list_extensions

Lists all extensions in the database.

SERVERSupabase SOURCE@modelcontextprotocol/server-supabase

Low RISK CLASS

Category Read

Parameters 10 required

Recommended Allowedsee the rule below

Registry record Grade D, identity verified Pull the record →

This record as markdown: /tools/supabase/list-extensions.md

WHAT IT DOES

What list_extensions does on Supabase

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

Parameter	Type	Required	Description
`project_id`	string	—

Parameters from the server's own tool schema.

RISK

Why list_extensions is rated Low

This tool queries and returns information about database extensions without creating, modifying, or deleting any data. It is a pure Read operation with minimal blast radius if misused by an AI agent, as it only exposes metadata about available extensions.

From the tool's definition Tool name is 'list_extensions' and description states it 'Lists all extensions in the database' — a read-only retrieval operation with no side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs list_extensions safely

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

list_extensions Allowed

list_extensions 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": {
    "list_extensions": {}
  }
}

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

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

FAQ

Questions about list_extensions

What does the list_extensions tool do? +

Lists all extensions in the database. It is categorised as a Read tool in the Supabase MCP Server, which means it retrieves data without modifying state.

What parameters does list_extensions accept? +

list_extensions accepts 1 parameter: project_id. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on list_extensions? +

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

What risk level is list_extensions? +

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

Can I rate-limit list_extensions? +

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

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

list_extensions is provided by the Supabase MCP server (@modelcontextprotocol/server-supabase). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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