VectorCertain LLC today announced the completion of manuscript-prep for The MYTHOS Playbook, a 34-chapter, 9-appendix technical reference designed for CISOs, security architects, and AI governance program leads operationalizing the new joint Five Eyes guidance on agentic AI security. The book closes its 17-sprint development cycle today and proceeds to June 2026 publication. A pre-order landing page is live at vectorcertain.com.
On May 1, 2026, six national cybersecurity agencies representing all five Five Eyes nations—CISA, NSA, Australia's ASD ACSC, the Canadian Centre for Cyber Security, NZ NCSC, and UK NCSC—jointly published "Careful Adoption of Agentic AI Services." This is the first coordinated multi-government security guidance specifically addressing agentic AI systems, moving autonomous-agent risk from "emerging vendor problem" to "critical national infrastructure" classification in a single 30-page document with 23 distinct risks and over 100 individual best practices.
The guidance identifies five risk classes: privilege, design and configuration, behavioral, structural, and accountability. It opens with the observation that "Agentic artificial intelligence (AI) systems increasingly operate across critical infrastructure and defense sectors and support mission-critical capabilities." It closes with explicit caution: "Until security practices, evaluation methods and standards mature, organisations should assume that agentic AI systems may behave unexpectedly and plan deployments accordingly, prioritising resilience, reversibility and risk containment over efficiency gains."
The market context the guidance enters is severe. Gartner projects AI agents will be embedded in 40% of enterprise applications by the end of 2026, up from less than 5% in 2025. One in eight enterprise breaches now involves AI agents—a 340% year-over-year increase, with 78% of compromised agents found to be over-permissioned. 88% of organizations report agent-related security incidents. Analysis of 18,470 production agent configurations found 98.9% lack deny rules entirely. The Centre for Long-Term Resilience documented 698 real-world AI deception incidents in a single six-month window—a 4.9x surge, including documented inter-model deception.
CISA Acting Director Nick Andersen framed the publication as a coordination signal: "CISA is committed to supporting the US's adoption of AI that includes ensuring it aligns with President Trump's Cyber Strategy for America and is cyber secure. We actively collaborate with government and international partners on shared priorities with AI advancements while addressing cybersecurity challenges and risks. CISA encourages agentic AI developers, vendors and operators to review this guide."
The MYTHOS Playbook fills the gap between policy intent and CISO-grade implementation. Every risk class identified in the Five Eyes joint guidance maps to specific MYTHOS Playbook chapters and appendices. Privilege risks map to Part II Architecture with patent-form least-privilege architecture across MRM-CFS-SG governance gates and the AGL-SG access governance layer. Design and configuration risks map to Part II and Part VI Deployment with secure-by-design patterns and a 12-clause vendor RFP language library at Appendix G. Behavioral risks map to Part III Vectors with a seven-vector behavioral threat taxonomy and Part IV Frameworks with statistical detection methodology including HOTS Homology (81.4% deception-detection precision). Structural risks map to Chapter 8's 8-2-8 compositional safety model and Part V SOC/Detection operations. Accountability risks map to Appendix F's GTID hash-chained audit record sample and Chapter 22's Crumpton 5/5 disclosure methodology.
The book's detection methodology rests on Clopper-Pearson exact binomial confidence intervals computed across 7,000 MYTHOS adversarial scenarios with 100% recall. Appendix C delivers a 119-cell cross-walk matrix mapping every Five Eyes risk class against NIST AI RMF, OWASP LLM Top 10, OWASP Agentic Top 10, CRI FS AI RMF, and MITRE ATLAS.
The manuscript was structurally complete by April 2026—before the Five Eyes joint guidance was published. The Playbook's 7-vector behavioral risk taxonomy was independently derived from real-world incident analysis. When the Five Eyes guidance was published, its five risk classes mapped cleanly onto the Playbook's existing structural commitments. No retrofit was required. This convergence is operationally significant: the risk taxonomy aligned because the underlying threat landscape is real and observable.
VectorCertain's SecureAgent platform has logged 14,208 internal trials across 38 techniques and 3 adversary profiles with zero failures, delivering a Technical Evaluation Score (TES) of 1.9636 out of 2.0 (98.2%) measured against MITRE's published TES methodology. MITRE ATT&CK Evaluations' Technical Lead Lex Crumpton confirmed in direct communication on April 8, 2026 that SecureAgent represents "a fundamentally different threat model" from post-execution detection—validating pre-execution AI governance as a new security category.
For CISOs and procurement teams asking "is this book aligned with the Five Eyes guidance," the answer is stronger than alignment: The MYTHOS Playbook is convergent independent confirmation of the Five Eyes risk model.
