Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add roedyrustam/vibes-plug --skill fga-rebac-authorization-expertgit clone --depth 1 https://github.com/roedyrustam/vibes-plugWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/roedyrustam/vibes-plug/fga-rebac-authorization-expert)<a href="https://agentmods.dev/skills/roedyrustam/vibes-plug/fga-rebac-authorization-expert"><img src="https://agentmods.dev/badge/skills/roedyrustam/vibes-plug/fga-rebac-authorization-expert/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/roedyrustam/vibes-plug/fga-rebac-authorization-expert"><img src="https://agentmods.dev/badge/skills/roedyrustam/vibes-plug/fga-rebac-authorization-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00073 | $0.03224 |
| Opus 5.5 | $0.00029 | $0.01290 |
| Sonnet 5.5 | $0.00015 | $0.00645 |
| Haiku 4.5 | $0.00007 | $0.00322 |
Grade A, and why
fga-rebac-authorization-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 285 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fine-Grained Authorization (FGA) & ReBAC Expert (2026 Zanzibar Edition)
English
Orchestration & Integration
- Identity & Authentication:
authentication-identity-expert,passkeys-webauthn-identity-expert,zero-trust-secret-vault - Multi-Tenant SaaS & Database:
saas-multi-tenant,database-orm-expert,supabase-security-expert - Permission-Aware AI & RAG:
vector-db-rag-expert,graph-rag-knowledge-expert,ai-safety-governance-expert - Formal Verification & Lifecycle:
formal-spec-z3-verifier,brainstorming,zero-to-prod-orchestrator,session-memory-manager
Description
Enterprise authorization engineering guide for Relationship-Based Access Control (ReBAC) modeled on Google Zanzibar (OpenFGA, SpiceDB, Permify) and attribute/policy engines (AWS Cedar, Cerbos). Moves beyond flat user.role === 'admin' checks to model nested organizational hierarchies (Organization -> Team -> Folder -> Document), sub-millisecond permission checks (Check(user, relation, object)), and Permission-Aware Vector RAG so AI agents never leak unauthorized documents across users.
Trigger Conditions
- Designing B2B SaaS permissions with nested inheritance (Workspace $\rightarrow$ Project $\rightarrow$ Document sharing).
- Integrating OpenFGA, SpiceDB, or AWS Cedar into API middlewares.
- Enforcing document-level access control on pgvector / RAG knowledge retrieval pipelines.
- Replacing brittle, deeply nested SQL permission joins with relationship tuples.
Authorization Paradigm Selection Matrix
| Paradigm | Engine Examples | Granularity | Best Use Case |
|---|---|---|---|
| RBAC (Role-Based) | Custom JWT claims, Clerk Org Roles | Coarse | Simple tenant roles (owner, admin, member) |
| ABAC (Attribute-Based) | AWS Cedar, Cerbos, OPA | Medium-High | Context rules (IP range, time window, department, spend limit) |
| ReBAC (Relationship-Based) | OpenFGA, SpiceDB (Zanzibar) | Ultra-Fine | Google Drive / Notion / Linear nested resource sharing & graphs |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday Changed · +138 lines fae84e4baa8a
- 2d ago First seen · 147 lines · 73 tokens per session scan A 2d48c898c0c8
fga-rebac-authorization-expert is a skill published in the GitHub repository roedyrustam/vibes-plug (113 stars, last pushed yesterday), licensed MIT. It adds 73 tokens to every session and 3,224 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-24.
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