wip: fix mission bus test loader

config/mission_bus_profiles.json

@@ -0,0 +1,34 @@
+{
+  "roles": {
+    "lead": ["publish", "checkpoint", "handoff", "read", "audit", "configure_isolation"],
+    "write": ["publish", "checkpoint", "handoff", "read"],
+    "read": ["read"],
+    "audit": ["read", "audit"]
+  },
+  "isolation_profiles": [
+    {
+      "name": "level1-directory",
+      "label": "Level 1 — directory workspace",
+      "level": 1,
+      "mechanism": "directory_workspace",
+      "description": "Single mission cell in an isolated workspace directory.",
+      "supports_resume": true
+    },
+    {
+      "name": "level2-mount-namespace",
+      "label": "Level 2 — mount namespace",
+      "level": 2,
+      "mechanism": "mount_namespace",
+      "description": "Mount-namespace isolation with explicit mission-cell mounts.",
+      "supports_resume": true
+    },
+    {
+      "name": "level3-rootless-podman",
+      "label": "Level 3 — rootless Podman",
+      "level": 3,
+      "mechanism": "rootless_podman",
+      "description": "Rootless Podman cell for the strongest process and filesystem containment.",
+      "supports_resume": true
+    }
+  ]
+}

docs/mission-bus.md

@@ -0,0 +1,31 @@
+# Mission Bus
+
+The Mission Bus grounds the multi-agent teaming epic with a concrete, executable shared module.
+
+## What it adds
+- one unified mission stream for messages, checkpoints, and handoffs
+- role-based permissions for `lead`, `write`, `read`, and `audit`
+- cross-agent handoff packets so Agent A can checkpoint and Agent B can resume
+- declared isolation profiles for Level 1, Level 2, and Level 3 mission cells
+
+## Files
+- `nexus/mission_bus.py`
+- `config/mission_bus_profiles.json`
+
+## Example
+
+```python
+from nexus.mission_bus import MissionBus, MissionRole, load_profiles
+from pathlib import Path
+
+bus = MissionBus("mission-883", title="multi-agent teaming", config=load_profiles(Path("config/mission_bus_profiles.json")))
+bus.register_participant("timmy", MissionRole.LEAD)
+bus.register_participant("ezra", MissionRole.WRITE)
+checkpoint = bus.create_checkpoint("ezra", summary="checkpoint", state={"branch": "fix/883"})
+bus.handoff("ezra", "timmy", checkpoint.checkpoint_id, note="resume from here")
+packet = bus.build_resume_packet(bus.events[-1].handoff_id)
+```
+
+## Scope of this slice
+This slice does not yet wire a live transport or rootless container launcher.
+It codifies the mission bus contract, role permissions, handoff packet, and isolation profile surface so later work can execute against a stable interface.

nexus/__init__.py

@@ -14,6 +14,16 @@ from nexus.perception_adapter import (
 )
 from nexus.experience_store import ExperienceStore
 from nexus.trajectory_logger import TrajectoryLogger
+from nexus.mission_bus import (
+    MissionBus,
+    MissionRole,
+    MissionParticipant,
+    MissionMessage,
+    MissionCheckpoint,
+    MissionHandoff,
+    IsolationProfile,
+    load_profiles,
+)
 
 try:
     from nexus.nexus_think import NexusMind
@@ -28,5 +38,13 @@ __all__ = [
     "Action",
     "ExperienceStore",
     "TrajectoryLogger",
+    "MissionBus",
+    "MissionRole",
+    "MissionParticipant",
+    "MissionMessage",
+    "MissionCheckpoint",
+    "MissionHandoff",
+    "IsolationProfile",
+    "load_profiles",
     "NexusMind",
 ]

nexus/mission_bus.py

@@ -0,0 +1,358 @@
+"""Mission bus, role permissions, cross-agent handoff, and isolation profiles.
+
+Grounded implementation slice for #883.
+The bus gives a single mission cell a unified event stream, permission-checked
+roles, checkpoint + resume handoff, and declared isolation profiles for Level
+1/2/3 execution boundaries.
+"""
+
+from __future__ import annotations
+
+import json
+import uuid
+from dataclasses import dataclass, field
+from datetime import datetime, timezone
+from enum import Enum
+from pathlib import Path
+from typing import Any, Dict, List, Union
+
+
+DEFAULT_CONFIG = {
+    "roles": {
+        "lead": ["publish", "checkpoint", "handoff", "read", "audit", "configure_isolation"],
+        "write": ["publish", "checkpoint", "handoff", "read"],
+        "read": ["read"],
+        "audit": ["read", "audit"],
+    },
+    "isolation_profiles": [
+        {
+            "name": "level1-directory",
+            "label": "Level 1 — directory workspace",
+            "level": 1,
+            "mechanism": "directory_workspace",
+            "description": "Single mission cell in an isolated workspace directory.",
+            "supports_resume": True,
+        },
+        {
+            "name": "level2-mount-namespace",
+            "label": "Level 2 — mount namespace",
+            "level": 2,
+            "mechanism": "mount_namespace",
+            "description": "Mount-namespace isolation with explicit mission-cell mounts.",
+            "supports_resume": True,
+        },
+        {
+            "name": "level3-rootless-podman",
+            "label": "Level 3 — rootless Podman",
+            "level": 3,
+            "mechanism": "rootless_podman",
+            "description": "Rootless Podman cell for the strongest process and filesystem containment.",
+            "supports_resume": True,
+        },
+    ],
+}
+
+
+def utcnow_iso() -> str:
+    return datetime.now(timezone.utc).isoformat()
+
+
+def load_profiles(path: Path) -> Dict[str, Any]:
+    if not path.exists():
+        return json.loads(json.dumps(DEFAULT_CONFIG))
+    with open(path, "r", encoding="utf-8") as handle:
+        data = json.load(handle)
+    data.setdefault("roles", DEFAULT_CONFIG["roles"])
+    data.setdefault("isolation_profiles", DEFAULT_CONFIG["isolation_profiles"])
+    return data
+
+
+class MissionRole(str, Enum):
+    LEAD = "lead"
+    WRITE = "write"
+    READ = "read"
+    AUDIT = "audit"
+
+
+@dataclass
+class IsolationProfile:
+    name: str
+    label: str
+    level: int
+    mechanism: str
+    description: str = ""
+    supports_resume: bool = True
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "name": self.name,
+            "label": self.label,
+            "level": self.level,
+            "mechanism": self.mechanism,
+            "description": self.description,
+            "supports_resume": self.supports_resume,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "IsolationProfile":
+        return cls(
+            name=data["name"],
+            label=data["label"],
+            level=int(data["level"]),
+            mechanism=data["mechanism"],
+            description=data.get("description", ""),
+            supports_resume=bool(data.get("supports_resume", True)),
+        )
+
+
+@dataclass
+class MissionParticipant:
+    name: str
+    role: MissionRole
+    metadata: Dict[str, Any] = field(default_factory=dict)
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "name": self.name,
+            "role": self.role.value,
+            "metadata": self.metadata,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "MissionParticipant":
+        return cls(name=data["name"], role=MissionRole(data["role"]), metadata=data.get("metadata", {}))
+
+
+@dataclass
+class MissionMessage:
+    sender: str
+    topic: str
+    payload: Dict[str, Any]
+    sequence: int
+    timestamp: str = field(default_factory=utcnow_iso)
+    message_id: str = field(default_factory=lambda: str(uuid.uuid4()))
+    event_type: str = field(default="message", init=False)
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "event_type": self.event_type,
+            "sender": self.sender,
+            "topic": self.topic,
+            "payload": self.payload,
+            "sequence": self.sequence,
+            "timestamp": self.timestamp,
+            "message_id": self.message_id,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "MissionMessage":
+        return cls(
+            sender=data["sender"],
+            topic=data["topic"],
+            payload=data["payload"],
+            sequence=int(data["sequence"]),
+            timestamp=data.get("timestamp", utcnow_iso()),
+            message_id=data.get("message_id") or data.get("messageId") or str(uuid.uuid4()),
+        )
+
+
+@dataclass
+class MissionCheckpoint:
+    sender: str
+    summary: str
+    state: Dict[str, Any]
+    sequence: int
+    artifacts: List[str] = field(default_factory=list)
+    timestamp: str = field(default_factory=utcnow_iso)
+    checkpoint_id: str = field(default_factory=lambda: str(uuid.uuid4()))
+    event_type: str = field(default="checkpoint", init=False)
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "event_type": self.event_type,
+            "sender": self.sender,
+            "summary": self.summary,
+            "state": self.state,
+            "artifacts": self.artifacts,
+            "sequence": self.sequence,
+            "timestamp": self.timestamp,
+            "checkpoint_id": self.checkpoint_id,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "MissionCheckpoint":
+        return cls(
+            sender=data["sender"],
+            summary=data["summary"],
+            state=data.get("state", {}),
+            artifacts=list(data.get("artifacts", [])),
+            sequence=int(data["sequence"]),
+            timestamp=data.get("timestamp", utcnow_iso()),
+            checkpoint_id=data.get("checkpoint_id") or data.get("checkpointId") or str(uuid.uuid4()),
+        )
+
+
+@dataclass
+class MissionHandoff:
+    sender: str
+    recipient: str
+    checkpoint_id: str
+    sequence: int
+    note: str = ""
+    timestamp: str = field(default_factory=utcnow_iso)
+    handoff_id: str = field(default_factory=lambda: str(uuid.uuid4()))
+    event_type: str = field(default="handoff", init=False)
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "event_type": self.event_type,
+            "sender": self.sender,
+            "recipient": self.recipient,
+            "checkpoint_id": self.checkpoint_id,
+            "note": self.note,
+            "sequence": self.sequence,
+            "timestamp": self.timestamp,
+            "handoff_id": self.handoff_id,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "MissionHandoff":
+        return cls(
+            sender=data["sender"],
+            recipient=data["recipient"],
+            checkpoint_id=data["checkpoint_id"] if "checkpoint_id" in data else data["checkpointId"],
+            note=data.get("note", ""),
+            sequence=int(data["sequence"]),
+            timestamp=data.get("timestamp", utcnow_iso()),
+            handoff_id=data.get("handoff_id") or data.get("handoffId") or str(uuid.uuid4()),
+        )
+
+
+MissionEvent = Union[MissionMessage, MissionCheckpoint, MissionHandoff]
+
+
+def event_from_dict(data: Dict[str, Any]) -> MissionEvent:
+    kind = data["event_type"]
+    if kind == "message":
+        return MissionMessage.from_dict(data)
+    if kind == "checkpoint":
+        return MissionCheckpoint.from_dict(data)
+    if kind == "handoff":
+        return MissionHandoff.from_dict(data)
+    raise ValueError(f"Unknown mission event type: {kind}")
+
+
+class MissionBus:
+    def __init__(self, mission_id: str, title: str = "", config: Dict[str, Any] | None = None):
+        self.mission_id = mission_id
+        self.title = title
+        self.config = config or json.loads(json.dumps(DEFAULT_CONFIG))
+        self.role_permissions = {
+            role: set(perms) for role, perms in self.config.get("roles", {}).items()
+        }
+        self.isolation_profiles = [
+            IsolationProfile.from_dict(entry) for entry in self.config.get("isolation_profiles", [])
+        ]
+        self.participants: Dict[str, MissionParticipant] = {}
+        self.events: List[MissionEvent] = []
+
+    def register_participant(self, name: str, role: MissionRole, metadata: Dict[str, Any] | None = None) -> MissionParticipant:
+        participant = MissionParticipant(name=name, role=role, metadata=metadata or {})
+        self.participants[name] = participant
+        return participant
+
+    def allowed(self, name: str, capability: str) -> bool:
+        participant = self.participants.get(name)
+        if participant is None:
+            return False
+        return capability in self.role_permissions.get(participant.role.value, set())
+
+    def _require(self, name: str, capability: str) -> None:
+        if not self.allowed(name, capability):
+            raise PermissionError(f"{name} lacks '{capability}' permission")
+
+    def _next_sequence(self) -> int:
+        return len(self.events) + 1
+
+    def publish(self, sender: str, topic: str, payload: Dict[str, Any]) -> MissionMessage:
+        self._require(sender, "publish")
+        event = MissionMessage(sender=sender, topic=topic, payload=payload, sequence=self._next_sequence())
+        self.events.append(event)
+        return event
+
+    def create_checkpoint(
+        self,
+        sender: str,
+        summary: str,
+        state: Dict[str, Any],
+        artifacts: List[str] | None = None,
+    ) -> MissionCheckpoint:
+        self._require(sender, "checkpoint")
+        event = MissionCheckpoint(
+            sender=sender,
+            summary=summary,
+            state=state,
+            artifacts=list(artifacts or []),
+            sequence=self._next_sequence(),
+        )
+        self.events.append(event)
+        return event
+
+    def _get_checkpoint(self, checkpoint_id: str) -> MissionCheckpoint:
+        for event in self.events:
+            if isinstance(event, MissionCheckpoint) and event.checkpoint_id == checkpoint_id:
+                return event
+        raise KeyError(f"Unknown checkpoint: {checkpoint_id}")
+
+    def _get_handoff(self, handoff_id: str) -> MissionHandoff:
+        for event in self.events:
+            if isinstance(event, MissionHandoff) and event.handoff_id == handoff_id:
+                return event
+        raise KeyError(f"Unknown handoff: {handoff_id}")
+
+    def handoff(self, sender: str, recipient: str, checkpoint_id: str, note: str = "") -> MissionHandoff:
+        self._require(sender, "handoff")
+        if recipient not in self.participants:
+            raise KeyError(f"Unknown recipient: {recipient}")
+        self._get_checkpoint(checkpoint_id)
+        event = MissionHandoff(
+            sender=sender,
+            recipient=recipient,
+            checkpoint_id=checkpoint_id,
+            note=note,
+            sequence=self._next_sequence(),
+        )
+        self.events.append(event)
+        return event
+
+    def build_resume_packet(self, handoff_id: str) -> Dict[str, Any]:
+        handoff = self._get_handoff(handoff_id)
+        checkpoint = self._get_checkpoint(handoff.checkpoint_id)
+        return {
+            "mission_id": self.mission_id,
+            "title": self.title,
+            "recipient": handoff.recipient,
+            "sender": handoff.sender,
+            "handoff_note": handoff.note,
+            "checkpoint": checkpoint.to_dict(),
+            "participants": {name: participant.to_dict() for name, participant in self.participants.items()},
+            "isolation_profiles": [profile.to_dict() for profile in self.isolation_profiles],
+            "stream_length": len(self.events),
+        }
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "mission_id": self.mission_id,
+            "title": self.title,
+            "config": self.config,
+            "participants": {name: participant.to_dict() for name, participant in self.participants.items()},
+            "events": [event.to_dict() for event in self.events],
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "MissionBus":
+        bus = cls(data["mission_id"], title=data.get("title", ""), config=data.get("config"))
+        for name, participant_data in data.get("participants", {}).items():
+            bus.participants[name] = MissionParticipant.from_dict(participant_data)
+        bus.events = [event_from_dict(event_data) for event_data in data.get("events", [])]
+        return bus

tests/test_mission_bus.py

@@ -0,0 +1,107 @@
+from importlib import util
+from pathlib import Path
+import sys
+
+import pytest
+
+
+ROOT = Path(__file__).resolve().parent.parent
+MODULE_PATH = ROOT / "nexus" / "mission_bus.py"
+CONFIG_PATH = ROOT / "config" / "mission_bus_profiles.json"
+
+
+def load_module():
+    spec = util.spec_from_file_location("mission_bus", MODULE_PATH)
+    module = util.module_from_spec(spec)
+    assert spec.loader is not None
+    sys.modules[spec.name] = module
+    spec.loader.exec_module(module)
+    return module
+
+
+def build_bus(module):
+    profiles = module.load_profiles(CONFIG_PATH)
+    bus = module.MissionBus("mission-883", title="multi-agent teaming", config=profiles)
+    bus.register_participant("timmy", module.MissionRole.LEAD)
+    bus.register_participant("ezra", module.MissionRole.WRITE)
+    bus.register_participant("bezalel", module.MissionRole.READ)
+    bus.register_participant("allegro", module.MissionRole.AUDIT)
+    return bus
+
+
+def test_role_permissions_gate_publish_checkpoint_and_handoff():
+    module = load_module()
+    bus = build_bus(module)
+
+    assert bus.allowed("timmy", "publish") is True
+    assert bus.allowed("ezra", "handoff") is True
+    assert bus.allowed("allegro", "audit") is True
+    assert bus.allowed("bezalel", "publish") is False
+
+    with pytest.raises(PermissionError):
+        bus.publish("bezalel", "mission.notes", {"text": "should fail"})
+
+    with pytest.raises(PermissionError):
+        bus.create_checkpoint("allegro", summary="audit cannot checkpoint", state={})
+
+
+def test_mission_bus_unified_stream_records_messages_checkpoints_and_handoffs():
+    module = load_module()
+    bus = build_bus(module)
+
+    msg = bus.publish("timmy", "mission.start", {"goal": "build the slice"})
+    checkpoint = bus.create_checkpoint(
+        "ezra",
+        summary="checkpoint before lead review",
+        state={"branch": "fix/883", "files": ["nexus/mission_bus.py"]},
+        artifacts=["docs/mission-bus.md"],
+    )
+    handoff = bus.handoff("ezra", "timmy", checkpoint.checkpoint_id, note="ready for lead review")
+
+    assert [event.event_type for event in bus.events] == ["message", "checkpoint", "handoff"]
+    assert [event.sequence for event in bus.events] == [1, 2, 3]
+    assert msg.topic == "mission.start"
+    assert handoff.recipient == "timmy"
+
+
+def test_handoff_resume_packet_contains_checkpoint_state_and_participants():
+    module = load_module()
+    bus = build_bus(module)
+    checkpoint = bus.create_checkpoint(
+        "ezra",
+        summary="handoff package",
+        state={"branch": "fix/883", "tests": ["tests/test_mission_bus.py"]},
+        artifacts=["config/mission_bus_profiles.json"],
+    )
+    handoff = bus.handoff("ezra", "timmy", checkpoint.checkpoint_id, note="pick up from here")
+
+    packet = bus.build_resume_packet(handoff.handoff_id)
+    assert packet["recipient"] == "timmy"
+    assert packet["checkpoint"]["state"]["branch"] == "fix/883"
+    assert packet["checkpoint"]["artifacts"] == ["config/mission_bus_profiles.json"]
+    assert packet["participants"]["ezra"]["role"] == "write"
+    assert packet["handoff_note"] == "pick up from here"
+
+
+def test_profiles_define_level2_mount_namespace_and_level3_rootless_podman():
+    module = load_module()
+    profiles = module.load_profiles(CONFIG_PATH)
+
+    levels = {entry["level"]: entry["mechanism"] for entry in profiles["isolation_profiles"]}
+    assert levels[2] == "mount_namespace"
+    assert levels[3] == "rootless_podman"
+    assert profiles["roles"]["audit"] == ["read", "audit"]
+
+
+def test_mission_bus_roundtrip_preserves_events_and_isolation_profile():
+    module = load_module()
+    bus = build_bus(module)
+    bus.publish("timmy", "mission.start", {"goal": "roundtrip"})
+    checkpoint = bus.create_checkpoint("ezra", summary="save state", state={"count": 1})
+    bus.handoff("ezra", "timmy", checkpoint.checkpoint_id, note="resume")
+
+    restored = module.MissionBus.from_dict(bus.to_dict())
+    assert restored.mission_id == "mission-883"
+    assert restored.events[-1].event_type == "handoff"
+    assert restored.events[-1].note == "resume"
+    assert restored.isolation_profiles[1].mechanism == "mount_namespace"