Look up a specific dataset and return detailed information about it. IMPORTANT: Always use this function before querying a new dataset to understand its required parameters and schema. The returned information includes: 1. Required parameters for the dataset (IMPORTANT for datasets like 'balances...
AI agents call lookup_dataset to retrieve information from Cryo MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
lookup_dataset performs information retrieval only—it queries metadata about datasets, their schemas, parameters, and examples. There are no side effects, data modifications, code execution, deletions, or financial operations. This is a classic Read category tool used for discovery and understanding before actual data queries are performed.
From the tool's definition Tool description states it 'Look up a specific dataset and return detailed information about it' with returned information being 'Required parameters', 'Schema details', and 'Example queries'.
Documented attack patterns abuse exactly the kind of access lookup_dataset gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Cryo MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for lookup_dataset:
{
"version": "1",
"default": "deny",
"tools": {
"lookup_dataset": {}
}
}lookup_dataset is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Look up a specific dataset and return detailed information about it. IMPORTANT: Always use this function before querying a new dataset to understand its required parameters and schema. The returned information includes: 1. Required parameters for the dataset (IMPORTANT for datasets like 'balances' that need an address) 2. Schema details showing available columns and data types 3. Example queries for the dataset When the dataset requires specific parameters like 'address' (for 'balances'), ALWAYS use the 'contract' parameter in query_dataset() to pass these values. Example: For 'balances' dataset, lookup_dataset('balances') will show it requires an 'address' parameter. You should then query it using: query_dataset('balances', blocks='1000:1010', contract='0x1234...') Args: name: The name of the dataset to look up sample_start_block: Optional start block for sample data (integer) sample_end_block: Optional end block for sample data (integer) use_latest_sample: If True, use the latest block for sample data sample_blocks_from_latest: Number of blocks before the latest to include in sample Returns: Detailed information about the dataset including schema and available fields. It is categorised as a Read tool in the Cryo MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Cryo MCP Server MCP server in PolicyLayer and add a rule for lookup_dataset: 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 Cryo MCP Server. Nothing to install.
lookup_dataset 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 lookup_dataset 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 lookup_dataset. 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.
lookup_dataset is provided by the Cryo MCP Server MCP server (z80dev/cryo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 10 Cryo MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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10 Cryo MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.