add_relation_column · Fusebase MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_relation_column does on Fusebase MCP Server

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

WHY IT NEEDS A POLICY

Why add_relation_column needs a policy

This tool creates new database relations and columns, which are reversible write operations (relations can be removed, columns can be deleted). It does not execute arbitrary code or delete data, so it does not qualify as Execute or Destructive. It modifies data structures rather than merely reading them, so it exceeds Read category. There is no financial impact.

From the tool's definition Tool description explicitly states it 'creates a cross-database relation' and 'adds a lookup-source column' via POST request, indicating data modification operations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_relation_column Rate-limited

add_relation_column 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": {
    "add_relation_column": {
      "limits": [
        {
          "counter": "add_relation_column_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 Fusebase MCP Server, so you can run agents against it safely.

FAQ

Questions about add_relation_column

What does the add_relation_column tool do? +

Add a Relation column that links this database to another database table. This creates a cross-database relation (via POST /relations) and adds a lookup-source column. The column shows linked records from the target table. Use get_database_schema on the target table first to get its dashboardId and viewId. It is categorised as a Write tool in the Fusebase MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_relation_column? +

Register the Fusebase MCP Server MCP server in PolicyLayer and add a rule for add_relation_column: 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 Fusebase MCP Server. Nothing to install.

What risk level is add_relation_column? +

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

Can I rate-limit add_relation_column? +

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

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

add_relation_column is provided by the Fusebase MCP Server MCP server (ryan-haver/fusebase-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.