fetch-balance · Lineage MCP Server MCP: Risk & Policy

WHAT IT DOES

What fetch-balance does on Lineage MCP Server

AI agents call fetch-balance to retrieve information from Lineage MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

WHY IT NEEDS A POLICY

Why fetch-balance needs a policy

This tool queries blockchain balance information, which is a read-only operation with no side effects. Even though the server handles sensitive operations like keypair generation, this specific tool merely retrieves balance data. The low severity reflects that misuse would only expose existing data, not modify state or move funds.

From the tool's definition Tool name 'fetch-balance' and server context describing 'balance queries' indicate data retrieval. Sibling tool 'get-balance' confirms this is a read operation. No description provided, but naming convention strongly suggests retrieval without modification.

Attacks that exploit this kind of access

Questions about fetch-balance

What does the fetch-balance tool do? +

fetch-balance. It is categorised as a Read tool in the Lineage MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on fetch-balance? +

Register the Lineage MCP Server MCP server in PolicyLayer and add a rule for fetch-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 Lineage MCP Server. Nothing to install.

What risk level is fetch-balance? +

fetch-balance is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit fetch-balance? +

Yes. Add a rate_limit block to the fetch-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.

How do I block fetch-balance completely? +

Set action: deny in the PolicyLayer policy for fetch-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.

What MCP server provides fetch-balance? +

fetch-balance is provided by the Lineage MCP Server MCP server (lineage-foundation/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.