Refund shares from a CANCELLED market at cost basis. If num_shares is omitted, the tool refunds your full position for the selected outcome. Amounts in responses are micro-USDC (1 USDC = 1,000,000).
AI agents use refund_shares to commit financial operations through Question Market — usually the final step of a payment, billing, or trading workflow. A call moves real money.
The tool triggers an on-chain financial transaction that transfers USDC tokens to the user in exchange for shares in a cancelled prediction market. This is a financial redemption/refund operation involving real assets on the Algorand blockchain. Misuse or misconfiguration could result in unintended asset movements, warranting high severity.
From the tool's definition 'Refund shares from a CANCELLED market at cost basis' — this moves money (USDC on Algorand) back to the user by redeeming shares for their cost basis value, constituting a financial transaction on a prediction market platform.
Attacks that exploit this kind of access
Refund shares from a CANCELLED market at cost basis. If num_shares is omitted, the tool refunds your full position for the selected outcome. Amounts in responses are micro-USDC (1 USDC = 1,000,000). It is categorised as a Financial tool in the Question Market MCP Server, which means it involves financial transactions. Block by default and require explicit approval.
Register the Question Market MCP server in PolicyLayer and add a rule for refund_shares: 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 Question Market. Nothing to install.
refund_shares is a Financial tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the refund_shares 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 refund_shares. 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.
refund_shares is provided by the Question Market MCP server (qmrkt/mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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