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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds genuinely useful behavior beyond them: 'Static data, no upstream request' tells the agent results are fixed and cacheable, and the returned columns are named. It does not need pagination/rate-limit notes for a fixed six-row 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 short sentences, front-loaded with the return content, then the static-data caveat, then the call-order instruction. No filler or redundancy.

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?

Output schema exists, so return-value documentation is optional, yet the description still names the row fields. Call order, accepted values, and static nature are all covered — nothing an agent needs to invoke 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?

Zero-parameter tool, so the baseline is 4. The description still adds value by enumerating the exact country codes (ci, eg, ke, ma, ng, sn) that the sibling tools' country parameter accepts, bridging this tool to their schemas.

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 and resource ('Returns the Jumia country storefronts'), enumerates the accepted country codes, and describes the row shape (code, name, domain, currency). It is clearly distinguishable from jumia_search / jumia_category / jumia_categories, which it names as downstream consumers.

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 prescribes the call order: 'Call it first to choose a storefront for jumia_search, jumia_category or jumia_categories.' That is a concrete when-to-use rule plus the sibling tools it feeds, leaving nothing to inference.

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