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

Annotations already declare readOnlyHint=true, and the description reinforces this by stating 'Does not purchase or charge.' It adds useful behavioral details beyond annotations: the price is valid for 15 minutes and likes/views are divided evenly across selected posts.

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 description is two short sentences with no filler. The core purpose is front-loaded, and the extra behavioral notes are compact and relevant.

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?

The tool is simple and the description covers the most important behavioral context, but given no output schema and no parameter descriptions, an agent still lacks guidance on how quantity, username, platform, and postUrls interact. It is minimally viable but incomplete.

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 input schema has 0% description coverage, so the description must carry parameter meaning. It only mentions 'likes/views' and 'selected posts' in passing; it does not explain platform, username, type, quantity, or postUrls semantics. This is insufficient for a 5-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 uses a specific verb ('calculate') and a clear resource ('server-verified price'), and immediately distinguishes itself from purchase-related siblings by stating it 'does not purchase or charge.' This makes the tool's purpose unambiguous.

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 description conveys when to use this tool: to obtain a price before any commitment, with a 15-minute validity window. It also states what the tool does not do ('Does not purchase or charge'), but it does not explicitly name the sibling tools that should be used for the actual purchase/order flow.

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