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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=false), so the bar is lower. The description still adds real context: shipping costs are not returned here, are computed at checkout from the postcode, and should not be guessed. It stops short of describing pagination or exact return shape, but that is minor for a static list.

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 sentences, all front-loaded with the highest-value information first (what it lists, when to call it, what it does not return). No filler.

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 parameterless read-only list tool with no output schema, the description covers what is returned (ISO country codes), the boundary condition (no shipping costs, USA not supported), and the intended downstream usage. Nothing needed to call it 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?

The tool takes zero parameters, which is the baseline-4 case. The only parameter-ish detail (passing `country` to other tools) belongs to the downstream tools, not this one, so there is nothing further to add.

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?

States a specific verb (List) and resource (countries delivered to), scoped to Brick Premium raised beds, and notes the return format is ISO codes. This is clearly distinguishable from sibling tools like studio_pricing_quote or studio_catalog_bricks.

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?

Explicitly says when to use it (before quoting) and how to chain it (pass the user's country as `country` to studio_pricing_quote or studio_create_design). It also names an exclusion: delivery to the USA is not offered.

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