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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered. The description adds one genuinely useful behavioral fact not in the annotations: the cost of 10 credits per call. It does not clarify that the query is only parsed and not executed, nor does it describe output shape or latency, leaving a meaningful gap.

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?

The purpose is front-loaded, but the opening redundantly restates the tool name twice ('SQL Explainer: SQL Explainer...'), and the 'Perfect for...' sentence is marketing filler rather than operational guidance. The credit-cost note is worth its space; the rest could be trimmed.

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 two-parameter, single-purpose tool with a fully documented schema and an output schema, the description covers purpose, use cases, and cost adequately. The only notable omission is confirming that the query is not executed, which matters given openWorldHint=true.

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 description coverage is 100%, including an example query and a documented 'detail' parameter with its allowed levels, so the schema carries parameter meaning fully. The description adds nothing about either parameter, which is acceptable but earns only the baseline.

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 names a specific verb and resource: it 'analyzes SQL queries' and returns 'plain English explanations of what they do.' That is unambiguous, and no sibling tool covers SQL, so confusion risk is low. It stops short of an explicit contrast with alternatives, which keeps it at 4 rather than 5.

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?

'Perfect for learning SQL, code reviews, or documentation' gives implied use contexts rather than a when-to-use rule. There is no guidance on when not to use it, no alternative named, and no prerequisite stated (e.g., that the query need not be executable).

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