pg_jsonb_agg

Aggregate rows into a JSONB array. With groupBy, returns all groups with their aggregated items.

SERVERPostgreSQL MCP Server SOURCE@neverinfamous/postgres-mcp

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/io-github-neverinfamous-postgres-mcp/pg-jsonb-agg.md

WHAT IT DOES

What pg_jsonb_agg does on PostgreSQL MCP Server

AI agents call pg_jsonb_agg to retrieve information from PostgreSQL MCP Server without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why pg_jsonb_agg is rated Low

The tool performs a read-only aggregation query that collects rows into JSONB format. It retrieves and transforms data but does not create, modify, delete, or execute arbitrary operations. The groupBy parameter controls the shape of results, not the underlying data. This is a standard database query operation with no side effects, placing it firmly in the Read category with low severity.

From the tool's definition "Aggregate rows into a JSONB array" — this is a data retrieval and aggregation operation that groups and formats existing data without modification, deletion, or execution of arbitrary code.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs pg_jsonb_agg safely

PolicyLayer is an MCP gateway: it sits between your AI agents and PostgreSQL MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For pg_jsonb_agg, this is the rule to start with:

pg_jsonb_agg Allowed

pg_jsonb_agg is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

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

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect PostgreSQL MCP Server, apply this rule, and every pg_jsonb_agg call is checked against it from then on.

FAQ

Questions about pg_jsonb_agg

What does the pg_jsonb_agg tool do? +

Aggregate rows into a JSONB array. With groupBy, returns all groups with their aggregated items. It is categorised as a Read tool in the PostgreSQL MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on pg_jsonb_agg? +

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

What risk level is pg_jsonb_agg? +

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

Can I rate-limit pg_jsonb_agg? +

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

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

pg_jsonb_agg is provided by the PostgreSQL MCP Server MCP server (@neverinfamous/postgres-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

What pg_jsonb_agg does on PostgreSQL MCP Server

Why pg_jsonb_agg is rated Low

The rule that runs pg_jsonb_agg safely

Questions about pg_jsonb_agg

More on PostgreSQL MCP Server, and thousands of servers like it.