hash_length | PolicyLayer

WHAT IT DOES

What hash_length does on Amazon Bedrock Knowledge Base Retrieval MCP Server

AI agents call hash_length to retrieve information from Amazon Bedrock Knowledge Base Retrieval MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

THE RISK

Low Risk

Why hash_length needs a policy

This is a simple query operation that returns a numeric property of an existing hash. It performs no write, delete, execute, or financial operations. The blast radius of misuse is negligible—an agent could at worst learn the size of internal hash structures, which is a minor information disclosure risk.

From the tool's definition Tool name is 'hash_length' and description states 'Get number of fields in hash' — it retrieves a count of fields in a hash data structure with no modification or side effects.

Documented attack patterns abuse exactly the kind of access hash_length gives an agent:

POLICY

How to control hash_length

PolicyLayer is an MCP gateway — it sits between your AI agents and Amazon Bedrock Knowledge Base Retrieval MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for hash_length:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "hash_length": {}
  }
}

hash_length is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Amazon Bedrock Knowledge Base Retrieval MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

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EXPLORE

Related tools and policies

More Amazon Bedrock Knowledge Base Retrieval MCP Server tools

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All 805 Amazon Bedrock Knowledge Base Retrieval MCP Server tools →

Read tools on other servers

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Go deeper

Roll out MCP under one policy → Per-person scoped tokens, one central policy, and full audit across every server your team connects.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about hash_length

What does the hash_length tool do? +

Get number of fields in hash. It is categorised as a Read tool in the Amazon Bedrock Knowledge Base Retrieval MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on hash_length? +

Register the Amazon Bedrock Knowledge Base Retrieval MCP Server 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 Amazon Bedrock Knowledge Base Retrieval MCP Server. Nothing to install.

What risk level is hash_length? +

hash_length is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit hash_length? +

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.

How do I block hash_length completely? +

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.

What MCP server provides hash_length? +

hash_length is provided by the Amazon Bedrock Knowledge Base Retrieval MCP Server MCP server (awslabs.bedrock-kb-retrieval-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Amazon Bedrock Knowledge Base Retrieval MCP Server tool call.

Start from Amazon Bedrock Knowledge Base Retrieval MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →

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805 Amazon Bedrock Knowledge Base Retrieval MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.