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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld, so the safety profile is covered. The description adds real context beyond that by specifying the exact fields returned and the supported engines (postgres, mysql, mariadb, sqlite). It omits auth/permission requirements and behavior on an unknown host or table.

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?

Three short sentences, front-loaded with the purpose and return contents before the usage instruction. The closing engine sentence is largely redundant with the schema enum, which is the only wasted clause.

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?

There is no output schema, so the description correctly carries the burden of explaining what comes back, and it does so thoroughly. Coverage of failure modes (bad host, missing table, insufficient permissions) is absent, but nothing essential to calling the tool correctly 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?

Schema description coverage is 100%, so every parameter including the engine enum and the sqlite file-path note is already documented in the schema. The description's only parameter-relevant content is the engine list, which merely restates the enum. Baseline 3 is correct.

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?

Uses a specific verb and resource ('Describe one table of a database') and enumerates exactly what is returned: columns, type, nullability, default value, primary key. This clearly separates it from data_tables (which lists tables) and data_query, though no sibling is named explicitly, so it stops short of a 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?

Gives an explicit trigger: 'Call it before writing a query against a table you have not seen.' That ties the tool to the data_query workflow and states the condition that selects it. It does not state when not to use it (e.g. for a table you already know or for views), so it is not a full 5.

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