Supabase Read-Only MCP Server

by rubenyh

Overview Schema Source Related Servers Discussions Admin

Python

Hybrid

Select Rows

select_rows

Retrieve bounded rows from allowlisted tables using typed filters, ordering, and paging, avoiding arbitrary SQL.

Instructions

Select bounded rows from an allowlisted object using typed filters, never arbitrary SQL.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "schema": "<schema>",
      "table": "<table>"
    },
    "name": "select_rows"
  }
}

Input Schema

Name	Required	Description	Default
`limit`	No
`table`	Yes
`offset`	No
`schema`	Yes
`columns`	No
`filters`	No
`order_by`	No

Output Schema

Name	Required	Description	Default
`ok`	Yes
`rows`	No
`error`	No
`limit`	Yes
`offset`	Yes
`row_count`	No
`truncated`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 12, 2026

TDQS

B3/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It does disclose meaningful behavioral traits: results are bounded, only allowlisted objects are reachable, filters are typed, and arbitrary SQL is rejected. However it omits what happens to defaults, permission/authorization errors, or how bounding interacts with limit/offset, leaving notable gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler; the core action and the key safety constraint appear immediately. It is on the terse side for a 7-parameter tool, but every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and the description correctly covers the read-only, bounded, allowlist-constrained nature of the call. But for a tool with seven parameters and no schema descriptions, the definition is thin on how filters, ordering, and pagination compose, leaving an agent to infer behavior.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% for seven parameters. The description only gestures at 'typed filters' and 'bounded rows', which maps loosely to the filters/limit parameters, but leaves schema, table, columns, offset, and order_by semantics to the raw schema. It does not compensate for the coverage gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb (Select) and resource (bounded rows from an allowlisted object), making the core operation unambiguous. It implicitly separates itself from siblings by emphasizing that it reads row data rather than metadata (list_allowed_tables, describe_table), though it never names those siblings explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It states the tool is for reading rows but offers no guidance on when to choose it over the sibling tools (e.g. against describe_table for schema inspection), nor any prerequisites like needing to call list_allowed_tables first. The usage context is implied at best.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server