Role Aware Hierarchical Context File System

Mapping agents to user identities and leveraging POSIX-style permissions combined with role-based context filtering can give you precise, secure control over what context each agent “sees.” This is especially important when you're exposing sensitive credentials (e.g. API keys or SSH certs).

Let’s break it down:

🔐 Agent as User | Role-Based Context Control via POSIX Permissions

1. Agents as POSIX Users or Service Accounts

Each AI agent is assigned a unique identity—like a “user” or service account—and optionally belongs to groups.
POSIX permissions (owner/group/other) or ACLs (Access Control Lists) dictate what filesystem paths each agent can read, write, or execute.
You can map these identities to MCP clients via OAuth or token-based authentication, so context access is always controlled per-agent (Playbooks, Model Context Protocol).

2. Role-Based Access Control (RBAC)

Roles (e.g. "CSS-tuner", "db-tuner", "devops") are mapped to agent identities.
Path-level access and context exposure are controlled based on roles. A CSS agent lacks permission to access /credentials/ or /deploy/production folders.
This aligns with classic RBAC: Permissions tied to roles, users assigned to roles (IARJSET).

3. Context-Aware / Attribute-Based Access Control (ABAC/PBAC)

You can extend RBAC with context-aware policies: time of day, agent trust score, project state, or current task scope.
For example, an agent gets elevated access for configuration files during runtime deployment sessions, but otherwise operates in a restricted sandbox (Tony Kipkemboi, WorkOS).

4. Graph-Based Access Control (ReBAC/GBAC)

If agents have more complex relationships—like delegation, hierarchical roles, or cross-project scopes—you can use graph-based policies.
GBAC lets you model agents, roles, context blobs, and paths as nodes in a graph, and define dynamic rules based on attributes and relationships (Wikipedia).

🗂️ How This Could Work in Your HCFS + MCP Server

A. Filesystem Interface (FUSE + MCP)

Expose POSIX-style file operations: readFile, listDir, etc., subject to permission enforcement.
Under the hood, operations map to context blobs linked by path metadata.
Each agent is authenticated as a user; permissions at the FS level enforce role-based allowances.

B. Authorization Engine

Use a policy engine (e.g. Cerbos, OPA) to evaluate permissions dynamically based on agent roles, path, context attributes, and real‑time factors (cerbos.dev, cerbos.dev, Cloud Security Alliance).

Example:

Allow CSS-agent to read /projects/website/css/*
Deny CSS-agent to read /credentials/* or /deploy/prod/*

You can implement ABAC rules like:
- “Allow read if agent.role == ‘devops’ AND time in deploy window”
- “Allow context subscribe only if task = 'analytics' AND trust_score > threshold.”

C. Auditing & Lifecycle

Every context access is logged with agent ID, role, timestamp, and path info.
Supports revocation (role removal), role transitions, and temporary escalation via just-in-time tokens (e.g. via OAuth scope grants) (Magai).

🧠 Context-Aware Role Segmentation: Why It Matters

Minimize attack surface: Agents only see what they need—no risk of leaking keys or tuning internal modules.
Operational clarity: Each agent’s domain and context exposure is explicit, auditable, and explainable.
Scalability: Adding new agents/roles doesn’t require rewriting FS or context logic—just update the permission policies.

📋 Summary Table

Capability	Approach
Agent identity & grouping	Map agents to POSIX users/groups
Path-level access control	POSIX permissions or ACLs on FS subtree
Role-based visibility	RBAC policies controlling read/write of context blobs
Dynamic access context	ABAC/PBAC based on agent role, task, trust, time
Complex relationships	Graph-based access (GBAC/ReBAC) for cross-role semantics
Auditing & revocation	Authentication/auth logs and just-in-time role change

🛠️ Example: CSS Agent vs DevOps Agent

CSS Agent (css-tuner role):
- Access: /projects/site/css/**, /projects/site/html/**
- No access: /deploy/**, /credentials/**, /api_keys/**
DevOps Agent (devops role):
- Access: Everything except /source-code/experimental/* if not authorized.
- Elevated access during deploy operations (time-bound via ABAC).

📝 Suggested Implementation Stack

FUSE layer backed by MCP endpoints, enforcing path-based checks.
Policy engine: Cerbos or OPA for RBAC/ABAC logic (cerbos.dev, Model Context Protocol, Playbooks, HackerNoon, WorkOS).
Authentication: OAuth flows via MCP; agents get scoped tokens with role claims (stytch.com).
Graph-based augmentation: If you need delegation or inheritances, build path and agent relationship graph (e.g. Neo4j + policy engine referencing it).

✅ In Conclusion

Mapping agents to users/groups with POSIX semantics and augmenting with role-based AND context-aware access control is not only valid but strongly practical. It lets you control who sees what context, prevent sensitive blob exposure, and maintain flexible, secure context-sharing for agentic multi-agent environments.

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