hydra_assign_collection · Hydra Bridge MCP: Risk & Policy

WHAT IT DOES

What hydra_assign_collection does on Hydra Bridge

AI agents use hydra_assign_collection 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_assign_collection needs a policy

The tool creates or updates relationships between games and collections, changing the organizational state of the library. This is a non-destructive modification that can be undone by reassigning or removing from collections. It does not execute code, delete data, or involve financial transactions, making Write the appropriate category.

From the tool's definition Tool description states 'Assign a game to one or more collections' — this modifies game metadata by assigning organizational tags/categories to games, which is a reversible write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

hydra_assign_collection Rate-limited

hydra_assign_collection 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_assign_collection": {
      "limits": [
        {
          "counter": "hydra_assign_collection_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_assign_collection

What does the hydra_assign_collection tool do? +

Assign a game to one or more collections. 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_assign_collection? +

Register the Hydra Bridge MCP server in PolicyLayer and add a rule for hydra_assign_collection: 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_assign_collection? +

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

Can I rate-limit hydra_assign_collection? +

Yes. Add a rate_limit block to the hydra_assign_collection 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_assign_collection completely? +

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

hydra_assign_collection 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.