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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavior: it never reads row data, it emits a single JSON value rather than a result set, and it must be executed externally via the Supabase SQL Editor or an execute_sql MCP tool. It stops short of noting practical execution limits (query runtime, result size, required privileges), which keeps it from a 5.

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?

It is front-loaded with the 'Use when' trigger and every clause carries a distinct fact (source of truth, what is read, what is excluded, return shape, how to run it, next tool). The first sentence is long and heavily parenthesized, which slightly hurts scannability, but there is no filler to cut.

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?

With zero parameters, no output schema and annotations covering the safety profile, the description supplies everything else an agent needs: why to choose it, what the SQL inspects and does not inspect, that the return is one JSON value, how to execute it, and where to send the result. Nothing material is missing.

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?

The tool takes zero parameters, so the baseline is 4. The description correctly implies there is nothing to configure — the SQL is generated as-is — and adds the meaningful invocation detail that execution happens outside this tool.

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?

The description states a specific verb and resource ('returns a read-only SQL query') and enumerates exactly what the query covers: RLS settings, anon/authenticated grants, policies, SECURITY DEFINER functions, storage buckets. It also draws the key boundary against the sibling workflow ('rather than migration files'), so an agent can distinguish it without opening any schema.

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?

It gives an explicit trigger ('Use when you need to check a live Supabase project rather than migration files'), the alternative it replaces, and the follow-up routing ('pass the JSON to deadbolt_check_supabase_access'). The agent knows both when to pick this tool and what to do with its output.

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