Subscribe to real-time blockchain events matching a filter expression.
AI agents call subscribe_events to retrieve information from Tenzro Ledger MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Subscribing to blockchain events is fundamentally a data retrieval operation with no side effects. The tool watches for and returns matching events but does not alter blockchain state, execute code, move funds, or modify any data. It falls clearly under the Read category with low severity since event subscription cannot be misused to cause damage to systems or data.
From the tool's definition Tool description states it 'Subscribe to real-time blockchain events matching a filter expression' — a read-only operation that retrieves event data without creating, modifying, deleting, or executing transactions.
Attacks that exploit this kind of access
Subscribe to real-time blockchain events matching a filter expression. It is categorised as a Read tool in the Tenzro Ledger MCP MCP Server, which means it retrieves data without modifying state.
Register the Tenzro Ledger MCP server in PolicyLayer and add a rule for subscribe_events: 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 Tenzro Ledger MCP. Nothing to install.
subscribe_events 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 subscribe_events 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 subscribe_events. 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.
subscribe_events is provided by the Tenzro Ledger MCP server (https://canton-mcp.tenzro.network/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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