_prompt(
+                conn,
+                chat_id=chat_id,
+                speaker_bot_id=silent_witness_id,
+                addressee=speaker_bot_id,
+                user_turn_prose=prose_for_prompt or None,
+                recent_dialogue=interject_recent,
+                budget_soft=settings.narrative_budget_soft,
+                budget_hard=settings.narrative_budget_hard,
+                guest_id=guest_bot_id,
+            )
+
+            interject_accumulated: list[str] = []
+            async for chunk in client.stream(
+                interject_messages,
+                model=settings.narrative_model,
+                max_tokens=settings.narrative_max_tokens,
+                temperature=settings.narrative_temperature,
+            ):
+                interject_accumulated.append(chunk)
+                await publish(
+                    chat_id,
+                    {
+                        "event": "token",
+                        "text": chunk,
+                        "speaker_id": silent_witness_id,
+                    },
+                )
+            interject_text = "".join(interject_accumulated)
+
+            new_interjection_event_id = append_event(
+                conn,
+                kind="assistant_turn",
+                payload={
+                    "chat_id": chat_id,
+                    "speaker_id": silent_witness_id,
+                    "text": interject_text,
+                    "truncated": False,
+                    "user_turn_id": (
+                        new_user_event_id
+                        if new_user_event_id is not None
+                        else original_user_turn_id
+                    ),
+                    "regenerated_from": original_interjection_event_id,
+                    "interjection_of": speaker_bot_id,
+                },
+            )
+
+            # Supersede the original interjection by the new one.
+            conn.execute(
+                "UPDATE event_log SET superseded_by = ? WHERE id = ?",
+                (new_interjection_event_id, original_interjection_event_id),
+            )
+
+            # Broadcast a replace event so connected tabs swap the prior
+            # interjection node in-place (mirrors T73.1's primary swap).
+            interject_html = render_turn_html(
+                silent_witness.get("name", "bot"), interject_text, role="bot"
+            )
+            await publish(
+                chat_id,
+                {
+                    "event": "turn_html_replace",
+                    "data": interject_html,
+                    "turn_id": new_interjection_event_id,
+                    "supersedes_id": original_interjection_event_id,
+                },
+            )
+
+            # Memory write for the new interjection beat (one event per
+            # present witness).
+            record_turn_memory_for_present(
+                conn,
+                chat_id=chat_id,
+                host_bot_id=host_bot_id,
+                guest_bot_id=guest_bot_id,
+                narrative_text=interject_text,
+                scene_id=scene["id"] if scene else None,
+                chat_clock_at=chat.get("time"),
+            )
+
+            # Re-run the multi-pair state-update with the post-interjection
+            # dialogue tail so deltas land on the post-primary baseline.
+            recent_post_interject = recent_for_update + [
+                {
+                    "speaker": silent_witness.get("name", "bot"),
+                    "text": interject_text,
+                }
+            ]
+            prior_edges_post: dict[tuple[str, str], dict] = {}
+            for src in present_ids:
+                for tgt in present_ids:
+                    if src == tgt:
+                        continue
+                    edge = get_edge(conn, src, tgt) or {
+                        "affinity": 50,
+                        "trust": 50,
+                        "summary": "",
+                    }
+                    prior_edges_post[(src, tgt)] = edge
+
+            state_updates_post = await compute_state_updates_for_present(
+                client,
+                classifier_model=settings.classifier_model,
+                present_ids=present_ids,
+                present_names=present_names,
+                personas=personas,
+                prior_edges=prior_edges_post,
+                recent_dialogue=recent_post_interject,
+                timeout_s=settings.classifier_timeout_s,
+            )
+            for src_id, tgt_id, update in state_updates_post:
+                append_and_apply(
+                    conn,
+                    kind="edge_update",
+                    payload={
+                        "source_id": src_id,
+                        "target_id": tgt_id,
+                        "chat_id": chat_id,
+                        "affinity_delta": update.affinity_delta,
+                        "trust_delta": update.trust_delta,
+                        "knowledge_facts": update.knowledge_facts,
+                        "last_interaction_at": last_at,
+                        "last_interaction_chat_id": chat_id,
+                    },
+                )
+        else:
+            # Classifier said "no follow-on this time" — supersede the
+            # original interjection without a replacement. Point the
+            # back-pointer at the new primary so the row is consistently
+            # hidden by the standard timeline filter.
+            conn.execute(
+                "UPDATE event_log SET superseded_by = ? WHERE id = ?",
+                (new_assistant_event_id, original_interjection_event_id),
+            )
+
     return new_text
 
 

tests/test_regenerate.py

@@ -273,6 +273,114 @@ def test_regenerate_404_when_assistant_turn_missing(client, tmp_path):
         app.dependency_overrides.clear()
 
 
+def _seed_with_interjection_group(db_path):
+    """Seed a multi-entity scene with a (primary + interjection) group.
+
+    Returns ``(user_turn_id, primary_at_id, interjection_at_id)``.
+
+    The primary speaker is the host (bot_a); the silent witness who
+    interjected is the guest (bot_b). Mirrors the convention in
+    chat/web/turns.py — both assistant_turns share the same
+    ``user_turn_id`` and the interjection's payload carries
+    ``interjection_of=<primary speaker_id>``.
+    """
+    with open_db(db_path) as conn:
+        for bot_id, name, persona in (
+            ("bot_a", "BotA", "thoughtful"),
+            ("bot_b", "BotB", "loud"),
+        ):
+            append_event(
+                conn,
+                kind="bot_authored",
+                payload={
+                    "id": bot_id,
+                    "name": name,
+                    "persona": persona,
+                    "voice_samples": [],
+                    "traits": [],
+                    "backstory": "",
+                    "initial_relationship_to_you": "",
+                    "kickoff_prose": "",
+                },
+            )
+        append_event(
+            conn,
+            kind="chat_created",
+            payload={
+                "id": "chat_multi",
+                "host_bot_id": "bot_a",
+                "guest_bot_id": "bot_b",
+                "initial_time": "2026-04-26T20:00:00+00:00",
+                "narrative_anchor": "Day 1",
+                "weather": "",
+            },
+        )
+        for src, tgt in (
+            ("bot_a", "you"),
+            ("you", "bot_a"),
+            ("bot_b", "you"),
+            ("you", "bot_b"),
+            ("bot_a", "bot_b"),
+            ("bot_b", "bot_a"),
+        ):
+            append_event(
+                conn,
+                kind="edge_update",
+                payload={
+                    "source_id": src,
+                    "target_id": tgt,
+                    "chat_id": "chat_multi",
+                },
+            )
+        for entity_id in ("you", "bot_a", "bot_b"):
+            append_event(
+                conn,
+                kind="activity_change",
+                payload={
+                    "entity_id": entity_id,
+                    "posture": "sitting",
+                    "action": {"verb": "talking"},
+                    "attention": "",
+                    "holding": [],
+                    "status": {},
+                },
+            )
+        ut_id = append_event(
+            conn,
+            kind="user_turn",
+            payload={
+                "chat_id": "chat_multi",
+                "prose": "hello",
+                "segments": [],
+            },
+        )
+        primary_id = append_event(
+            conn,
+            kind="assistant_turn",
+            payload={
+                "chat_id": "chat_multi",
+                "speaker_id": "bot_a",
+                "text": "Original primary.",
+                "truncated": False,
+                "user_turn_id": ut_id,
+            },
+        )
+        interjection_id = append_event(
+            conn,
+            kind="assistant_turn",
+            payload={
+                "chat_id": "chat_multi",
+                "speaker_id": "bot_b",
+                "text": "Original interjection!",
+                "truncated": False,
+                "user_turn_id": ut_id,
+                "interjection_of": "bot_a",
+            },
+        )
+        project(conn)
+        return ut_id, primary_id, interjection_id
+
+
 def test_regenerate_broadcasts_turn_html_over_sse(
     tmp_path, monkeypatch
 ):
@@ -353,3 +461,204 @@ def test_regenerate_broadcasts_turn_html_over_sse(
     # Sanity: every publish targeted this chat.
     for cid, _ev in published:
         assert cid == "chat_bot_a"
+
+
+def test_regenerate_with_interjection_redoes_both_turns(tmp_path, monkeypatch):
+    """T73.2: when the original turn group included an interjection, both
+    the primary and the interjection are regenerated.
+
+    Setup: 3-entity scene (host BotA + guest BotB + you) with a prior
+    (primary by BotA + interjection by BotB) group. Mock the
+    interjection classifier to return ``should_interject=True`` so the
+    follow-on regenerates too.
+
+    Assert: 2 new assistant_turns exist for the same user_turn_id, the
+    second carrying ``interjection_of`` pointing at the new primary's
+    speaker_id. Both originals are superseded.
+    """
+    import asyncio
+
+    from chat.config import Settings
+    from chat.db.migrate import apply_migrations
+    from chat.services import regenerate as regenerate_module
+    from chat.services.interjection import InterjectionDecision
+    from chat.services.regenerate import regenerate_assistant_turn
+
+    db_path = tmp_path / "test.db"
+    cfg = tmp_path / "config.toml"
+    cfg.write_text('featherless_api_key = "test"\n')
+    monkeypatch.setenv("CHAT_CONFIG_PATH", str(cfg))
+    monkeypatch.setenv("CHAT_DB_PATH", str(db_path))
+    apply_migrations(db_path)
+
+    ut_id, primary_id, interjection_id = _seed_with_interjection_group(db_path)
+
+    # Stub detect_interjection so the classifier "fires" with new prose.
+    async def _stub_should_interject(*_args, **_kwargs):
+        return InterjectionDecision(should_interject=True, reason="fired")
+
+    monkeypatch.setattr(
+        regenerate_module, "detect_interjection", _stub_should_interject
+    )
+
+    # Canned queue:
+    #   1. New primary narrative stream.
+    #   2-7. Six state-update classifier calls (one per directed pair
+    #        across host/you/guest = 6 pairs) for the primary pass.
+    #   8.   New interjection narrative stream.
+    #   9-14. Six state-update classifier calls for the post-interjection
+    #         pass.
+    state_canned = json.dumps(
+        {"affinity_delta": 0, "trust_delta": 0, "knowledge_facts": []}
+    )
+    canned: list[str] = []
+    canned.append("New primary text.")
+    canned.extend([state_canned] * 6)
+    canned.append("New interjection text!")
+    canned.extend([state_canned] * 6)
+    mock_client = MockLLMClient(canned=list(canned))
+
+    settings = Settings(featherless_api_key="test")
+
+    with open_db(db_path) as conn:
+        new_text = asyncio.run(
+            regenerate_assistant_turn(
+                conn,
+                mock_client,
+                settings=settings,
+                chat_id="chat_multi",
+                original_assistant_event_id=primary_id,
+            )
+        )
+        assert new_text == "New primary text."
+
+        # Both originals are superseded.
+        primary_super = conn.execute(
+            "SELECT superseded_by FROM event_log WHERE id = ?", (primary_id,)
+        ).fetchone()[0]
+        interjection_super = conn.execute(
+            "SELECT superseded_by FROM event_log WHERE id = ?",
+            (interjection_id,),
+        ).fetchone()[0]
+        assert primary_super is not None
+        assert interjection_super is not None
+
+        # Two NEW assistant_turn events exist (the regenerated primary
+        # and the regenerated interjection), both pinned to the same
+        # user_turn_id as the originals.
+        cur = conn.execute(
+            "SELECT id, payload_json FROM event_log "
+            "WHERE kind = 'assistant_turn' AND id NOT IN (?, ?) "
+            "ORDER BY id",
+            (primary_id, interjection_id),
+        ).fetchall()
+        assert len(cur) == 2
+        new_primary_id, new_primary_payload_json = cur[0]
+        new_interjection_id, new_interjection_payload_json = cur[1]
+        new_primary_payload = json.loads(new_primary_payload_json)
+        new_interjection_payload = json.loads(new_interjection_payload_json)
+
+        assert new_primary_payload["text"] == "New primary text."
+        assert new_primary_payload["speaker_id"] == "bot_a"
+        assert new_primary_payload["user_turn_id"] == ut_id
+        assert new_primary_payload["regenerated_from"] == primary_id
+        assert "interjection_of" not in new_primary_payload
+
+        assert new_interjection_payload["text"] == "New interjection text!"
+        assert new_interjection_payload["speaker_id"] == "bot_b"
+        assert new_interjection_payload["user_turn_id"] == ut_id
+        assert new_interjection_payload["regenerated_from"] == interjection_id
+        # interjection_of links to the new primary's speaker (matches
+        # the existing convention in chat/web/turns.py).
+        assert new_interjection_payload["interjection_of"] == "bot_a"
+
+        # The originals' supersede pointers reach the new ones.
+        assert primary_super == new_primary_id
+        assert interjection_super == new_interjection_id
+
+
+def test_regenerate_drops_interjection_when_classifier_returns_false(
+    tmp_path, monkeypatch
+):
+    """T73.2: when the original group included an interjection but the
+    classifier returns False this time, the new group is primary-only.
+
+    The original interjection is still superseded (we don't leave it
+    visible in the timeline alongside a regenerated primary it no longer
+    follows from), but no replacement assistant_turn is appended.
+    """
+    import asyncio
+
+    from chat.config import Settings
+    from chat.db.migrate import apply_migrations
+    from chat.services import regenerate as regenerate_module
+    from chat.services.interjection import InterjectionDecision
+    from chat.services.regenerate import regenerate_assistant_turn
+
+    db_path = tmp_path / "test.db"
+    cfg = tmp_path / "config.toml"
+    cfg.write_text('featherless_api_key = "test"\n')
+    monkeypatch.setenv("CHAT_CONFIG_PATH", str(cfg))
+    monkeypatch.setenv("CHAT_DB_PATH", str(db_path))
+    apply_migrations(db_path)
+
+    ut_id, primary_id, interjection_id = _seed_with_interjection_group(db_path)
+
+    async def _stub_no_interject(*_args, **_kwargs):
+        return InterjectionDecision(
+            should_interject=False, reason="quiet"
+        )
+
+    monkeypatch.setattr(
+        regenerate_module, "detect_interjection", _stub_no_interject
+    )
+
+    # Canned queue: primary narrative + 6 state-update calls. No
+    # interjection stream because the classifier short-circuits.
+    state_canned = json.dumps(
+        {"affinity_delta": 0, "trust_delta": 0, "knowledge_facts": []}
+    )
+    canned: list[str] = ["New primary text."] + [state_canned] * 6
+    mock_client = MockLLMClient(canned=list(canned))
+
+    settings = Settings(featherless_api_key="test")
+
+    with open_db(db_path) as conn:
+        new_text = asyncio.run(
+            regenerate_assistant_turn(
+                conn,
+                mock_client,
+                settings=settings,
+                chat_id="chat_multi",
+                original_assistant_event_id=primary_id,
+            )
+        )
+        assert new_text == "New primary text."
+
+        # Original primary superseded by the new primary.
+        primary_super = conn.execute(
+            "SELECT superseded_by FROM event_log WHERE id = ?", (primary_id,)
+        ).fetchone()[0]
+        # Original interjection ALSO superseded — we don't leave a
+        # dangling beat attached to a regenerated primary that no longer
+        # warrants a follow-on. Back-pointer goes to the new primary.
+        interjection_super = conn.execute(
+            "SELECT superseded_by FROM event_log WHERE id = ?",
+            (interjection_id,),
+        ).fetchone()[0]
+        assert primary_super is not None
+        assert interjection_super is not None
+        assert interjection_super == primary_super  # both point at new primary
+
+        # Exactly ONE new assistant_turn — the primary; no replacement
+        # interjection.
+        cur = conn.execute(
+            "SELECT payload_json FROM event_log "
+            "WHERE kind = 'assistant_turn' AND id NOT IN (?, ?) "
+            "AND superseded_by IS NULL",
+            (primary_id, interjection_id),
+        ).fetchall()
+        assert len(cur) == 1
+        new_primary_payload = json.loads(cur[0][0])
+        assert new_primary_payload["text"] == "New primary text."
+        assert "interjection_of" not in new_primary_payload