Get a block by number
AI agents call get_block_by_number to retrieve information from Sperax Ecosystem Crypto & DeFI MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical blockchain data (a specific block by its number). It has no side effects, does not execute code or transactions, does not modify state, and does not involve financial transactions. It is a straightforward data retrieval operation typical of blockchain RPC calls, making it a Read category tool with low severity risk.
From the tool's definition Tool name 'get_block_by_number' and description 'Get a block by number' indicate a read-only query operation that retrieves blockchain block data without modification or execution of transactions.
Documented attack patterns abuse exactly the kind of access get_block_by_number gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Sperax Ecosystem Crypto & DeFI MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for get_block_by_number:
{
"version": "1",
"default": "deny",
"tools": {
"get_block_by_number": {}
}
} get_block_by_number is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get a block by number. It is categorised as a Read tool in the Sperax Ecosystem Crypto & DeFI MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Sperax Ecosystem Crypto & DeFI MCP Server MCP server in PolicyLayer and add a rule for get_block_by_number: 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 Sperax Ecosystem Crypto & DeFI MCP Server. Nothing to install.
get_block_by_number 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 get_block_by_number 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 get_block_by_number. 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.
get_block_by_number is provided by the Sperax Ecosystem Crypto & DeFI MCP Server MCP server (sperax/sperax-crypto-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Sperax Ecosystem Crypto & DeFI 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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1318 Sperax Ecosystem Crypto & DeFI MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.