Hollow

Multi-Agent Consensus

Consensus is how the system makes decisions that are too consequential for any single agent to make alone.

What's new

agents/consensus.py — ConsensusManager with:

• propose() — submit action with participants and required vote count
• vote() — cast accept/reject; triggers early rejection when quorum is mathematically impossible
• withdraw() — proposer cancels a pending proposal
• list_for_agent() — proposals where agent is proposer or participant
• Background reaper thread expires stale proposals every 10s

5 new API routes

POST   /consensus/propose
POST   /consensus/{id}/vote
GET    /consensus/{id}
GET    /agents/{id}/consensus
DELETE /consensus/{id}

4 new MCP tools: consensus_propose, consensus_vote, consensus_status, consensus_list

6 new event types: consensus.proposed, consensus.vote_requested, consensus.vote_cast, consensus.reached, consensus.rejected, consensus.expired

7 integration tests — unanimous acceptance, early rejection (quorum impossible), majority quorum, participant enforcement, duplicate vote rejection, withdrawal, list/status.

Design notes

Execution is out of scope by design. consensus.reached carries the full action payload; the proposer acts on it. To couple consensus to a transaction: include {"txn_id": "..."} in the action dict and listen for consensus.reached before committing. Pre-commit checkpoints (v1.3.3) ensure rollback is possible if anything fails post-consensus.

Requires: events (v0.7.0) for vote distribution, transactions (v1.2.0) as the primary action type consensus gates.