xmtp-comms-guard — Skill Integration Guide (V6)

Type: Critical Security Version: 6.0.0 Required peer dependencies: bagman, pii-guard, prompt-guard

Mandatory Usage

All XMTP communication MUST go through the guarded client:

import { createGuardedXmtpClient } from "xmtp-comms-guard";
const { client, middleware } = await createGuardedXmtpClient(rawClient, userWallet);

Raw @xmtp/client imports are blocked by ESLint rules and SkillGuard scan.

Three-Shift Integration

Three-Shift = EverClaw's standard approval flow with three options:

• Approve — allow the action
• Redact — downgrade/sanitize
• Block — deny the action

Used for: peer revocation review, key rotation re-approval, introduction chain re-evaluation.

Enforcement Model

Enforcement is convention-based + build-time gates:

• ESLint rule blocks @xmtp/client direct imports
• SkillGuard scan detects raw client usage patterns
• No runtime interception of raw imports (honestly documented)

See enforcement.md for full details.

Fail-Closed Conditions

The skill refuses to operate when:

• Hash chain integrity check fails on startup
• SQLCipher encryption check fails
• Nonce cache detects replay
• Unknown topic in message
• Unknown sensitivity level
• Message exceeds 64KB
• Protocol version is not "6.0"
• Peer not in registry or blocked

Threat Model

Covered in threat-model.md:

• Malicious external agent → blocked by schema + checks
• Compromised internal agent → blocked by middleware + SkillGuard gates
• Host compromise → limited by Bagman + HMAC chain + fail-closed
• Replay attacks → nonce cache (90s TTL) + hash chain
• Data exfiltration → PII Guard + trust context rules