[P61] Depth Permission Gate: Hardware-Enforced Spawn-Depth Capability Restrictions for AI Agent Systems

Multi-agent AI systems spawn hierarchical agent populations where child agents inherit tasks from parents. Deep agent trees create security challenges: an agent at spawn depth 10 should not possess the same capabilities as a root orchestrator. Software-based permission enforcement adds measurable latency per check and remains vulnerable to kernel exploits and OS compromise. This document specifies a hardware permission gate that enforces spawn-depth-based capability restrictions in dedicated silicon. The depth permission gate (DPG) provides: (1) an agent context register storing agent identity and spawn depth with hardware protection; (2) a tier resolution circuit using combinational logic for single-cycle tier determination; (3) a permission matrix implemented as read-only memory for tier-operation lookups; (4) a gate decision circuit that blocks denied syscalls before kernel involvement; (5) an audit logging system with circular buffer and cryptographic signing; and (6) anti-tamper detection circuitry. Four permission tiers map to spawn depth ranges: FULL (depths 0-2) allows all operations; STANDARD (depths 3-5) blocks administrative operations; LIMITED (depths 6-8) allows only storage and LLM operations; MINIMAL (depths 9+) restricts to LLM inference only. Tier assignment is automatic from spawn depth alone, requiring no software configuration. The system supports at least 16,384 concurrent agents with permission checks completing in under 10 nanoseconds at 200 MHz. Permission inheritance ensures child permissions never exceed parent permissions through hardware-enforced mechanisms. Complete audit trails are maintained in tamper-resistant hardware with microsecond timestamp resolution.