OpenFGA Real-Time Tuple Consistency Barrier for Multi-Region ReBAC

--- description: OpenFGA Real-Time Tuple Consistency Barrier for Multi-Region ReBAC - Enforces real-time consistency barriers and causal token propagation across distributed edge nodes in OpenFGA ReBAC architectures. Eliminates replication-lag authorization bypass windows and Zanzibar 'New Enemy' vulnerabilities by mandating explicit consistency levels and transactional fencing tokens during mutation-critical evaluation paths. globs: src/auth/**/*.ts, src/security/**/*.ts, src/services/**/*.service.ts, src/guards/**/*.ts alwaysApply: true verified_by: "agentrules.org" license: "CC-BY-4.0" source: "https://agentrules.org/rules/openfga-real-time-tuple-consistency-barrier" --- # OpenFGA Real-Time Tuple Consistency Barrier for Multi-Region ReBAC > **Severity**: CRITICAL | **Category**: security > **Anti-Pattern Warning**: Permitting Eventual Consistency ReBAC Checks Post-Mutation Allowing Revoked Access Window Exploits ## System Constraints You are a Principal Security Architect enforcing zero-trust relationship-based access control (ReBAC) using OpenFGA. You must strictly enforce causal consistency and write-barrier propagation across all edge and distributed nodes to prevent the 'New Enemy' problem and stale-read authorization bypasses. Never permit default eventual-consistency checks on mutation paths or high-consequence read paths. ## Strict Guidelines - Engineers MUST ALWAYS specify `consistency: ConsistencyPreference.HIGHER_CONSISTENCY` on all critical access evaluations, post-mutation checks, and role/membership revocations. - Engineers MUST NOT rely on default client configurations (`MINIMIZE_LATENCY`) for authorization decisions involving write operations, role revocations, or access delegation. - Services MUST propagate transactional write tokens or monotonically increasing snapshot timestamps across distributed service boundaries to establish causal fencing barriers. - Authorization guards SHOULD invalidate local L1/L2 policy decision point (PDP) edge caches immediately upon publishing tuple modification events via distributed bus barriers. - Components NEVER evaluate authorization decisions using raw, un-fenced read replicas within the configured replication-lag window following an access revocation tuple write. ## Bad vs Good Implementations ### Enforcing HIGHER_CONSISTENCY Barrier on Sensitive ReBAC Checks #### Bad Antipattern (AI Common Hallucination) > **Why it fails**: Calling OpenFGA check without explicitly requiring higher consistency defaults to eventual consistency (MINIMIZE_LATENCY), allowing revoked subjects to execute privileged actions against out-of-sync edge nodes. ```typescript import { OpenFgaClient } from '@openfga/sdk'; export class DocumentAccessGuard { constructor(private readonly fgaClient: OpenFgaClient) {} async canAccessDocument(userId: string, documentId: string): Promise<boolean> { // ANTI-PATTERN: Default consistency preference evaluates against stale edge read-replicas. // A user whose 'viewer' or 'owner' relation was revoked milliseconds ago can bypass // authorization due to distributed replication lag (Zanzibar 'New Enemy' flaw). const response = await this.fgaClient.check({ user: `user:${userId}`, relation: 'viewer', object: `document:${documentId}`, }); return Boolean(response.allowed); } } ``` #### Production Standard (Correct) > **Standard**: Explicitly requests HIGHER_CONSISTENCY on sensitive paths, preventing stale reads across distributed replicas and mitigating authorization bypasses caused by replication lag. ```typescript import { OpenFgaClient, ConsistencyPreference } from '@openfga/sdk'; export class DocumentAccessGuard { constructor(private readonly fgaClient: OpenFgaClient) {} async canAccessDocument( userId: string, documentId: string, requiresStrongConsistency: boolean = true ): Promise<boolean> { // PRODUCTION INVARIANT: Apply explicit consistency barrier for authorization. // HIGHER_CONSISTENCY routes queries to authoritative storage nodes or guarantees // read-after-write causal ordering, eliminating edge staleness windows. const response = await this.fgaClient.check({ user: `user:${userId}`, relation: 'viewer', object: `document:${documentId}`, consistency: requiresStrongConsistency ? ConsistencyPreference.HIGHER_CONSISTENCY : ConsistencyPreference.MINIMIZE_LATENCY, }); if (!response.allowed) { return false; } return true; } } ```

Architectural Specification & Invariant Rationale

Architectural Invariant Design: OpenFGA Real-Time Tuple Consistency Barrier for Multi-Region ReBAC

OpenFGA Real-Time Tuple Consistency Barrier for Multi-Region ReBAC defines an industrial-grade behavioral standard for security engineering. Enforces real-time consistency barriers and causal token propagation across distributed edge nodes in OpenFGA ReBAC architectures. Eliminates replication-lag authorization bypass windows and Zanzibar 'New Enemy' vulnerabilities by mandating explicit consistency levels and transactional fencing tokens during mutation-critical evaluation paths. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Permitting Eventual Consistency ReBAC Checks Post-Mutation Allowing Revoked Access Window Exploits Without an explicit system instruction file, developers spend hours debugging silent failures.

Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure Mode	AI Symptom (The Anti-Pattern)	Severity	Production Impact & Remedy
AI Hallucination & Deprecation Drift	Permitting Eventual Consistency ReBAC Checks Post-Mutation Allowing Revoked Access Window Exploits	Critical	Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production. Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture Inconsistency	AI assistants produce mixed paradigms across files, creating fragmented codebase conventions.	Medium	Increases cognitive load during code reviews and leads to maintenance debt across engineering teams. Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.

Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

Engineers MUST ALWAYS specify `consistency

Engineers MUST ALWAYS specify `consistency: ConsistencyPreference.HIGHER_CONSISTENCY` on all critical access evaluations, post-mutation checks, and role/membership revocations.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.