TL;DR: AI agent communication protocols such as MCP and A2A standardise how agents exchange requests, but leave authorization, revocation, and consent largely to implementers, creating broad-token and stale-permission risks, according to Authzed. That gap means agentic systems can scale faster than their governance model, with least privilege and lifecycle control becoming the limiting factors.
NHIMG editorial — based on content published by Authzed: LLMjacking: How Attackers Hijack AI Using Compromised NHIs
By the numbers:
- 96% of technology professionals identify AI agents as a growing security threat, and 66% believe this risk is immediate.
- 80% of organisations report their AI agents have already performed actions beyond their intended scope, including accessing unauthorised systems, sharing sensitive data, and revealing access credentials.
Questions worth separating out
Q: How should security teams govern AI agent access when protocols leave authorization open-ended?
A: Treat authorization as a separate governance control rather than a protocol feature.
Q: Why do AI agents make least privilege harder to enforce than service accounts?
A: AI agents can change actions, tools, and delegation paths during execution, so a privilege set chosen at provisioning time may no longer match the task in progress.
Q: What breaks when revocation does not propagate across distributed agents?
A: Stale permissions continue to exist in caches, peers, or spawned sub-agents, so access that should have been removed remains usable.
Practitioner guidance
- Separate transport from authorization control. Define policy outside MCP, A2A, or ACP messages, then enforce it at a central decision point that can evaluate task, resource, and context before every sensitive action.
- Replace broad scopes with task-bound permissions. Issue tokens that map to a single task or object set, and reject delegated access that covers unrelated endpoints, resources, or write paths the agent does not need.
- Design revocation to propagate across the full agent graph. Test whether permission removal reaches cached agents, remote peers, and spawned sub-agents before the original task can continue, and treat failed propagation as a control defect.
What's in the full article
Authzed's full analysis covers the operational detail this post intentionally leaves for the source:
- Implementation patterns for granular token scoping across agent-to-tool and agent-to-agent flows.
- Comparative discussion of MCP, A2A, and ACP authorization gaps in distributed deployments.
- Examples of where revocation propagation breaks in asynchronous systems and cached peer state.
- Security design requirements for centralized authorization layers in agent infrastructure.
👉 Read Authzed's analysis of authorization gaps in AI agent communication protocols →
AI agent authorization is lagging behind protocol standardization?
Explore further
Authorization for agents is now a governance layer, not a token detail. The article correctly shows that protocol standardisation does not solve the core policy problem, because autonomous agents need scoped, revocable, context-aware permissions. For identity teams, the important shift is that agent communication standards and access governance are no longer separable design choices. Practitioners should treat authorization as an independent control plane for agentic behaviour.
A few things that frame the scale:
- 92% agree governing AI agents is critical to enterprise security, yet only 44% have implemented any policies to do so, according to AI Agents: The New Attack Surface report.
- Only 52% of companies can track and audit the data their AI agents access, leaving 48% with a complete blind spot for compliance and breach investigation.
A question worth separating out:
Q: Who is accountable when an AI agent shares data beyond its intended scope?
A: Accountability should sit with the team that defined the delegation boundary and the policy that allowed the handoff. If the system permits implied consent, broad scopes, or silent inheritance across agents, then the organisation owns the governance failure even if the individual action was taken by software. Audit trails need to show every approval boundary.
👉 Read our full editorial: Agent communication protocols leave authorization undefined for AI agents