HCP Specification v2.0.0

1. Lifecycle Extension: RPI+C → RPI+V+C

v1.4.0: Research → Plan → Implement → Capture

v2.0.0: Research → Plan → Implement → Verify → Capture

Post-mortem analysis of 43 production projects identified that 68% of regressions occurred due to lack of formal verification between implementation and knowledge capture. The VERIFY state introduces verifiable contracts with mandatory functional and non-functional Quality Gates.

2. Active Constraints System

For sessions over 40k tokens, LLMs exhibit "attention decay". v2.0.0 introduces a Constraints Registry in .procontext/constraints/active-constraints.md and an automatic re-injection system for P0 (Critical) constraints every N turns.

Any P0 violation (e.g., secret leakage in logs, latencies) generates an "Incident" that blocks the pipeline and requires formal justification to be overridden.

3. Multi-Model Consensus

Active prevention against over-engineering bias (30% of projects) and under-engineering. A pre-implementation debate is structured using 3 differentiated roles: Architect (Optimist), Skeptic (Critic), and Synthesizer (Neutral) to generate Architectural Decisions with high empirical ROI.

4. Formal Invariants

• INV-01 (Verification): The transition from IMPLEMENT to CAPTURE must necessarily pass through VERIFY.
• INV-02 (Constraints): P0 constraints cannot be violated without explicit override (Technical Justification + Approval + Audit Log). Maps directly to EU AI Act Art. 14.
• INV-03 (Immutable Contracts): "Contract Snapshots" cannot be renegotiated mid-execution. If requirements change, the current scope is frozen and a new fork is created.