capture_block · PicoScope MCP Server MCP: Risk & Policy

WHAT IT DOES

What capture_block does on PicoScope MCP Server

AI agents invoke capture_block to trigger actions in PicoScope MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why capture_block needs a policy

Capturing a block of data involves triggering a physical measurement operation on the PicoScope device, which is an external execution action rather than a simple read of already-existing data. It initiates hardware sampling, consumes device resources, and its effects depend on the current configuration (channel settings, trigger, etc.). This is best classified as Execute since it drives real-world hardware action.

From the tool's definition 'Capture a single block of data' — triggers an external hardware operation on the oscilloscope to acquire a waveform sample

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

capture_block Rate-limited

capture_block stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "capture_block": {
      "limits": [
        {
          "counter": "capture_block_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches PicoScope MCP Server, so you can run agents against it safely.

FAQ

Questions about capture_block

What does the capture_block tool do? +

Capture a single block of data. It is categorised as a Execute tool in the PicoScope MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on capture_block? +

Register the PicoScope MCP Server MCP server in PolicyLayer and add a rule for capture_block: 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 PicoScope MCP Server. Nothing to install.

What risk level is capture_block? +

capture_block is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit capture_block? +

Yes. Add a rate_limit block to the capture_block 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 capture_block completely? +

Set action: deny in the PolicyLayer policy for capture_block. 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 capture_block? +

capture_block is provided by the PicoScope MCP Server MCP server (markuskreitzer/picoscope_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.