hydra_update_preferences · Hydra Bridge MCP: Risk & Policy

WHAT IT DOES

What hydra_update_preferences does on Hydra Bridge

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

WHY IT NEEDS A POLICY

Why hydra_update_preferences needs a policy

This tool modifies user preferences reversibly—a Write operation. Severity is medium because preference changes affect the user's environment (themes, language, performance settings) but are not destructive and do not involve financial transactions or code execution.

From the tool's definition Tool name 'hydra_update_preferences' and description 'Update Hydra user preferences' indicate modification of user configuration settings.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

hydra_update_preferences Rate-limited

hydra_update_preferences 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": {
    "hydra_update_preferences": {
      "limits": [
        {
          "counter": "hydra_update_preferences_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about hydra_update_preferences

What does the hydra_update_preferences tool do? +

Update Hydra user preferences. It is categorised as a Write tool in the Hydra Bridge MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on hydra_update_preferences? +

Register the Hydra Bridge MCP server in PolicyLayer and add a rule for hydra_update_preferences: 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 Hydra Bridge. Nothing to install.

What risk level is hydra_update_preferences? +

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

Can I rate-limit hydra_update_preferences? +

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

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

hydra_update_preferences is provided by the Hydra Bridge MCP server (kleirrampage45/hydra-bridge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.