Nexus AI Security

Nexus Security Proxy

The Authorization Layer for
AI Agents

AI agents are now calling your tools, moving your data, and triggering real workflows. Nexus Security Proxy sits in front of your MCP servers to enforce policy-driven authorization, payload validation, and governance before any action is executed.

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Built for Model Context Protocol (MCP)
Policy-as-Code for AI & tools
Zero Trust for agent actions
< 25ms p95 authorization latency

The New Gap in AI Security

AI Agents Are the New Identity.
Who’s Authorizing Them?

We’ve learned how to secure users, devices, and applications. But AI agents don’t fit neatly into any of those categories:

They don’t sign in through Okta or Azure AD.
They don’t have HR records, onboarding, or offboarding.
Yet they can move money, query sensitive data, and call internal tools via MCP and APIs.
Most AI stacks today rely on basic checks:
What is Nexus Security Proxy?

A Gatekeeper for AI Agents and MCP Tool Calls

Nexus Security Proxy is a lightweight, high-performance gateway that sits in front of your Model Context Protocol (MCP) servers. It evaluates every request from AI agents and clients, then decides whether to:

ALLOW
The call proceeds normally.
DENY
The call is blocked immediately.
TRANSFORM
The payload is modified before execution.

Key Outcomes

Nexus brings Zero Trust principles to AI by treating every agent-to-tool call as an authorization decision.

Stop unauthorized tool calls
Enforce compliance on payloads
Centralize policy across MCP servers
Full visibility into AI actions

Designed for AI-Forward, Security-Critical Organizations

AI Platform & Engineering Teams

  • Safely expose internal tools to AI agents.
  • Standardize authorization logic instead of reinventing it in every MCP server.

Security & IAM Teams

  • Safely expose internal tools to AI agents.
  • Standardize authorization logic instead of reinventing it in every MCP server.

Risk, Compliance & Governance

  • Safely expose internal tools to AI agents.
  • Standardize authorization logic instead of reinventing it in every MCP server.

What Nexus Security Proxy Delivers

4.1 Policy-as-Code Authorization

Define policies in YAML or Rego

governs-box
policy

4.2 Payload-Aware Enforcement (ABAC)

Go beyond “who can call what” into “what can be sent”.

Capabilities

4.3 JSON Schema Validation

Nexus validates payloads against tool-specific JSON Schemas, rejecting malformed parameters to protect tools from injection.

4.4 Identity & Context-Aware

Integrates with JWTs, mTLS, or API keys. Extracts subject, roles, tenant, and environmental context (IP, region) for decisions.

4.5 Centralized Audit

Every decision (ALLOW/DENY) is logged with Who, What, Why, and Result. Exports directly to Splunk, Datadog, or ELK.

Built to Complement, Not Replace, Your MCP Servers

MCP servers manage tool definitions. Nexus manages authorization. It provides a single control layer across multiple servers and tools.

mcp-servers-design

Flexible Deployment for Modern AI Platforms

Reverse Proxy

Recommended to Start

Nexus terminates TLS and forwards to MCP server. Ideal for PoCs and rapid pilots.

Sidecar Mode

Recommended to Start

Nexus terminates TLS and forwards to MCP server. Ideal for PoCs and rapid pilots.

Service Mesh

Envoy / Istio

Nexus runs as an ext_authz service. Centralizes authorization across services and clusters.

Performance Targets

< 25ms
p95 Latency

10K+
RPS per instance

99.9%
Uptime (HA)

Real-World Scenarios Nexus Secures

Financial Transactions

Agents initiate payments or refunds. Nexus limits amounts, enforces dual-control for large transfers, and blocks unapproved accounts.

Sensitive Data Queries

Agents query customer records or health data. Nexus enforces which agents can see which datasets, and under what filters.

DevOps & Internal Tools

Agents trigger build or diagnostic tools. Nexus scopes which environments and commands are allowed from which agents.

Starting with Authorization.
Growing into Full AI Governance.

Near-Term Enhancements

  • Adaptive and context-based risk scoring
  • Optional step-up (MFA/Approval) for high-risk actions
  • Shadow mode for policy testing

Long-Term Vision

  • AI identity lifecycle management
  • Access reviews for AI agents
  • Behavior analytics & anomaly detection
  • Data boundary and DLP integrations

Why an Authorization Proxy is the Right Primitive

Instead of hardcoding RBAC and business rules into each MCP server, enterprises gain a shared control plane that can evolve as AI usage grows.

Decouples security policy from application logic
Scales with your AI adoption, not just a single project
Centralizes control across many servers and tools
Supports governance and compliance from day one

Frequently Asked Questions

We already have an MCP server with some RBAC. Why do we need this?
MCP RBAC is typically scoped to a single server and doesn’t handle payload policies, multi-environment governance, or centralized audit. Nexus gives you a cross-platform authorization fabric for all AI agents and servers.

Does this slow down our AI workloads?
Nexus is optimized for low-latency authorization. Policies are evaluated in-memory, with sub-25ms p95 targets, and the design is fully stateless for horizontal scaling.

Do we need to modify our AI agents or MCP servers?
In most cases, no. Nexus can run as a reverse proxy with no changes, making adoption quick and low-risk.

Secure Your AI Agents Before They Scale

AI is moving from experiments to production. Now is the time to put a real authorization layer in place—before agents gain access to critical systems without guardrails.

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