hash_length
Get number of fields in hash. Args: key: The name of the key Returns: Number of fields or error message
This record as markdown: /tools/aws/hash-length.md
What hash_length does on AWS
AI agents call hash_length 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 hash_length is rated Low
This is a read-only query operation that introspects a hash data structure to retrieve its field count. It has no side effects, cannot modify or delete data, and poses minimal security risk even if called with arbitrary keys.
From the tool's definition Tool returns 'Number of fields' with no modification capability. Accepts a key name and retrieves metadata about a hash structure. No data modification, deletion, or execution described.
Attacks that exploit this kind of access
The rule that runs hash_length 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 hash_length, this is the rule to start with:
hash_length 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 hash_length call is checked against it from then on.
Questions about hash_length
Get number of fields in hash. Args: key: The name of the key Returns: Number of fields 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 hash_length: 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.
hash_length 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 hash_length 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 hash_length. 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.
hash_length 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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