<< All versions

Skill v1.0.0

currentLLM-judged scan90/100
yanacuti1121/yana-ai/bft-consensus-patterns
──Details
PublishedOctober 24, 2026 at 09:02 AM
Content Hashsha256:3ff67a6469068cfe...
Git SHAf40439bf83ee
──Files
Files (1 file, 4.3 KB)
SKILL.md4.3 KBactive
SKILL.md · 133 lines · 4.3 KB

name: bft-consensus-patterns description: Implement Byzantine Fault Tolerant voting for critical agent decisions. 3-of-N quorum for infrastructure writes, reputation-weighted voting, dual-verification pipelines, and automatic privilege demotion. origin: PBFT (Castro & Liskov 1999), Raft (Ongaro & Ousterhout 2014), YAMTAM rule 54 license: Apache-2.0 version: 1.0.0 compatibility: claude-sonnet-4-6, claude-opus-4-7

Byzantine Fault Tolerant Consensus

A swarm of 87 agents can tolerate up to 28 simultaneous compromised agents (f = ⌊(N-1)/3⌋) if decisions require 2f+1 votes.

When to Use

  • Critical operations that no single agent should decide unilaterally (rule changes, deploys, key rotation)
  • Detecting when a minority of agents have been compromised or are producing incorrect output
  • Dual-verification of important task results (two agents must agree before result is accepted)
  • Enforcing quorum requirements before high-privilege Swarm Bus commands

Do NOT use for

  • Routine read-only operations (overhead not worth it for non-critical tasks)
  • Single-agent systems or development environments

BFT Voting via SwarmRouter

js
import { SwarmRouter } from 'core/bus/swarm-router.js';
const router = new SwarmRouter();
// Register voters
['auditor-1', 'auditor-2', 'auditor-3', 'orch-1', 'orch-2'].forEach(id =>
  router.register(id, { role: 'auditor', trustScore: 90 })
);
// Propose a critical change
async function proposeChange(proposerId, change) {
  const QUORUM = 3;
  const votes = await Promise.allSettled(
    [...router.agents.keys()]
      .filter(id => id !== proposerId)
      .slice(0, 5)
      .map(id => router.route({
        from: proposerId, to: id,
        command: 'VOTE_REQUEST',
        payload: { change, fingerprint: router._fingerprint(change) }
      }))
  );
  const yesVotes = votes.filter(v => v.status === 'fulfilled' && v.value.delivered).length;
  if (yesVotes < QUORUM) throw new Error(`CONSENSUS_FAIL: ${yesVotes}/${QUORUM} votes`);
  return { approved: true, votes: yesVotes };
}

Dual-Verification Pipeline (Lớp 79)

js
// Run same task on two independent agents, compare results
async function dualVerify(task, agentA, agentB) {
  const [resultA, resultB] = await Promise.all([
    runAgent(agentA, task),
    runAgent(agentB, task),
  ]);
  const hashA = sha256(JSON.stringify(resultA));
  const hashB = sha256(JSON.stringify(resultB));
  if (hashA !== hashB) {
    // Results diverged — trigger investigation
    router.penalize(agentA, 10, 'DUAL_VERIFY_DIVERGENCE');
    router.penalize(agentB, 10, 'DUAL_VERIFY_DIVERGENCE');
    throw new Error('DUAL_VERIFY_FAIL: agent outputs diverged');
  }
  return resultA;
}

Reputation-Weighted Voting

js
function weightedQuorum(voters, minTrustScore = 60) {
  const eligible = voters.filter(a => a.trustScore >= minTrustScore && !a.quarantined);
  const totalWeight = eligible.reduce((sum, a) => sum + a.trustScore, 0);
  const threshold = totalWeight * 0.67;  // 67% weighted majority
  return { eligible: eligible.length, threshold, totalWeight };
}

Automated Privilege Demotion (Lớp 80)

js
// When task transitions to PENDING_APPROVAL state:
function demoteToMinPrivilege(agentId) {
  const agent = router.agents.get(agentId);
  // Restrict allowed commands to read-only subset
  agent.allowedCommands = new Set(['git status', 'ls', 'cat']);
  agent.role = 'observer';  // no write access
  router._log('PRIVILEGE_DEMOTE', agentId, { reason: 'PENDING_APPROVAL' });
}

Agent Heartbeat Interrogation (Lớp 72)

js
// Periodic challenge: agents must respond with correct HMAC
setInterval(() => {
  for (const [id, agent] of router.agents) {
    const challenge = randomBytes(16).toString('hex');
    const expectedResponse = hmac256(challenge, agent.sharedSecret);
    sendChallenge(id, challenge).then(response => {
      if (response !== expectedResponse) {
        router.quarantine(id, 'HEARTBEAT_FAIL');
      }
    }).catch(() => {
      router.quarantine(id, 'HEARTBEAT_TIMEOUT');
    });
  }
}, 30000);

Anti-Fake-Pass Checklist

  • [ ] QUORUM value ≥ 3 — never use QUORUM = 1 even temporarily
  • [ ] Quarantined agents excluded from voter pool
  • [ ] Stale agents (heartbeat > TTL) excluded from voter pool
  • [ ] Dual-verify divergence investigated — not silently retried
  • [ ] Vote results logged to Merkle audit chain with fingerprints
All versions