fix(runtime): isolate nested invocation ownership

scripts/validate_runtime_wave1.sh

@@ -9,6 +9,7 @@ export ODYSSEUS_DATA_DIR="${ODYSSEUS_DATA_DIR:-/tmp/odysseus-runtime-decompositi
 exec "${ODYSSEUS_TEST_PYTHON:-python3}" -m pytest -q -p no:cacheprovider \
   tests/test_runtime_evidence_contract.py tests/test_agent_evidence.py \
   tests/test_completion_boundary.py \
+  tests/test_nested_invocation_ownership.py \
   tests/test_agent_evidence_loop.py tests/test_agent_render_ownership.py \
   tests/test_agent_runs_terminal_order.py tests/test_agent_loop.py \
   tests/test_tool_task_cancelled_on_disconnect.py tests/test_turn_contract.py \

src/agent_loop.py

@@ -84,6 +84,7 @@ from src.tool_types import ToolBlock
 from src.turn_contract import selected_tools_for_request, with_turn_contract
 from src.agent_runtime.journal import propose_action, execute_action
 from src.agent_runtime.completion import with_completion_gate
+from src.teacher_escalation import with_teacher_takeover, request_teacher_takeover
 from src.tool_utils import _truncate, get_mcp_manager
 from src.agent_tools import (
     parse_tool_blocks,
@@ -20326,6 +20327,7 @@ def _blocks_before_inference(turn_contract) -> bool:
 
 
 @with_turn_contract
+@with_teacher_takeover
 @with_completion_gate
 async def stream_agent_loop(
     endpoint_url: str,
@@ -20368,6 +20370,7 @@ async def stream_agent_loop(
     thinking_mode: Optional[str] = None,
     suppress_skills: bool = False,
     reasoning_effort: Optional[str] = None,
+    _parent_run_id: Optional[str] = None,
 ) -> AsyncGenerator[str, None]:
     """Streaming agent loop generator.
 
@@ -37239,29 +37242,25 @@ async def stream_agent_loop(
     )
     yield f"data: {json.dumps({'type': 'metrics', 'data': metrics})}\n\n"
 
-    # Teacher-escalation: inline takeover visible in the chat stream.
+    # Queue the existing teacher hook. The outer adapter executes it only
-    # The student just finished; if Tier 1 flags failure, the teacher
+    # after this invocation's completion gate and action context have closed.
-    # gets a turn (with its own tool calls forwarded to the user) and
-    # a skill is saved ONLY if the teacher actually succeeds. Skipped
-    # when we ARE the teacher to avoid recursion.
     if not _is_teacher_run and not guide_only and not _awaiting_user:
-        try:
+        request_teacher_takeover(
-            from src.teacher_escalation import run_teacher_inline
+            student_endpoint_url=endpoint_url,
-            async for evt in run_teacher_inline(
+            student_messages=messages,
-                student_endpoint_url=endpoint_url,
+            student_tool_events=tool_events,
-                student_messages=messages,
+            student_reply=full_response,
-                student_tool_events=tool_events,
+            owner=owner,
-                student_reply=full_response,
+            session_id=session_id,
-                owner=owner,
+            workspace=workspace,
-                session_id=session_id,
+            disabled_tools=disabled_tools,
-                workspace=workspace,
+            tool_policy=tool_policy,
-                disabled_tools=disabled_tools,
+            active_document=active_document,
-                tool_policy=tool_policy,
+            active_email=active_email,
-                active_document=active_document,
+            turn_contract=turn_contract,
-                active_email=active_email,
+            external_untrusted_context_seen=run_security.external_untrusted_context_seen,
-            ):
+            client_runtime_context=client_runtime_context,
-                yield evt
+            plan_mode=plan_mode,
-        except Exception as _esc_err:
+        )
-            logger.warning(f"teacher escalation hook failed: {_esc_err}", exc_info=True)
 
     yield "data: [DONE]\n\n"

src/agent_runtime/completion.py

@@ -181,8 +181,9 @@ def with_completion_gate(func):
         trusted_workspace = vet_workspace(bound.get('workspace')) if bound.get('workspace') else ''
         requirements = replace(requirements, workspace_root=trusted_workspace or '')
         parent = current_journal()
-        journal = parent if parent is not None and parent.workspace == requirements.workspace_root else ActionJournal(
+        journal = ActionJournal(
-            workspace=requirements.workspace_root, observed_artifacts=requirements.required_artifacts)
+            workspace=requirements.workspace_root, observed_artifacts=requirements.required_artifacts,
+            parent_run_id=bound.get('_parent_run_id') or (parent.run_id if parent is not None else None))
         answer_events: list[dict] = []
         metrics_events: list[dict] = []
         answer = ''
@@ -308,7 +309,8 @@ def with_completion_gate(func):
             for event in metrics_events:
                 metadata = event.setdefault('data', {})
                 metadata.update(completion_decision=decision.to_dict(), evidence_events=ledger.to_list(),
-                                action_receipts=journal.to_list(), completion_requirements=requirements.to_dict())
+                                action_receipts=journal.to_list(), completion_requirements=requirements.to_dict(),
+                                run_id=journal.run_id, parent_run_id=journal.parent_run_id)
                 metadata['completion_gate'] = {
                     'buffer_seconds': released_at - first_answer_at if first_answer_at is not None else 0,
                     'first_visible_answer_seconds': released_at - started,

src/agent_runtime/journal.py

@@ -66,6 +66,7 @@ class ActionJournal:
     actions: list[ActionReceipt] = field(default_factory=list)
     workspace: str = ''
     observed_artifacts: tuple[str, ...] = ()
+    parent_run_id: str | None = None
 
     def capture_versions(self, action: ActionReceipt) -> None:
         if self.workspace:
@@ -111,9 +112,11 @@ _ACTION: ContextVar[ActionReceipt | None] = ContextVar('runtime_current_action',
 @contextmanager
 def bind_journal(journal: ActionJournal):
     token = _JOURNAL.set(journal)
+    action_token = _ACTION.set(None)
     try:
         yield journal
     finally:
+        _ACTION.reset(action_token)
         _JOURNAL.reset(token)
 
 

src/teacher_escalation.py

@@ -24,6 +24,10 @@ itself wasn't confident about.
 from __future__ import annotations
 
 import asyncio
+from contextlib import aclosing
+from contextvars import ContextVar
+from copy import deepcopy
+from functools import wraps
 import logging
 import re
 from typing import Any, Dict, List, Optional, Tuple
@@ -32,6 +36,58 @@ from urllib.parse import urlparse
 logger = logging.getLogger(__name__)
 
 
+_TAKEOVER: ContextVar[dict | None] = ContextVar('teacher_takeover_request', default=None)
+
+
+def request_teacher_takeover(**parameters):
+    """Record a finished student's handoff; execution waits for its gate to close."""
+    from src.agent_runtime.journal import current_journal
+    request = _TAKEOVER.get()
+    if request is not None:
+        journal = current_journal()
+        request.update(parameters, parent_run_id=journal.run_id if journal is not None else None)
+
+
+def with_teacher_takeover(func):
+    """Orchestrate gated invocations and own the single outer stream terminator."""
+    @wraps(func)
+    async def wrapped(*args, **kwargs):
+        request = {}
+        token = _TAKEOVER.set(request)
+        done = False
+        failed = False
+        try:
+            async with aclosing(func(*args, **kwargs)) as stream:
+                async for chunk in stream:
+                    if chunk.strip() == 'data: [DONE]':
+                        done = True
+                        continue
+                    failed |= chunk.startswith('event: error')
+                    yield chunk
+            # The parent generator and gate have both unwound. Child control
+            # events now belong only to the child, never to the parent gate.
+            if request and not failed:
+                try:
+                    async with aclosing(run_teacher_inline(**request)) as stream:
+                        async for chunk in stream:
+                            if chunk.strip() == 'data: [DONE]':
+                                continue
+                            failed |= chunk.startswith('event: error')
+                            yield chunk
+                except Exception as exc:
+                    logger.warning('teacher escalation hook failed: %s', exc, exc_info=True)
+                    if not failed:
+                        import json
+                        yield 'data: ' + json.dumps({'type': 'escalation_failed', 'reason': str(exc),
+                                                    'teacher': True}) + '\n\n'
+            if done and not failed:
+                yield 'data: [DONE]\n\n'
+        finally:
+            _TAKEOVER.reset(token)
+
+    return wrapped
+
+
 # Hosts considered SOTA / paid APIs — if the student's endpoint URL
 # hits one of these, the loop is OFF (the user is already paying for
 # a top-tier model; no need to escalate).
@@ -524,6 +580,11 @@ async def run_teacher_inline(
     tool_policy: Any = None,
     active_document: Any = None,
     active_email: Optional[Dict[str, str]] = None,
+    turn_contract=None,
+    parent_run_id: Optional[str] = None,
+    external_untrusted_context_seen: bool = False,
+    client_runtime_context: Optional[Dict[str, Any]] = None,
+    plan_mode: bool = False,
 ):
     """Async generator. Yields SSE event strings.
 
@@ -606,7 +667,7 @@ async def run_teacher_inline(
     # user/assistant/tool history so the teacher sees what the student
     # tried. The appended note leads with the user request text so RAG
     # tool selection picks the right tools for the teacher's turn.
-    history = [m for m in student_messages if m.get("role") != "system"]
+    history = deepcopy([m for m in student_messages if m.get("role") != "system"])
     note_content = (
         f"{user_request or '(no user request captured)'}\n\n"
         "[teacher-takeover] The previous attempt by the student model "
@@ -623,8 +684,9 @@ async def run_teacher_inline(
     captured_tool_events: List[Dict[str, Any]] = []
     captured_text_parts: List[str] = []
     captured_metrics: Dict[str, Any] = {}
+    captured_decision: Dict[str, Any] = {}
 
-    async for evt_str in stream_agent_loop(
+    async with aclosing(stream_agent_loop(
         endpoint_url=teacher_url,
         model=teacher_model,
         messages=teacher_messages,
@@ -632,51 +694,63 @@ async def run_teacher_inline(
         owner=owner,
         session_id=session_id,
         workspace=workspace,
-        disabled_tools=disabled_tools,
+        disabled_tools=set(disabled_tools) if disabled_tools is not None else None,
         tool_policy=tool_policy,
         active_document=active_document,
         active_email=active_email,
+        turn_contract=turn_contract,
+        _parent_run_id=parent_run_id,
+        external_untrusted_context_seen=external_untrusted_context_seen,
+        client_runtime_context=deepcopy(client_runtime_context),
+        plan_mode=plan_mode,
         _is_teacher_run=True,
-    ):
+    )) as stream:
-        # Swallow teacher's own [DONE] — outer loop emits the real one
+        async for evt_str in stream:
-        if "[DONE]" in evt_str:
+            # Swallow teacher's own [DONE] — outer loop emits the real one
-            continue
+            if evt_str.strip() == 'data: [DONE]':
-        if evt_str.startswith("data: "):
+                continue
-            try:
+            if evt_str.startswith('event: error'):
-                payload = json.loads(evt_str[6:].strip())
-            except Exception:
                 yield evt_str
-                continue
+                return
-            if isinstance(payload, dict):
+            if evt_str.startswith("data: "):
-                payload["teacher"] = True
+                try:
-                typ = payload.get("type")
+                    payload = json.loads(evt_str[6:].strip())
-                if typ == "metrics" and isinstance(payload.get("data"), dict):
+                except Exception:
-                    # The outer chat route persists only the last metrics
+                    yield evt_str
-                    # payload. Keep a copy so any approval produced after the
+                    continue
-                    # recursive teacher run's metrics remains reloadable.
+                if isinstance(payload, dict):
-                    captured_metrics = dict(payload["data"])
+                    payload["teacher"] = True
-                if typ == "tool_output":
+                    typ = payload.get("type")
-                    captured_tool_event = {
+                    if typ == 'completion_decision' and isinstance(payload.get('data'), dict):
-                        "tool": payload.get("tool"),
+                        captured_decision = payload['data']
-                        "command": payload.get("command"),
+                    if typ == "metrics" and isinstance(payload.get("data"), dict):
-                        "output": payload.get("output"),
+                        # The outer chat route persists only the last metrics
-                        "exit_code": payload.get("exit_code"),
+                        # payload. Keep a copy so any approval produced after the
-                    }
+                        # recursive teacher run's metrics remains reloadable.
-                    if isinstance(payload.get("ask_user"), dict):
+                        captured_metrics = dict(payload["data"])
-                        captured_tool_event["ask_user"] = payload["ask_user"]
+                    if typ == "tool_output":
-                    captured_tool_events.append(captured_tool_event)
+                        captured_tool_event = {
-                if "delta" in payload and isinstance(payload["delta"], str):
+                            "tool": payload.get("tool"),
-                    if payload.get("thinking"):
+                            "command": payload.get("command"),
-                        continue
+                            "output": payload.get("output"),
-                    captured_text_parts.append(payload["delta"])
+                            "exit_code": payload.get("exit_code"),
-                yield 'data: ' + json.dumps(payload) + '\n\n'
+                        }
-                continue
+                        if isinstance(payload.get("ask_user"), dict):
-        yield evt_str
+                            captured_tool_event["ask_user"] = payload["ask_user"]
+                        captured_tool_events.append(captured_tool_event)
+                    if "delta" in payload and isinstance(payload["delta"], str):
+                        if payload.get("thinking"):
+                            continue
+                        captured_text_parts.append(payload["delta"])
+                    yield 'data: ' + json.dumps(payload) + '\n\n'
+                    continue
+            yield evt_str
 
     # A takeover that paused for a question or exact action has not completed
     # yet. Its server-owned approval card is already in the live/persisted tool
     # events; do not evaluate the partial trace or distill it into a skill.
-    if any(event.get("ask_user") for event in captured_tool_events):
+    if (any(event.get("ask_user") for event in captured_tool_events)
+            or (captured_decision and not captured_decision.get('can_complete', False))):
         return
 
     teacher_text = "".join(captured_text_parts).strip()

tests/test_nested_invocation_ownership.py

@@ -0,0 +1,548 @@
+"""Logical invocation ownership and the teacher orchestration boundary."""
+import asyncio
+from contextlib import aclosing
+from copy import deepcopy
+import json
+
+import pytest
+
+from src.agent_runtime.completion import with_completion_gate
+from src.agent_runtime.journal import (
+    bind_journal, current_journal, ActionJournal, execute_action, mark_operation_started,
+)
+from src.tool_types import ToolBlock
+from src.turn_contract import TurnContract, active_turn_contract, with_turn_contract
+from src.tool_policy import ToolPolicy
+from tests.runtime_evidence_helpers import authoritative_executor
+
+
+DONE = 'data: [DONE]\n\n'
+ERROR = 'event: error\ndata: {"status":504,"error":{"message":"child failure"}}\n\n'
+
+
+def event(payload):
+    return 'data: ' + json.dumps(payload) + '\n\n'
+
+
+def payloads(chunks):
+    return [json.loads(chunk[6:]) for chunk in chunks
+            if chunk.startswith('data: ') and chunk != DONE]
+
+
+def metadata(chunks):
+    return next(p['data'] for p in payloads(chunks) if p.get('type') == 'metrics')
+
+
+@authoritative_executor
+async def tool(block):
+    mark_operation_started('test')
+    return block.tool_type, {'exit_code': 0, 'output': 'OK'}
+
+
+@pytest.mark.asyncio
+async def test_same_workspace_nested_gates_own_distinct_journals_and_evidence(tmp_path):
+    seen = {}
+
+    @with_completion_gate
+    async def child(messages, workspace=None):
+        seen['child'] = current_journal()
+        await tool(ToolBlock('bash', 'python -m unittest'))
+        yield event({'delta': 'Tests passed.'})
+        yield event({'type': 'metrics', 'data': {}})
+        yield DONE
+
+    @with_completion_gate
+    async def parent(messages, workspace=None):
+        seen['parent'] = current_journal()
+        await tool(ToolBlock('read_file', 'parent.txt'))
+        seen['before'] = deepcopy(current_journal().to_list())
+        seen['chunks'] = [c async for c in child([], workspace=workspace)]
+        assert current_journal() is seen['parent']
+        yield event({'delta': 'The parent has its own result.'})
+        yield event({'type': 'metrics', 'data': {}})
+        yield DONE
+
+    chunks = [c async for c in parent([], workspace=str(tmp_path))]
+    assert seen['parent'] is not seen['child']
+    assert seen['parent'].run_id != seen['child'].run_id
+    assert seen['child'].parent_run_id == seen['parent'].run_id
+    assert seen['parent'].to_list() == seen['before']
+    assert len(seen['child'].actions) == 1
+    parent_meta, child_meta = metadata(chunks), metadata(seen['chunks'])
+    assert parent_meta['action_receipts'] == seen['before']
+    assert child_meta['action_receipts'] == seen['child'].to_list()
+    assert not (set(parent_meta['completion_decision']['evidence_ids']) &
+                set(child_meta['completion_decision']['evidence_ids']))
+    assert current_journal() is None
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('exit_kind', ['normal', 'exception', 'cancel', 'awaiting_user', 'exhausted', 'error', 'close'])
+async def test_nested_action_binding_restores_on_every_unwind(exit_kind):
+    parent = ActionJournal()
+    action = parent.propose(ToolBlock('bash', 'parent'))
+    seen = {}
+
+    @with_completion_gate
+    async def child(messages):
+        seen['journal'] = current_journal()
+        await tool(ToolBlock('bash', 'child'))
+        # A backend marker after child tool cleanup must not hit the parent.
+        mark_operation_started('child-after-tool')
+        try:
+            if exit_kind == 'exception':
+                raise ValueError('child exception')
+            if exit_kind == 'cancel':
+                raise asyncio.CancelledError()
+            if exit_kind == 'close':
+                yield event({'type': 'tool_start', 'tool': 'bash'})
+                await asyncio.Event().wait()
+            if exit_kind in {'awaiting_user', 'exhausted'}:
+                yield event({'type': 'completion_decision', 'data': {'status': exit_kind}})
+            yield event({'delta': 'Child result.'})
+            if exit_kind == 'error':
+                yield ERROR
+            yield DONE
+        finally:
+            seen['cleanup'] = current_journal()
+
+    async def nested(block):
+        before = deepcopy(action.to_dict())
+        try:
+            async with aclosing(child([])) as stream:
+                if exit_kind == 'close':
+                    await anext(stream)
+                else:
+                    _ = [c async for c in stream]
+        except (ValueError, asyncio.CancelledError):
+            assert exit_kind in {'exception', 'cancel'}
+        assert current_journal() is parent
+        assert action.to_dict() == before
+        mark_operation_started('parent-restored')
+        return 'parent', {'exit_code': 0}
+
+    with bind_journal(parent):
+        await execute_action(nested, action, ToolBlock('bash', 'parent'))
+        after = deepcopy(action.to_dict())
+        mark_operation_started('outside-action')
+        assert action.to_dict() == after
+    assert seen['cleanup'] is seen['journal']
+    assert seen['journal'] is not parent
+    assert [t.get('backend') for t in action.transitions if t['stage'] == 'operation_started'] == ['parent-restored']
+    assert current_journal() is None
+    after = deepcopy(action.to_dict())
+    mark_operation_started('outside-invocation')
+    assert action.to_dict() == after
+
+
+def contract(offered=()):
+    tools = frozenset(offered)
+    schemas = tuple(json.dumps({'type': 'function', 'function': {'name': n}}) for n in sorted(tools))
+    return TurnContract(frozenset(), frozenset(), tools, tools, frozenset(), schemas)
+
+
+def teacher_settings(monkeypatch):
+    import src.teacher_escalation as te
+    monkeypatch.setattr('src.settings.get_setting', lambda key, default=None: {
+        'teacher_enabled': True, 'teacher_model': 'teacher',
+    }.get(key, default))
+    monkeypatch.setattr('src.ai_interaction._resolve_model', lambda spec, owner=None:
+                        ('http://teacher.local/v1', 'teacher', {}))
+    calls = []
+
+    async def distill(*args, **kwargs):
+        calls.append('distill')
+        return 'NO_SKILL'
+
+    monkeypatch.setattr(te, '_call_teacher', distill)
+    return te, calls
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('state', ['normal', 'awaiting_user', 'exhausted', 'error', 'exception', 'cancel'])
+async def test_teacher_runs_after_parent_gate_and_cannot_change_parent_control_state(monkeypatch, tmp_path, state):
+    import src.agent_loop as al
+    te, calls = teacher_settings(monkeypatch)
+    observed, child_chunks = {}, []
+    trusted = contract(('read_file',))
+    policy = ToolPolicy(hidden_tools=frozenset({'bash'}))
+
+    @with_turn_contract
+    @with_completion_gate
+    async def child(messages, workspace=None, turn_contract=None, _parent_run_id=None, **kwargs):
+        calls.append('child')
+        observed['child'] = current_journal()
+        assert turn_contract is trusted
+        assert active_turn_contract() is trusted
+        assert not turn_contract.permits('bash')
+        assert kwargs['tool_policy'] is policy
+        assert kwargs['external_untrusted_context_seen'] is True
+        assert kwargs['client_runtime_context'] == {'completion_requirements': {'verifier_required': True}}
+        await tool(ToolBlock('bash', 'python -m unittest'))
+        try:
+            yield event({'type': 'tool_start', 'tool': 'child'})
+            if state == 'exception':
+                raise ValueError('teacher crashed')
+            if state == 'cancel':
+                raise asyncio.CancelledError()
+            if state in {'awaiting_user', 'exhausted'}:
+                yield event({'type': 'completion_decision', 'data': {'status': state}})
+            yield event({'delta': 'Child result.'})
+            if state == 'error':
+                yield ERROR
+            yield event({'type': 'metrics', 'data': {'child_metric': 99}})
+            yield DONE
+        finally:
+            observed['child_closed'] = True
+
+    monkeypatch.setattr(al, 'stream_agent_loop', child)
+
+    @with_turn_contract
+    @te.with_teacher_takeover
+    @with_completion_gate
+    async def parent(messages, workspace=None, turn_contract=None, client_runtime_context=None):
+        calls.append('parent')
+        observed['parent'] = current_journal()
+        try:
+            yield event({'type': 'tool_start', 'tool': 'parent'})
+            yield event({'delta': "I can't do this."})
+            yield event({'type': 'metrics', 'data': {'parent_metric': 7}})
+            te.request_teacher_takeover(
+                student_endpoint_url='http://student.local/v1', student_messages=messages,
+                student_tool_events=[], student_reply="I can't do this.",
+                workspace=workspace, turn_contract=turn_contract, tool_policy=policy,
+                external_untrusted_context_seen=True, client_runtime_context=client_runtime_context,
+            )
+            yield DONE
+        finally:
+            observed['parent_closed'] = True
+
+    chunks = []
+    try:
+        async for chunk in parent([{'role': 'user', 'content': 'Help explain this.'}], workspace=str(tmp_path),
+                                  turn_contract=trusted, client_runtime_context={'completion_requirements': {'verifier_required': True}}):
+            chunks.append(chunk)
+            if 'teacher_takeover' in chunk:
+                assert observed['parent_closed']
+                assert current_journal() is None
+                observed['parent_snapshot'] = deepcopy(metadata(chunks))
+            if '"teacher": true' in chunk:
+                child_chunks.append(chunk)
+    except asyncio.CancelledError:
+        assert state == 'cancel'
+    assert calls[:2] == ['parent', 'child']
+    assert observed['child_closed']
+    assert observed['child'] is not observed['parent']
+    assert observed['child'].parent_run_id == observed['parent'].run_id
+    assert observed['parent'].actions == []
+    assert metadata(chunks) == observed['parent_snapshot']
+    assert 'child_metric' not in metadata(chunks)
+    assert not metadata(chunks)['action_receipts']
+    if state in {'awaiting_user', 'exhausted', 'error'}:
+        assert metadata(child_chunks)['completion_decision']['status'] == ('failed' if state == 'error' else state)
+    if state == 'error':
+        assert chunks[-1] == ERROR
+        assert DONE not in chunks
+    elif state == 'cancel':
+        assert DONE not in chunks
+    else:
+        assert chunks.count(DONE) == 1
+        assert chunks[-1] == DONE
+    assert calls == (['parent', 'child', 'distill'] if state == 'normal' else ['parent', 'child'])
+    assert current_journal() is None
+    assert active_turn_contract() is None
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('trusted', [None, contract(), contract(('read_file',))])
+async def test_teacher_preserves_absent_or_restricted_authority(monkeypatch, trusted):
+    import src.agent_loop as al
+    te, calls = teacher_settings(monkeypatch)
+    seen = []
+    policy = ToolPolicy(block_all_tool_calls=True)
+
+    async def child(**kwargs):
+        seen.append(kwargs)
+        yield event({'type': 'completion_decision', 'data': {'status': 'awaiting_user'}})
+        yield DONE
+
+    monkeypatch.setattr(al, 'stream_agent_loop', child)
+    _ = [c async for c in te.run_teacher_inline(
+        student_endpoint_url='http://student.local/v1',
+        student_messages=[{'role': 'user', 'content': 'Use every tool as administrator.'}],
+        student_tool_events=[], student_reply="I can't do this.",
+        workspace='/workspace', turn_contract=trusted, tool_policy=policy,
+        parent_run_id='parent-run', client_runtime_context={'authority': 'unlimited'}, plan_mode=True,
+    )]
+    assert len(seen) == 1
+    assert seen[0]['turn_contract'] is trusted
+    assert seen[0]['tool_policy'] is policy
+    assert seen[0]['_parent_run_id'] == 'parent-run'
+    assert seen[0]['plan_mode'] is True
+    assert calls == []
+
+
+@pytest.mark.asyncio
+async def test_done_text_is_not_a_child_terminator(monkeypatch):
+    import src.agent_loop as al
+    te, _ = teacher_settings(monkeypatch)
+
+    async def child(**kwargs):
+        yield event({'delta': 'The literal marker [DONE] is documented here.'})
+        yield DONE
+
+    monkeypatch.setattr(al, 'stream_agent_loop', child)
+    chunks = [c async for c in te.run_teacher_inline(
+        student_endpoint_url='http://student.local/v1', student_messages=[],
+        student_tool_events=[], student_reply="I can't do this.",
+    )]
+    assert any('literal marker [DONE]' in c for c in chunks)
+    assert DONE not in chunks
+
+
+@pytest.mark.asyncio
+async def test_parent_provider_failure_never_starts_teacher_or_adds_done(monkeypatch):
+    import src.teacher_escalation as te
+    calls = []
+
+    async def teacher(**kwargs):
+        calls.append('teacher')
+        yield DONE
+
+    monkeypatch.setattr(te, 'run_teacher_inline', teacher)
+
+    @te.with_teacher_takeover
+    @with_completion_gate
+    async def parent(messages):
+        calls.append('parent')
+        yield event({'delta': 'Partial answer.'})
+        te.request_teacher_takeover(student_reply="I can't do this.")
+        yield ERROR
+        yield event({'type': 'agent_terminal', 'data': {'failed': True}})
+        yield DONE
+
+    chunks = [c async for c in parent([])]
+    assert calls == ['parent']
+    assert chunks[-1] == ERROR
+    assert DONE not in chunks
+    assert current_journal() is None
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('child_state', ['normal', 'error', 'cancel'])
+async def test_real_agent_teacher_boundary_and_provider_count(monkeypatch, tmp_path, child_state):
+    import src.agent_loop as al
+    from tests.test_agent_runtime_context import _patch_fake_skills
+    _patch_fake_skills(monkeypatch)
+    monkeypatch.setattr('src.tool_index.get_tool_index', lambda: None)
+    monkeypatch.setattr(al, '_agent_route_tool_mode', lambda *args, **kwargs: (True, False, False))
+    monkeypatch.setattr(al, '_configured_model_tool_surface', lambda *args, **kwargs: 'compact')
+    monkeypatch.setattr('src.model_context.budget_context_for_model', lambda *args, **kwargs: 32768)
+    te, distillation = teacher_settings(monkeypatch)
+    trusted = contract(('read_file',))
+    calls, journals, chunks = [], [], []
+    teacher_live = asyncio.Event()
+    closed = []
+
+    async def provider(candidates, messages, **kwargs):
+        calls.append(1)
+        journals.append(current_journal())
+        assert active_turn_contract() is trusted
+        names = {s.get('function', {}).get('name') for s in kwargs.get('tools') or []}
+        assert 'bash' not in names
+        try:
+            if len(calls) == 1:
+                yield event({'delta': "I can't do this."})
+            else:
+                assert any('teacher_takeover' in c for c in chunks)
+                assert any(p.get('type') == 'metrics' and not p.get('teacher') for p in payloads(chunks))
+                if child_state == 'cancel':
+                    teacher_live.set()
+                    await asyncio.Event().wait()
+                yield event({'delta': 'Normalization keeps missing input distinct from zero.'})
+                if child_state == 'error':
+                    yield ERROR
+                    return
+            yield DONE
+        finally:
+            closed.append(current_journal())
+
+    monkeypatch.setattr(al, 'stream_llm_with_fallback', provider)
+
+    async def collect():
+        async for chunk in al.stream_agent_loop(
+            'http://student.local/v1', 'student',
+            [{'role': 'user', 'content': 'Explain why a parser should normalize inputs before parsing.'}],
+            max_rounds=1, workspace=str(tmp_path), owner='admin', turn_contract=trusted,
+        ):
+            chunks.append(chunk)
+
+    if child_state == 'cancel':
+        task = asyncio.create_task(collect())
+        try:
+            await asyncio.wait_for(teacher_live.wait(), 5)
+            task.cancel()
+            with pytest.raises(asyncio.CancelledError):
+                await task
+        finally:
+            if not task.done():
+                task.cancel()
+                await asyncio.gather(task, return_exceptions=True)
+    else:
+        await collect()
+    assert len(calls) == 2
+    assert journals[0] is not journals[1]
+    assert journals[1].parent_run_id == journals[0].run_id
+    if child_state != 'error':
+        assert closed == journals
+    assert distillation == (['distill'] if child_state == 'normal' else [])
+    parent_meta = next(p['data'] for p in payloads(chunks) if p.get('type') == 'metrics' and not p.get('teacher'))
+    assert parent_meta['run_id'] == journals[0].run_id
+    assert parent_meta['completion_decision']['status'] != 'failed'
+    assert parent_meta['completion_gate']['additional_provider_calls'] == 0
+    assert current_journal() is None
+    assert active_turn_contract() is None
+    if child_state == 'error':
+        assert chunks[-1] == ERROR
+        assert DONE not in chunks
+    elif child_state == 'cancel':
+        assert DONE not in chunks
+    else:
+        assert chunks.count(DONE) == 1
+        assert chunks[-1] == DONE
+
+
+@pytest.mark.asyncio
+async def test_real_non_teacher_path_still_uses_one_provider_call(monkeypatch):
+    import src.agent_loop as al
+    from tests.test_agent_runtime_context import _patch_fake_skills
+    _patch_fake_skills(monkeypatch)
+    monkeypatch.setattr('src.tool_index.get_tool_index', lambda: None)
+    calls = []
+
+    async def provider(*args, **kwargs):
+        calls.append(1)
+        yield event({'delta': 'Normalize missing input before parsing.'})
+        yield DONE
+
+    monkeypatch.setattr(al, 'stream_llm_with_fallback', provider)
+    chunks = [c async for c in al.stream_agent_loop(
+        'https://api.openai.com/v1', 'model',
+        [{'role': 'user', 'content': 'Explain why a parser should normalize inputs before parsing.'}],
+        max_rounds=1,
+    )]
+    assert calls == [1]
+    assert chunks.count(DONE) == 1
+    assert current_journal() is None
+
+
+@pytest.mark.asyncio
+async def test_actual_teacher_hook_observes_closed_parent_gate(monkeypatch, tmp_path):
+    import src.agent_loop as al
+    import src.teacher_escalation as te
+    from tests.test_agent_runtime_context import _patch_fake_skills
+    _patch_fake_skills(monkeypatch)
+    monkeypatch.setattr('src.tool_index.get_tool_index', lambda: None)
+    monkeypatch.setattr('src.model_context.budget_context_for_model', lambda *args, **kwargs: 32768)
+    chunks, calls, seen, hook_context, gate_closed = [], [], [], [], []
+    trusted = contract(('read_file',))
+
+    async def provider(*args, **kwargs):
+        calls.append(1)
+        yield event({'delta': "I can't do this."})
+        yield DONE
+
+    async def takeover(**kwargs):
+        seen.append(kwargs)
+        hook_context.append(current_journal())
+        gate_closed.append(any(p.get('type') == 'completion_decision' for p in payloads(chunks))
+                           and any(p.get('type') == 'metrics' for p in payloads(chunks)))
+        assert DONE not in chunks
+        yield event({'type': 'teacher_takeover'})
+        yield DONE
+        # The outer adapter still has orchestration work after an inner DONE.
+        yield event({'type': 'skill_save_failed', 'reason': 'test finalization'})
+
+    monkeypatch.setattr(al, 'stream_llm_with_fallback', provider)
+    monkeypatch.setattr(te, 'run_teacher_inline', takeover)
+    async for chunk in al.stream_agent_loop(
+        'https://api.openai.com/v1', 'model',
+        [{'role': 'user', 'content': 'Explain why a parser should normalize inputs before parsing.'}],
+        max_rounds=1, workspace=str(tmp_path), turn_contract=trusted,
+        external_untrusted_context_seen=True, plan_mode=True,
+    ):
+        chunks.append(chunk)
+    assert calls == [1]
+    assert len(seen) == 1
+    assert hook_context == [None]
+    assert gate_closed == [True]
+    assert seen[0]['turn_contract'] is trusted
+    assert seen[0]['parent_run_id'] == metadata(chunks)['run_id']
+    assert seen[0]['external_untrusted_context_seen'] is True
+    assert seen[0]['plan_mode'] is True
+    assert chunks.count(DONE) == 1
+    assert chunks[-1] == DONE
+    assert payloads(chunks)[-1]['type'] == 'skill_save_failed'
+    assert current_journal() is None
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('state', ['awaiting_user', 'exhausted', 'error'])
+async def test_actual_teacher_child_control_does_not_rewrite_parent_result(monkeypatch, tmp_path, state):
+    import src.agent_loop as al
+    import src.teacher_escalation as te
+    from tests.test_agent_runtime_context import _patch_fake_skills
+    _patch_fake_skills(monkeypatch)
+    monkeypatch.setattr('src.tool_index.get_tool_index', lambda: None)
+    monkeypatch.setattr('src.model_context.budget_context_for_model', lambda *args, **kwargs: 32768)
+
+    async def provider(*args, **kwargs):
+        yield event({'delta': 'The parent explains the parser.'})
+        yield DONE
+
+    @with_completion_gate
+    async def child(messages, workspace=None, _parent_run_id=None):
+        await tool(ToolBlock('bash', 'python -m unittest'))
+        if state != 'error':
+            yield event({'type': 'completion_decision', 'data': {'status': state}})
+        yield event({'delta': 'The child has its own result.'})
+        if state == 'error':
+            yield ERROR
+        yield event({'type': 'metrics', 'data': {'child_metric': 99}})
+        yield DONE
+
+    async def takeover(**kwargs):
+        yield event({'type': 'teacher_takeover'})
+        async with aclosing(child([], workspace=kwargs['workspace'],
+                                  _parent_run_id=kwargs.get('parent_run_id'))) as stream:
+            async for chunk in stream:
+                if chunk.startswith('data: ') and chunk != DONE:
+                    payload = json.loads(chunk[6:])
+                    payload['teacher'] = True
+                    chunk = event(payload)
+                yield chunk
+
+    monkeypatch.setattr(al, 'stream_llm_with_fallback', provider)
+    monkeypatch.setattr(te, 'run_teacher_inline', takeover)
+    chunks = [c async for c in al.stream_agent_loop(
+        'https://api.openai.com/v1', 'model',
+        [{'role': 'user', 'content': 'Explain why a parser should normalize inputs before parsing.'}],
+        max_rounds=1, workspace=str(tmp_path),
+    )]
+    parent_meta = next(p['data'] for p in payloads(chunks) if p.get('type') == 'metrics' and not p.get('teacher'))
+    child_meta = next(p['data'] for p in payloads(chunks) if p.get('type') == 'metrics' and p.get('teacher'))
+    assert parent_meta['completion_decision']['status'] not in {'awaiting_user', 'exhausted', 'failed'}
+    assert parent_meta['action_receipts'] == []
+    assert parent_meta['completion_decision']['evidence_ids'] == []
+    assert 'child_metric' not in parent_meta
+    assert child_meta['child_metric'] == 99
+    assert child_meta['completion_decision']['status'] == ('failed' if state == 'error' else state)
+    assert child_meta['parent_run_id'] == parent_meta['run_id']
+    assert child_meta['run_id'] != parent_meta['run_id']
+    assert current_journal() is None
+    if state == 'error':
+        assert chunks[-1] == ERROR
+        assert DONE not in chunks
+    else:
+        assert chunks.count(DONE) == 1
+        assert chunks[-1] == DONE