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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds the behavioral context that the tool is meant to be used before product selection, which is useful. However, it doesn't disclose details like whether the list is static or dynamic, or whether it requires any authentication, but the annotations carry most of the burden.

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?

Two sentences, no wasted words. The core purpose is front-loaded, and the usage instruction is concise. Every sentence earns its place.

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 simple list tool with read-only annotations, the description is mostly complete. The main gap is the undocumented 'query' parameter, which could affect how the agent calls the tool. The output schema is absent, but for a list tool the return format is likely obvious. The usage instruction adds conversational context that helps the agent.

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 0%, so the description must compensate for the parameters. The description mentions 'Russian delivery regions' which implies the country parameter is RU, but it doesn't explain the 'query' parameter at all. The schema shows query is optional with a maxLength of 80, but the description gives no hint about what query does (e.g., filtering regions by name). This is a gap.

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 clearly states the tool lists supported Russian delivery regions, which is a specific verb and resource. It distinguishes itself from sibling tools like products_search and product_details by focusing on delivery regions rather than products. However, it doesn't explicitly name a sibling alternative, so it doesn't fully differentiate from potential region-related tools.

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 provides explicit usage guidance: 'Ask the user to select a region before selecting products.' This tells the agent when to use the tool in a conversation flow. It doesn't mention when not to use it or name alternatives, but the context is clear enough for a list tool.

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