Security Model

How the layers fit together

A2AWall adds layered controls around standard A2A transport and discovery.

Architecture

Architecture diagram for A2AWall.

1. Gateway admission control

Requests are admitted or rejected based on identity, capability, scopes, trust tier, approvals, and message-size limits.

2. Trusted context boundary

System and developer instructions remain privileged. User, retrieval, memory, tool, and peer-agent content are treated as reference unless explicitly trusted by policy.

3. Secure runtime and tools

Tool execution should pass through action validation and sandbox policy before it touches files, networks, APIs, or delegated agents.

4. Memory and retrieval controls

Memory writes are source-aware and tenant-aware. Retrieved documents are classified as allow, reference-only, or quarantine.

5. Delegation controls

Delegation depth, fan-out, capability allowlists, and trust thresholds constrain multi-agent blast radius.