Guide
Prompt Injection Playbook for MCP Teams
A practical playbook for spotting, testing, and reducing prompt injection risk in MCP-enabled workflows.
Independent field guide June 6, 2026 For platform and security teams
Security guide
MCP security for teams that ship real agent systems
A clean operating guide for threat modeling MCP servers, narrowing tool access, and enforcing policy at the point where an agent tries to act.
Featured guide
MCP Security Review Checklist
A practical review framework for teams deciding whether an MCP server is ready for production use.
MCP Security
More guides
Guide
What Is MCP Security?
A practical overview of MCP security: the attack surface, the control stack, deployment models, and how to move from audit-only to enforcement in production.
Guide
McpVanguard vs Microsoft agent-governance-toolkit
A detailed comparison of two approaches to MCP security: McpVanguard's dedicated gateway vs Microsoft's framework-integrated SDK.
MCP Security
The MCP threat model
MCP turns integrations into callable tools. That is powerful, but it also means the agent can influence arguments, sequence actions, and cross boundaries that ordinary web controls were not designed to govern.
Unsafe tool invocation
Agents can pass risky arguments into tools that read files, execute code, send email, or modify infrastructure.
Prompt injection
Untrusted content can steer a model toward tool calls that the user, developer, or organization did not intend.
Over-broad permissions
A helpful integration becomes dangerous when one broad tool combines read, write, and execution behaviors.
Weak observability
Teams need durable logs of what was requested, why it was allowed, and what actually ran.
MCP Security
A practical control plan
Good MCP security is not one filter. It is a stack of narrow tools, explicit schemas, runtime validation, and audit trails that survive model mistakes.
Authenticate every boundary
Know which client, server, and tool principal is involved before permitting side effects.
Validate arguments
Treat model-generated arguments as untrusted input, especially for filesystem, network, and write operations.
Apply least privilege
Separate read tools from write tools and avoid generic shells or open database surfaces.
Record decisions
Log prompts, tool choices, arguments, policy decisions, and execution results.
MCP Security
Where governance belongs
Prompt instructions help, but production systems need deterministic checks between the model and the side effect. That is where execution governance becomes more than advice.
The enforcement layer should inspect the requested tool, arguments, identity, data sensitivity, and current policy before execution.
For high-risk tools, fail closed. If the request is ambiguous, malformed, or outside policy, the action should not run.
Next step
Move from advice to enforcement
McpVanguard adds deterministic policy checks around MCP tool execution so teams can govern what agents actually do.
Sources
References and further reading
Anthropic MCP overview
Background on why the protocol exists.
Official MCP docs
The canonical protocol reference.
OWASP GenAI Security
Broader risk framing for tool-rich AI systems.