This record as markdown: /tools/aws/simulate-principal-policy.md
What simulate_principal_policy does on AWS
AI agents invoke simulate_principal_policy to trigger actions in AWS. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why simulate_principal_policy is rated High
The tool name strongly suggests it simulates IAM principal policy evaluation (analogous to AWS IAM SimulatePrincipalPolicy API), which runs a simulation/execution of policy authorization checks against a principal. This is an Execute-category action as it triggers an evaluation/simulation engine.
From the tool's definition Tool name: 'simulate_principal_policy' — no description provided
Attacks that exploit this kind of access
The rule that runs simulate_principal_policy safely
PolicyLayer is an MCP gateway: it sits between your AI agents and AWS, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For simulate_principal_policy, this is the rule to start with:
simulate_principal_policy stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect AWS, apply this rule, and every simulate_principal_policy call is checked against it from then on.
Questions about simulate_principal_policy
simulate_principal_policy is a execute tool on the AWS MCP server. It is categorised as a Execute tool in the AWS MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the AWS MCP server in PolicyLayer and add a rule for simulate_principal_policy: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches AWS. Nothing to install.
simulate_principal_policy is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the simulate_principal_policy rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for simulate_principal_policy. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
simulate_principal_policy is provided by the AWS MCP server (@awslabs/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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