save_blob · BlobGuard MCP: Risk & Policy

WHAT IT DOES

What save_blob does on BlobGuard MCP

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

WHY IT NEEDS A POLICY

Why save_blob needs a policy

The tool creates or modifies data in a blob storage system. While the description is empty, the name and server context establish that this writes/stores blobs. It is reversible (Write, not Destructive) since blob storage systems typically allow overwriting.

From the tool's definition Tool name 'save_blob' and server context indicate storage of data; described as managing 'large code edits' and 'maintaining work integrity' in a multi-tenant blob storage system, suggesting persistent data modification.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

save_blob Rate-limited

save_blob 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": {
    "save_blob": {
      "limits": [
        {
          "counter": "save_blob_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 BlobGuard MCP, so you can run agents against it safely.

FAQ

Questions about save_blob

What does the save_blob tool do? +

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

How do I enforce a policy on save_blob? +

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

What risk level is save_blob? +

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

Can I rate-limit save_blob? +

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

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

save_blob is provided by the BlobGuard MCP server (voidious/blobguard-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.