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

Annotations already declare readOnlyHint=true, so the safety profile is covered by structured data. The description adds the concrete endpoint (GET /api/integration/countries), confirming a read, but says nothing about pagination defaults, result volume, or whether the list is tenant-scoped versus global.

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 short sentences with zero filler, and the purpose is front-loaded ahead of the endpoint detail. Slightly more terse than ideal for a tool with a filter parameter, but nothing is wasted.

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 read-only list tool with full schema coverage and a safety annotation, the definition is close to sufficient. The remaining gap is that no output schema exists and the description never indicates what a country record contains (code, name, active flag), leaving the return shape to discovery.

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 100%: page, per_page, and search_string are all documented in the schema. The description adds no meaning beyond that, so the baseline 3 applies.

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 ("List countries known to the platform"), which is unambiguous against siblings like list_all_currencies or list_organisation_currencies. It does not explicitly name a sibling to distinguish from, but the resource noun is distinct enough that no routing ambiguity exists.

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?

There is no guidance on when to use this tool versus the currency/pricing siblings, nor any prerequisites or exclusions. The only usage signal is the implicit one that it is a list endpoint, which the agent must infer entirely from the name.

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