write_object · Observability MCP: Risk & Policy

WHAT IT DOES

What write_object does on Observability

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

WHY IT NEEDS A POLICY

Why write_object needs a policy

The tool creates or modifies data in a GCP bucket (reversible operation). While write operations carry risk in cloud storage contexts due to potential data overwrite or quota impacts, the action is not irreversible (objects can be versioned or deleted) and does not destroy existing data by definition.

From the tool's definition Tool name is 'write_object' and description states it 'Writes a new object to the bucket.' This is an explicit data creation operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

write_object Rate-limited

write_object 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": {
    "write_object": {
      "limits": [
        {
          "counter": "write_object_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 Observability, so you can run agents against it safely.

FAQ

Questions about write_object

What does the write_object tool do? +

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

How do I enforce a policy on write_object? +

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

What risk level is write_object? +

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

Can I rate-limit write_object? +

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

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

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