Capture JS220 statistics at frequency_hz for duration_s. This is a frequency-based wrapper around measure_energy.
AI agents call capture_statistics to retrieve information from Joulescope without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool reads and retrieves measurement data from a precision energy analyzer. It has no side effects—it does not modify, delete, or execute external commands. The parameters (frequency_hz, duration_s) control sampling behavior but the fundamental operation is data retrieval. This is consistent with the 'Read' category for tools that query or retrieve data without side effects.
From the tool's definition Tool description states it 'captures' statistics and is 'a frequency-based wrapper around measure_energy'. The measure_energy tool (listed as sibling) retrieves energy measurements.
Attacks that exploit this kind of access
Capture JS220 statistics at frequency_hz for duration_s. This is a frequency-based wrapper around measure_energy. It is categorised as a Read tool in the Joulescope MCP Server, which means it retrieves data without modifying state.
Register the Joulescope MCP server in PolicyLayer and add a rule for capture_statistics: 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 Joulescope. Nothing to install.
capture_statistics 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 capture_statistics 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 capture_statistics. 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.
capture_statistics is provided by the Joulescope MCP server (juanqui/joulescope-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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