write_register
A write tool on the Pypi:labmcp Alicat MCP server.
This record as markdown: /tools/lab-instrument-mcps/write-register.md
What write_register does on Pypi:labmcp Alicat
AI agents use write_register to create or update resources in Pypi:labmcp Alicat, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Pypi:labmcp Alicat environment.
Why write_register is rated Medium
Modbus write_register modifies register values in industrial/OT systems, which can affect physical equipment operation. This is reversible (Write, not Destructive) but carries medium severity due to potential industrial/safety implications if misused. Confidence reduced from high to 0.85 due to missing description details and lack of parameter documentation showing scope constraints.
From the tool's definition Tool name 'write_register' indicates write operation to Modbus registers. Sibling tools include 'read_coils' and 'read_input_registers' (Read category) and 'write_coil' (Write category), confirming this server manages industrial control/SCADA systems.
Attacks that exploit this kind of access
The rule that runs write_register safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Pypi:labmcp Alicat, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For write_register, this is the rule to start with:
write_register stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Pypi:labmcp Alicat, apply this rule, and every write_register call is checked against it from then on.
Questions about write_register
write_register is a write tool on the Pypi:labmcp Alicat MCP server. It is categorised as a Write tool in the Pypi:labmcp Alicat MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Pypi:labmcp Alicat MCP server in PolicyLayer and add a rule for write_register: 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 Pypi:labmcp Alicat. Nothing to install.
write_register is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the write_register 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 write_register. 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.
write_register is provided by the Pypi:labmcp Alicat MCP server (pypi:labmcp-alicat). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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