AI agents call store.kv-get to retrieve information from Mcp without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves previously stored data from a key-value store. The function is purely read-only—it queries and returns data without modifying, creating, deleting, or executing anything. The pay-per-call USDC settlement mechanism is incidental to the tool's operation and does not change its fundamental nature as a data retrieval mechanism.
From the tool's definition Tool description explicitly states 'read back a JSON value you stored with store.kv-put', indicating a retrieval operation with no side effects.
Attacks that exploit this kind of access
STORE: read back a JSON value you stored with store.kv-put. It is categorised as a Read tool in the Mcp MCP Server, which means it retrieves data without modifying state.
Register the MCP server in PolicyLayer and add a rule for store.kv-get: 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 Mcp. Nothing to install.
store.kv-get 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 store.kv-get 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 store.kv-get. 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.
store.kv-get is provided by the MCP server (@2sio/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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