Returns native gas token and major stablecoin balances for any EVM or Solana address across supported chains, reading directly from on-chain RPC with no third-party indexer dependency. Accepts an EVM 0x-address (queries Ethereum, Arbitrum, Base, BNB Chain, and Optimism) or a Solana base58 pubkey ...
Part of the Syenite server.
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AI agents call wallet.balances to retrieve information from Syenite 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 wallet.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": {
"wallet.balances": {}
}
}See the full Syenite policy for all 46 tools.
These attack patterns abuse exactly the kind of access wallet.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.
Returns native gas token and major stablecoin balances for any EVM or Solana address across supported chains, reading directly from on-chain RPC with no third-party indexer dependency. Accepts an EVM 0x-address (queries Ethereum, Arbitrum, Base, BNB Chain, and Optimism) or a Solana base58 pubkey (queries native SOL and all non-zero SPL token accounts) — address format is detected automatically. Optionally pass chains to restrict the query to specific chains and reduce latency. Use this before executing swaps, bridges, or lending operations to confirm the wallet holds sufficient funds. Returns balances per chain with raw and human-readable amounts; chains with RPC errors are included with an error marker rather than silently dropped.. It is categorised as a Read tool in the Syenite MCP Server, which means it retrieves data without modifying state.
Register the Syenite MCP server in PolicyLayer and add a rule for wallet.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 Syenite. Nothing to install.
wallet.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 wallet.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 wallet.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.
wallet.balances is provided by the Syenite MCP server (@syenite/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 46 Syenite tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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