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

Annotations state only readOnlyHint and openWorldHint; the description adds substantial non-annotation behavior: changes are derived from this service's own observation record, include polling gaps and last-seen-old-state timestamps, the free window is clamped to 30 days, and the output relays MOFA without advice. That is exactly the kind of provenance and caveat detail the annotations cannot carry.

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?

Dense but front-loaded, opening with the core question and then qualifying scope, window, and provenance. Every sentence carries information, though the parenthetical clause about region texts is somewhat awkward and the reference to an undefined 'tracking_since' adds minor noise.

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 shape need not be explained, and the description supplies the windowing rule, provenance, and observation-model caveats. The only gap is the undefined 'tracking_since' and 'history_window' references, which leave a small ambiguity about where those are defined.

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%, so the baseline is 3, but the description adds meaning the schema lacks: that an earlier 'since' is clamped (schema simply calls it an ISO date) and that include_notice_updates relates to re-issued notices with unchanged levels. The 'tracking_since' wording does not match the actual parameter name 'since', slightly muddying the mapping.

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 states a specific verb+resource: which countries had MOFA danger or infectious-disease levels (or region texts) change since a given time. That is clearly distinct from mofa_country_levels, which returns current levels. It does not name the sibling explicitly, so it stops short of a 5.

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?

It gives real operational context: results are limited to changes since tracking_since as observed at our polling times, and since values older than 30 days are clamped, with a pointer to history_window. No explicit 'use X instead of Y' routing is given, which keeps it at 4.

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