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

Annotations already establish read-only, idempotent, safe behavior. The description adds content-level detail about what is covered (no-key access, free/paid plans, links), but does not describe behavior such as return format or pagination, which the annotations do not need to cover.

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 sentence that packs the key information without padding. The phrasing is slightly awkward due to the parenthetical list, but every element adds value and the most important context (what is included) comes first.

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 no parameters and no output schema, the description does enough by enumerating the returned content categories. It could be more explicit about the output shape, but for an informational, zero-argument tool this is sufficiently complete.

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?

There are no parameters and schema coverage is 100%, so the schema carries no burden. The description appropriately focuses on output content rather than parameters, matching the baseline for a zero-parameter 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 identifies the resource as access levels and plans, listing concrete details: history depth, datasets, row limits, price, and signup links. It clearly differs from siblings like list_tables and run_sql, though it uses 'What...' rather than an explicit verb like 'returns' or 'lists'.

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?

The content strongly implies this is the tool to use when the agent needs plan, pricing, or access-limit information. However, it does not explicitly state when to choose this over alternatives or mention any conditions, leaving usage to inference.

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