Topic

Security testing

7 articles on this topic from the NullSquare blog.

Claude

Anthropic’s Fourth Claude Incident: 7 AI Agent Containment Tests

September 10, 202610 min read

Anthropic’s Fourth Claude Incident: 7 AI Agent Containment Tests

Anthropic’s September 9 disclosure turns AI agent containment into a practical question: can you prove which actions your agent cannot take?

ClaudeAI security Agent security Security testingSandboxing

AI security

MCP security: threat model, risks, and production tests

August 28, 202614 min read

MCP security: threat model, risks, and production tests

A production-focused MCP security guide that turns tool poisoning, authorization, state, token, and runtime risks into explicit security boundaries and reproducible tests.

AI security Agent security Security testing Prompt injection

Agent security

AI agent memory needs its own security boundary

July 26, 20266 min read

AI agent memory needs its own security boundary

Persistent memory turns one hostile input into a cross-session risk. Secure the write, retrieval, action, and recovery paths as one system.

Agent security AI securityMemory poisoningPrompt injection Security testing

AI security

Persona is the hidden variable in agent behavior

July 4, 20264 min read

Persona is the hidden variable in agent behavior

NullSquare open-sourced Agent Behavior Lab so teams can measure how personas, tool definitions, histories, and model families shift agent safety.

AI security Prompt injection Agent security Model governance Security testing

AI security

Fable 5 is back. Coding agents just got harder to govern

July 4, 20266 min read

Fable 5 is back. Coding agents just got harder to govern

Anthropic restored Claude Fable 5 with tighter cyber classifiers and fallback routing. Here is what that means for coders, debuggers, and security teams.

AI security Agent security Model governance Developer ecosystems Security testing

AI security

GPT-6 restrictions could cost the U.S. the AI race

June 29, 20267 min read

GPT-6 restrictions could cost the U.S. the AI race

A data-backed argument for why blanket GPT-6 access restrictions would weaken U.S. AI leadership, and what targeted release gates should replace them.

AI securityAI policyModel governance Security testing Developer ecosystems

AI safety

The Fable ban is really a scope-control warning

June 20, 20263 min read

The Fable ban is really a scope-control warning

Anthropic Fable 5 showed the hard truth of frontier AI safety: stronger coding and bug-finding models are also stronger cyber systems.

AI safetyPrompt injectionCyber capabilityModel governance Security testing