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

Annotations already declare readOnly/idempotent/destructive behavior, and the description adds material context beyond them: result size (~180 entries), ordering (most changes first, then by code), null-vs-0 heat semantics, the Free-key 7-day data limit, and quota/cost behavior including that a rejected argument costs nothing.

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 dense but front-loaded: purpose first, then usage/exclusions, then parameters, then behavior and cost. Every segment carries information, though the parameters sentence partially duplicates the already-complete schema descriptions.

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 two-optional-parameter list tool with an output schema, the description covers everything an agent needs to call it correctly: scope, alternatives, ordering, null semantics, plan-based data limits, and quota cost. Return values are covered by the output schema and additionally summarized.

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 coverage is 100% and both enum parameters are already fully documented in the schema, so the baseline is 3. The description's parameter notes largely restate the schema (domain filtering, locale affecting names) and only lightly adds the fallback framing, so it does not clearly exceed the schema's information.

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 every country and territory AiSeek places changes in') plus the exact payload (name, count in last 7 days, Change Heat on the last day). It explicitly names the sibling tools it is not (get_country_heat, get_earth_view), so an agent can select it without opening any schema.

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?

Gives two positive use cases ('get all country codes at once', 'see which countries have news') and two explicit exclusions with routing: get_country_heat for heat details and seven-day series, get_earth_view for a single place. When/when-not/alternatives are all present.

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