AI Defense Stack

Agent & MCP security

Lasso MCP Gateway: open-source plugin gateway for MCP servers

Lasso MCP Gateway is an open-source plugin gateway for MCP servers from Lasso Security. It is released under the MIT license and is offered as: Self-hosted, CLI.

  • Last reviewed
Visit Lasso MCP Gateway (opens in a new tab) Documentation (opens in a new tab) Source code (opens in a new tab)
Open sourceMIT Layer 7: Agent and tool access

Best for

Developers who want one self-hosted gateway in front of several MCP servers, with plugins they can add or swap

Consider instead if

  • You want a wrapper that pins each server's approved setup and quarantines flagged responses locally. See mcp-context-protector.

What Lasso MCP Gateway does

Lasso MCP Gateway is an open-source (MIT) gateway that sits between an LLM agent and other MCP servers. It reads server definitions from an mcp.json file, manages those servers and intercepts requests and responses so plugins can act on them. Plugins can mask secrets, mask personal data through Microsoft Presidio, trace tool calls to logs, SQLite or DuckDB, and, with a Lasso API key, send content to Lasso's API for prompt injection, PII, custom policy and harmful content checks. A scan option checks MCP server reputation and tool descriptions before loading and can block risky servers. You run it with pip or Docker. The latest GitHub release is from January 2026.

This summary is our own wording of the sourced facts on this page.

Key facts

Each value links to the page that states it, with the date we checked it.

Vendor
Lasso Security Source, checked October 21, 2026: github.com (opens in a new tab)
Status
Active Source, checked October 21, 2026: api.github.com (opens in a new tab)
Open source
Yes: MIT Source, checked October 21, 2026: github.com (opens in a new tab)
Repository
github.com Source, checked October 21, 2026: github.com (opens in a new tab)
GitHub stars
396 as of October 21, 2026 Source, checked October 21, 2026: api.github.com (opens in a new tab)
Latest push
January 22, 2026 Source, checked October 21, 2026: api.github.com (opens in a new tab)
Latest release
January 21, 2026 Source, checked October 21, 2026: api.github.com (opens in a new tab)
Deployment
Self-hosted, CLI Source, checked October 21, 2026: github.com (opens in a new tab)
Pricing model
Free Source, checked October 21, 2026: github.com (opens in a new tab)
Website
github.com Source, checked October 21, 2026: github.com (opens in a new tab)
Documentation
github.com Source, checked October 21, 2026: github.com (opens in a new tab)
API reference
Not documented in the sources we checked
Quickstart
github.com Source, checked October 21, 2026: github.com (opens in a new tab)
Security page
Not documented in the sources we checked
Attestations or disclosure
Not documented in the sources we checked

Capabilities

As documented by the vendor or project. The tag is our label from a controlled vocabulary.

Integrations

Where Lasso MCP Gateway fits in our AI security layers

Our analysis

Our editorial model, not a standard. The primary layer follows the category, except for tools whose main documented job is detection and response; other layers rest on a capability the sources document. How the model works.

AI security layers that Lasso MCP Gateway covers, with the role, how each applies and what it rests on
LayerRoleHow it appliesBased on
L7 Agent access Agent and tool access Primary Limit which tools, MCP servers, data and credentials an agent can use, and require approval for risky actions. Follows its category, Agent & MCP security
L3 Supply chain Model and supply chain Also covers Documents checks of server reputation and tool descriptions before loading. Scan option checks MCP server reputation and tool descriptions before loading and can block risky servers
L6 Runtime Runtime guardrails Also covers Documents prompt injection checks on content that passes through the gateway. The lasso plugin sends content to Lasso's API to check for prompt injection, among other risks, and needs a Lasso API key

OWASP LLM Top 10 mapping

Our analysis

The risk list is OWASP's (Top 10 for LLM Applications, 2025). The mapping is our analysis, and each row rests on a capability the sources document.

OWASP LLM risks mapped to Lasso MCP Gateway, with the capabilities each mapping rests on
RiskHow it appliesBased on
LLM01 Prompt Injection The lasso plugin checks content for prompt injection, using Lasso's API and a Lasso API key. The lasso plugin sends content to Lasso's API to check for prompt injection, among other risks, and needs a Lasso API key
LLM03 Supply Chain The scan option checks MCP server reputation and tool descriptions before servers are loaded. Scan option checks MCP server reputation and tool descriptions before loading and can block risky servers

Not mapped in our analysis: LLM02, LLM05, LLM06, LLM07. These are risks we expect tools in this category to cover; the sources we checked do not document a matching capability.

Alternatives and related tools

More in Agent & MCP security, ranked within the category by Coverage Score.

Cisco DefenseClaw

Cisco

Open sourceApache-2.0
  • CLI
  • Self-hosted

Scans skills and MCP servers, inspects agent tool calls and keeps an audit trail around AI coding agents.

Best for: Security teams that want scanning, guardrails and an audit trail around the coding agents developers already run, starting in observe mode before anything is blocked

Coverage Score 76 out of 100
  • LLM01 Prompt Injection
  • LLM02 Sensitive Information Disclosure
  • LLM06 Excessive Agency

Reviewed

Docker MCP Gateway

Docker

Open sourceMIT
  • CLI
  • Self-hosted

Proxies AI clients to MCP servers it runs as isolated Docker containers, with tool filters and call logs.

Best for: Developers and platform teams that already use Docker and want MCP servers to run in containers behind one gateway with per-server tool selection

Coverage Score 72 out of 100
  • LLM02 Sensitive Information Disclosure
  • LLM06 Excessive Agency

Reviewed

agentgateway

agentgateway (a Series of LF Projects, LLC)

Open sourceApache-2.0
  • CLI
  • Self-hosted
  • Cloud-native

Open-source proxy that applies auth, CEL policy and guardrails to LLM, MCP and agent-to-agent traffic.

Best for: Platform teams that want one open-source gateway in front of MCP servers and LLM providers, with token validation, CEL rules per MCP method and pluggable guardrails

Coverage Score 69 out of 100
  • LLM02 Sensitive Information Disclosure
  • LLM06 Excessive Agency

Reviewed

Lasso MCP Gateway FAQ

Is Lasso MCP Gateway open source?

Yes. It is released under the MIT license, and the code is on GitHub at lasso-security/mcp-gateway.

Do I need a Lasso account?

Only for the lasso plugin, which needs a LASSO_API_KEY from signing up with Lasso Security. The basic, presidio and xetrack plugins are described without that requirement.

How do you run it?

Install it with pip install mcp-gateway and start it with the --mcp-json-path and --plugin flags, or build the Docker image from the repository.

Key facts you can cite

We have no commercial relationship with Lasso Security.

Sources & last reviewed

Last reviewed . We compile from the vendors' own public pages and repositories and we do not run the products. Source links open in a new tab. Found a mistake? Report a correction.