update_bucket_labels · Storage MCP: Risk & Policy

WHAT IT DOES

What update_bucket_labels does on Storage

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

WHY IT NEEDS A POLICY

Why update_bucket_labels needs a policy

The tool modifies bucket labels, which are metadata attributes in GCS. This is a Write operation because it creates or modifies data reversibly. The severity is medium because mislabeling buckets could lead to misconfiguration, access control confusion, or operational errors, but the change is reversible and does not directly impact data integrity or financial systems.

From the tool's definition Tool name 'update_bucket_labels' combined with description 'Updates labels for a bucket' indicates modification of bucket metadata. Labels are reversible configuration changes that do not delete or overwrite core data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_bucket_labels Rate-limited

update_bucket_labels 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": {
    "update_bucket_labels": {
      "limits": [
        {
          "counter": "update_bucket_labels_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 Storage, so you can run agents against it safely.

FAQ

Questions about update_bucket_labels

What does the update_bucket_labels tool do? +

Updates labels for a bucket. It is categorised as a Write tool in the Storage MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on update_bucket_labels? +

Register the Storage MCP server in PolicyLayer and add a rule for update_bucket_labels: 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 Storage. Nothing to install.

What risk level is update_bucket_labels? +

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

Can I rate-limit update_bucket_labels? +

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

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

update_bucket_labels is provided by the Storage MCP server (@google-cloud/storage-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.