feat: Multi-Chat Awareness & Cross-Thread State Sharing

[gdeyoung]

Multi-Chat Awareness & Cross-Thread State Sharing

Problem

When running multiple concurrent chat threads in Agent Zero, agents have no visibility into what other threads are doing. This leads to:

• Silent conflicts — Multiple threads modifying the same files simultaneously
• Duplicate work — No way to see if another thread is already working on a task
• Lost context — Tasks created by one thread are invisible to all others
• No task provenance — No way to know which chat thread created which scheduled task

Solution

This PR adds automatic cross-thread state sharing with minimal surface area:

1. Task Source Chat (Core: 7 lines across 2 files)

• Adds source_chat: Optional[str] = Field(default=None) to BaseTask in task_scheduler.py
• Captures self.agent.context.id in all 3 task creation methods in scheduler.py
• Enables task provenance — every task knows which chat created it

2. Three Framework Extensions (208 lines across 3 files)

Extension	Hook	Purpose
_20_register_chat_state.py	agent_init	Auto-registers each new chat thread in shared state
_20_inject_cross_thread_state.py	message_loop_start	Injects other threads activity into agent context every turn
_20_log_cross_thread_turn.py	message_loop_end	Auto-logs each turn for cross-thread visibility

3. Thread-Safe State File

Extensions use ~/.a0_cross_thread_state.json with fcntl.flock for atomic reads/writes. No external dependencies — pure stdlib.

Architecture

NEW CHAT THREAD STARTS
└── agent_init extension → registers chat in shared state

EVERY MESSAGE LOOP TURN
├── message_loop_start → reads shared state, injects summary
│ Shows: active chats, recent changes, open issues
└── message_loop_end → logs turn activity to shared state
Records: chat_id, action summary, timestamp

SCHEDULER CREATES TASK
└── task.source_chat = agent.context.id
Every task knows its originating chat

Backward Compatibility

• 100% backward compatible — source_chat defaults to None
• No core behavior changes — extensions are additive
• No new dependencies — uses only Python stdlib (json, fcntl, os)
• Opt-in at runtime — extensions only activate if state file exists

Testing

Running in production with 19 concurrent scheduled tasks and 34 active chat threads:

• Thread-safe concurrent writes verified (10 parallel writes, 0 corruption)
• Auto-registration working for new chats
• Cross-thread state injection working every turn
• Task source_chat captured for all new tasks

Files Changed

helpers/task_scheduler.py | 1 +
tools/scheduler.py | 6 ++
extensions/python/agent_init/_20_register_chat_state.py | 73 +++++++++
extensions/python/message_loop_start/_20_inject_cross_thread_state.py | 52 ++++++
extensions/python/message_loop_end/_20_log_cross_thread_turn.py | 83 ++++++++++
5 files changed, 215 insertions(+)