set_contains
Check if member exists in set. Args: key: The name of the key member: Member to check Returns: Boolean result or error message
This record as markdown: /tools/aws/set-contains.md
What set_contains does on AWS
AI agents call set_contains to retrieve information from AWS without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why set_contains is rated Low
This tool performs a membership check query on a set data structure. It only reads/queries data with no side effects, making it a Read operation with low severity.
From the tool's definition Check if member exists in set
Attacks that exploit this kind of access
The rule that runs set_contains 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 set_contains, this is the rule to start with:
set_contains is read-only, so it stays allowed. 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 set_contains call is checked against it from then on.
Questions about set_contains
Check if member exists in set. Args: key: The name of the key member: Member to check Returns: Boolean result or error message. It is categorised as a Read tool in the AWS MCP Server, which means it retrieves data without modifying state.
Register the AWS MCP server in PolicyLayer and add a rule for set_contains: 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.
set_contains is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the set_contains 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 set_contains. 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.
set_contains 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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