AI agents call get_sol_balance to retrieve information from Onchain without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves account balance data without modifying state or triggering external actions. It is a straightforward read operation with minimal blast radius if misused by an AI agent — worst case being unauthorized access to publicly queryable blockchain data.
From the tool's definition Tool description explicitly states 'Get the native SOL balance' — a pure query operation. Server description confirms 'read-only access' and 'natural language queries'. No side effects, modifications, or external operations.
Attacks that exploit this kind of access
Get the native SOL balance of a Solana account. It is categorised as a Read tool in the Onchain MCP Server, which means it retrieves data without modifying state.
Register the Onchain MCP server in PolicyLayer and add a rule for get_sol_balance: 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 Onchain. Nothing to install.
get_sol_balance 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_sol_balance 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_sol_balance. 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_sol_balance is provided by the Onchain MCP server (sylvainlondon136/onchain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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