jsonb_index_suggest

THE RISK

Low Risk

Why jsonb_index_suggest needs a policy

This tool analyzes usage patterns and generates index suggestions—a read-only, informational operation that retrieves or queries data to produce recommendations. It does not create, modify, delete, or execute any database changes. The suggestion output has no side effects on the database itself.

From the tool's definition Tool name 'jsonb_index_suggest' and description 'Suggest indexes for JSONB columns based on usage patterns' indicate analysis and recommendation only. Verbs are 'suggest' and 'based on', with no mutations or execution of database modifications.

Documented attack patterns abuse exactly the kind of access jsonb_index_suggest gives an agent:

POLICY

How to control jsonb_index_suggest

PolicyLayer is an MCP gateway — it sits between your AI agents and Postgres Mcp Legacy, and nothing reaches the server without passing your rules. This is the rule we recommend for jsonb_index_suggest:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "jsonb_index_suggest": {}
  }
}

jsonb_index_suggest is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Postgres Mcp Legacy — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

Read tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about jsonb_index_suggest

What does the jsonb_index_suggest tool do? +

Suggest indexes for JSONB columns based on usage patterns. It is categorised as a Read tool in the Postgres Mcp Legacy MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on jsonb_index_suggest? +

Register the Postgres Mcp Legacy MCP server in PolicyLayer and add a rule for jsonb_index_suggest: 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 Postgres Mcp Legacy. Nothing to install.

What risk level is jsonb_index_suggest? +

jsonb_index_suggest is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit jsonb_index_suggest? +

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

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

jsonb_index_suggest is provided by the Postgres Mcp Legacy MCP server (neverinfamous/postgres-mcp-legacy). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Postgres Mcp Legacy tool call.

Start from Postgres Mcp Legacy, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →