Get aggregated (not per wallet) smart trader and fund (EXCLUDES whales, large holders, influencers, etc.) token balances and 24h change per chain for all chains (default is ['all'], which queries all supported chains) or specific chain(s). Use filters to narrow down the results.
Part of the Nansen-MCP server.
Free to start. No card required.
AI agents call smart_traders_and_funds_token_balances to retrieve information from Nansen-MCP without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though smart_traders_and_funds_token_balances only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"smart_traders_and_funds_token_balances": {}
}
}See the full Nansen-MCP policy for all 24 tools.
These attack patterns abuse exactly the kind of access smart_traders_and_funds_token_balances gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Get aggregated (not per wallet) smart trader and fund (EXCLUDES whales, large holders, influencers, etc.) token balances and 24h change per chain for all chains (default is ['all'], which queries all supported chains) or specific chain(s). Use filters to narrow down the results.. It is categorised as a Read tool in the Nansen-MCP MCP Server, which means it retrieves data without modifying state.
Register the Nansen- MCP server in PolicyLayer and add a rule for smart_traders_and_funds_token_balances: 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 Nansen-MCP. Nothing to install.
smart_traders_and_funds_token_balances 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 smart_traders_and_funds_token_balances 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 smart_traders_and_funds_token_balances. 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.
smart_traders_and_funds_token_balances is provided by the Nansen- MCP server (nansen-ai/Nansen-MCP). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 24 Nansen-MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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