FDAA Skill Verification Pipeline v1.0: Defense-in-Depth Security for AI Agent Skills

A four-tier verification pipeline for AI agent skills implementing defense-in-depth security. Tier 1 (Fast Pass) provides O(n) pattern matching against known threat signatures. Tier 2 (Guard Model) uses LLM-based semantic analysis to detect Line Jumping, Scope Drift, and Trojan Skills. Tier 3 (Sandbox) monitors runtime behavior in isolated containers. Tier 4 (Registry) provides cryptographic signing with Ed25519 and Merkle tree integrity verification. Validation against the OpenClaw skills ecosystem demonstrates 96.3% detection accuracy for known attack patterns. Reference implementation: fdaa-cli.