Check if an anonymous Supabase key can read a table via PostgREST by returning only the row count.
Check via PostgREST whether the anon key can read a table (row count only).
| Name | Required | Description | Default |
|---|---|---|---|
| op | No | select | |
| table | Yes |
Changes observed during successful MCP inspections.
v1.0.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It usefully discloses the transport (PostgREST) and that only a row count is returned, not the rows themselves, which tells the agent this is a read-only existence/visibility probe. However it says nothing about side effects, failure semantics, permissions required to run the probe, rate limits, or what a denial returns.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single tight sentence that front-loads the action and scoping constraint ('row count only') with no wasted words. Well sized for a two-parameter probe.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a simple probe with no output schema and no annotations, the core purpose is conveyed, but the undocumented 'op' parameter and the absence of any usage/alternative context leave gaps. It is adequate but not complete for correct invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema coverage is 0%, so the description should compensate, but it adds meaning only for the 'table' parameter (implicitly the target). The 'op' parameter, which defaults to 'select', is never mentioned in the description, leaving its allowed values and impact undocumented anywhere the agent can see.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb (check/probe) and resource (whether the anon key can read a table), with the mechanism (PostgREST) named. This is distinguishable from siblings like run_audit_query or get_schema, though it doesn't explicitly contrast itself with them.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
No guidance on when to use this versus run_audit_query or get_schema, and no stated prerequisites. Usage is only implied by the phrase 'whether the anon key can read a table', which suggests an access-control/RLS probe but leaves the triggering condition to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.