Analysis · curated 27 Jun 2026
Inside MCP: defending the runtime layer of agent security · Arcis Blog
First reported arcis-website.pages.dev
Coverage timeline
Single-source analysis — first reported, latest, and curated coincide.
Why it matters
Defenders need controls that can actually refuse malicious tool calls at runtime, not just detect them after the fact, especially as MCP tool-call abuse becomes a real attack surface.
An Arcis blog post argues that agent security has four layers (identity, pre-deploy testing, observability, runtime defense) and that the runtime hot path is structurally underserved. It frames MCP's explicit tool-call contract as enabling runtime defense against agent toolcall injection (their vector V32), applying allowlist/sanitize/refuse techniques at the agent-tool boundary.