Compatible with every major AI agent and IDE
What is the Cerbos MCP Server?
Connect your Cerbos instance to any AI agent to manage complex authorization policies through natural language conversation.
What you can do
- Permission Evaluation — Use
check_resourcesto instantly verify if a principal can perform specific actions on resources based on your policies. - Query Planning — Generate AST-based query plans with
plan_resourcesto filter database results according to user permissions. - AuthZEN Compliance — Leverage standardized access requests using
authzen_evaluationandauthzen_evaluationstools. - System Monitoring — Check instance health and build metadata using
get_server_infoandget_authzen_config.
How it works
- Subscribe to this server
- Provide your Cerbos instance base URL (e.g.,
http://localhost:3592) - Start auditing and testing your access control logic directly from your chat interface
Who is this for?
- Software Engineers — debug complex RBAC/ABAC policies without manual API calls
- Security Auditors — verify permission logic across different roles and resource attributes
- DevOps Teams — monitor Cerbos instance metadata and configuration status
Built-in capabilities (6)
Single action evaluation using the AuthZEN entity model
Supports execute_all, deny_on_first_deny, and permit_on_first_permit semantics. Batch evaluation of multiple access requests using AuthZEN
This is a read-only evaluation. Evaluates permissions for a principal on a set of resources
Returns endpoint URLs for the AuthZEN APIs
Returns the version and build details of the Cerbos instance
Produces a query plan for obtaining a list of resources a principal is allowed to access
Why LlamaIndex?
LlamaIndex agents combine Cerbos tool responses with indexed documents for comprehensive, grounded answers. Connect 6 tools through Vinkius and query live data alongside vector stores and SQL databases in a single turn. ideal for hybrid search, data enrichment, and analytical workflows.
- —
Data-first architecture: LlamaIndex agents combine Cerbos tool responses with indexed documents for comprehensive, grounded answers
- —
Query pipeline framework lets you chain Cerbos tool calls with transformations, filters, and re-rankers in a typed pipeline
- —
Multi-source reasoning: agents can query Cerbos, a vector store, and a SQL database in a single turn and synthesize results
- —
Observability integrations show exactly what Cerbos tools were called, what data was returned, and how it influenced the final answer
Cerbos in LlamaIndex
Cerbos and 4,000+ other MCP servers. One platform. One governance layer.
Teams that connect Cerbos to LlamaIndex through Vinkius don't need to source, host, or maintain individual MCP servers. Every tool call runs inside a hardened runtime with credential isolation, DLP, and a signed audit chain.
Raw MCP | Vinkius | |
|---|---|---|
| Server catalog | Find and host yourself | 4,000+ managed |
| Infrastructure | Self-hosted | Sandboxed V8 isolates |
| Credential handling | Plaintext in config | Vault + runtime injection |
| Data loss prevention | None | Configurable DLP policies |
| Kill switch | None | Global instant shutdown |
| Financial circuit breakers | None | Per-server limits + alerts |
| Audit trail | None | Ed25519 signed logs |
| SIEM log streaming | None | Splunk, Datadog, Webhook |
| Honeytokens | None | Canary alerts on leak |
| Custom domains | Not applicable | DNS challenge verified |
| GDPR compliance | Manual effort | Automated purge + export |
Why teams choose Vinkius for Cerbos in LlamaIndex
The Cerbos MCP Server runs on Vinkius-managed infrastructure inside AWS — a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts. All 6 tools execute in hardened sandboxes optimized for native MCP execution.
Your AI agents in LlamaIndex only access the data you authorize, with DLP that blocks sensitive information from ever reaching the model, kill switch for instant shutdown, and up to 60% token savings. Enterprise-grade infrastructure, zero maintenance.

* Every MCP server runs on Vinkius-managed infrastructure inside AWS - a purpose-built runtime with per-request V8 isolates, Ed25519 signed audit chains, and sub-40ms cold starts optimized for native MCP execution. See our infrastructure
How Vinkius secures
Cerbos for LlamaIndex
Every tool call from LlamaIndex to the Cerbos MCP Server is protected by DLP redaction, cryptographic audit chains, V8 sandbox isolation, kill switch, and financial circuit breakers.
Frequently asked questions
Can I check if a specific user has permission to access a resource?
Yes. Use the check_resources tool by providing the principal (user) details and the resource information. The agent will return an evaluation of allowed or denied actions.
How do I generate a filter for my database based on user permissions?
Use the plan_resources tool. It produces a query plan (AST) that you can use to construct database queries, ensuring users only see records they are authorized to access.
Is it possible to verify the Cerbos server version via AI?
Yes, the get_server_info tool retrieves the version, build date, and commit hash of your connected Cerbos instance.
How does LlamaIndex connect to MCP servers?
Use the MCP client adapter to create a connection. LlamaIndex discovers all tools and wraps them as query engine tools compatible with any LlamaIndex agent.
Can I combine MCP tools with vector stores?
Yes. LlamaIndex agents can query Cerbos tools and vector store indexes in the same turn, combining real-time and embedded data for grounded responses.
Does LlamaIndex support async MCP calls?
Yes. LlamaIndex's async agent framework supports concurrent MCP tool calls for high-throughput data processing pipelines.
BasicMCPClient not found
Install: pip install llama-index-tools-mcp
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