bitmap_count
Count the number of set bits (1) in a range. Args: key: The name of the bitmap key start: Start offset (inclusive, optional) end: End offset (inclusive, optional) Returns: Count of set bits or error message
This record as markdown: /tools/aws/bitmap-count.md
What bitmap_count does on AWS
AI agents call bitmap_count 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 bitmap_count is rated Low
This tool retrieves and counts data from a bitmap structure without creating, modifying, deleting, executing code, or triggering external operations. It is purely observational with minimal blast radius if misused by an AI agent—worst case, it could enumerate bitmap contents repeatedly, but poses no data loss or execution risk.
From the tool's definition Tool description explicitly states it 'Count[s] the number of set bits (1) in a range' with parameters for key, start, and end offsets. This is a read-only query operation on bitmap data with no modification or execution capability.
Attacks that exploit this kind of access
The rule that runs bitmap_count 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 bitmap_count, this is the rule to start with:
bitmap_count 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 bitmap_count call is checked against it from then on.
Questions about bitmap_count
Count the number of set bits (1) in a range. Args: key: The name of the bitmap key start: Start offset (inclusive, optional) end: End offset (inclusive, optional) Returns: Count of set bits 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 bitmap_count: 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.
bitmap_count 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 bitmap_count 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 bitmap_count. 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.
bitmap_count 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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