Returns a comma-separated list of all supported blockchain networks
AI agents call listSupportedChains to retrieve information from Chainlink Feeds without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a simple query operation that retrieves and returns information about supported blockchain networks. It has no side effects, does not execute code or commands, does not modify any data, and does not involve financial transactions. It is a straightforward informational lookup, which clearly falls under the Read category with low severity.
From the tool's definition The tool 'listSupportedChains' has a description stating it 'Returns a comma-separated list of all supported blockchain networks'. The verb 'Returns' indicates data retrieval with no modification or execution of operations.
Documented attack patterns abuse exactly the kind of access listSupportedChains gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Chainlink Feeds, and nothing reaches the server without passing your rules. This is the rule we recommend for listSupportedChains:
{
"version": "1",
"default": "deny",
"tools": {
"listSupportedChains": {}
}
}listSupportedChains is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Returns a comma-separated list of all supported blockchain networks. It is categorised as a Read tool in the Chainlink Feeds MCP Server, which means it retrieves data without modifying state.
Register the Chainlink Feeds MCP server in PolicyLayer and add a rule for listSupportedChains: 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 Chainlink Feeds. Nothing to install.
listSupportedChains 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 listSupportedChains 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 listSupportedChains. 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.
listSupportedChains is provided by the Chainlink Feeds MCP server (kukapay/chainlink-feeds-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Chainlink Feeds, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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5 Chainlink Feeds tools catalogued and risk-classified — across an index of 43,000+ MCP servers.