reg_write

Write registry value. Auto-selects client.

SERVERClaude C2 SOURCE0xyg3n/claude-c2

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/0xyg3n-claude-c2/reg-write.md

WHAT IT DOES

What reg_write does on Claude C2

AI agents use reg_write to create or update resources in Claude C2, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Claude C2 environment.

RISK

Why reg_write is rated Medium

Registry writes are reversible modifications to system configuration that can significantly impact system behavior, security settings, and application functionality. While not irreversible like deletion (Destructive) or involving financial transactions (Financial), and not executing arbitrary code (Execute), this is clearly a Write operation.

From the tool's definition Tool name is 'reg_write' with description 'Write registry value. Auto-selects client.' The function explicitly writes to Windows Registry, a critical system configuration store.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs reg_write safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Claude C2, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For reg_write, this is the rule to start with:

reg_write Rate-limited

reg_write 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "reg_write": {
      "limits": [
        {
          "counter": "reg_write_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Claude C2, apply this rule, and every reg_write call is checked against it from then on.

FAQ

Questions about reg_write

What does the reg_write tool do? +

Write registry value. Auto-selects client. It is categorised as a Write tool in the Claude C2 MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on reg_write? +

Register the Claude C2 MCP server in PolicyLayer and add a rule for reg_write: 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 Claude C2. Nothing to install.

What risk level is reg_write? +

reg_write is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit reg_write? +

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

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

reg_write is provided by the Claude C2 MCP server (0xyg3n/claude-c2). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

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team_manager_write_memory on Team Manager MCP → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →