add_lookup_column · Fusebase MCP Server MCP: Risk & Policy

WHAT IT DOES

What add_lookup_column does on Fusebase MCP Server

AI agents use add_lookup_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_lookup_column needs a policy

While the lookup column itself is described as 'read-only' and does not modify existing data values, the act of adding a column to a database table is a Write operation that creates and modifies the database schema. This is reversible (the column can be removed), so it does not rise to Destructive level.

From the tool's definition Tool description states 'Add a Lookup column' which creates a new column structure in a database. This is a data modification operation that changes the schema of a table by adding a new lookup column.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_lookup_column Rate-limited

add_lookup_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_lookup_column": {
      "limits": [
        {
          "counter": "add_lookup_column_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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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_lookup_column

What does the add_lookup_column tool do? +

Add a Lookup column that displays data from a related table through an existing Relation column. The lookup column is read-only and automatically pulls data from the linked records. You must have an existing relation column first (created via add_relation_column). Use get_database_schema to find the relation column key. 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_lookup_column? +

Register the Fusebase MCP Server MCP server in PolicyLayer and add a rule for add_lookup_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_lookup_column? +

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

Can I rate-limit add_lookup_column? +

Yes. Add a rate_limit block to the add_lookup_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_lookup_column completely? +

Set action: deny in the PolicyLayer policy for add_lookup_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_lookup_column? +

add_lookup_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.