AssumeRoleWithIdentityContext
AI agents call AssumeRoleWithIdentityContext as a supporting operation in AWS Lambda Tool MCP Server workflows.
The description is empty, which significantly lowers confidence. Based on the name alone, this tool likely calls AWS STS AssumeRole with an identity context, which is an authentication/authorization operation. It could be classified as Execute (triggering an external AWS API call) or Read (fetching temporary credentials), but without a description, certainty is low.
From the tool's definition Tool description is empty and uninformative; name 'AssumeRoleWithIdentityContext' suggests AWS STS role assumption with identity context
Documented attack patterns abuse exactly the kind of access AssumeRoleWithIdentityContext gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AWS Lambda Tool MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for AssumeRoleWithIdentityContext:
{
"version": "1",
"default": "deny",
"tools": {
"AssumeRoleWithIdentityContext": {
"limits": [
{
"counter": "assumerolewithidentitycontext_rate",
"window": "minute",
"max": 60,
"scope": "grant"
}
]
}
}
} AssumeRoleWithIdentityContext gets a rate cap, and everything else on the server is denied unless you say otherwise.
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AssumeRoleWithIdentityContext. It is categorised as a Other tool in the AWS Lambda Tool MCP Server MCP Server, which means it performs auxiliary operations.
Register the AWS Lambda Tool MCP Server MCP server in PolicyLayer and add a rule for AssumeRoleWithIdentityContext: 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 Lambda Tool MCP Server. Nothing to install.
AssumeRoleWithIdentityContext is a Other tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the AssumeRoleWithIdentityContext 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 AssumeRoleWithIdentityContext. 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.
AssumeRoleWithIdentityContext is provided by the AWS Lambda Tool MCP Server MCP server (awslabs.lambda-tool-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from AWS Lambda Tool MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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805 AWS Lambda Tool MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.