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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), yet the description adds genuinely new behavioral context: results are newest-first, each change names the moved fields, source and date, and the important caveat that proposed-vs-in-force status is only stated when a source says so. That caveat prevents an agent from over-claiming certainty, which is real value beyond the annotations.

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 compact sentences with zero filler: scope and ordering first, then the returned fields, then the qualification about proposed vs in force. Each sentence carries distinct information.

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?

With no output schema, the description does the work of explaining what a result row contains (moved fields, source, date), which is what an agent needs to interpret the response. It stops short of noting any result cap, truncation, or what an empty result means, a minor gap for a recently-changed feed.

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%, so the schema already documents all three parameters including the 90-day default and the country/visa id formats. The description reinforces the country-vs-visa scoping but adds no syntax, default, or interaction detail beyond the schema — 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?

The description names a specific resource ('recent recorded changes to a visa's rules or to its official source page') with explicit scope and ordering, which is clearly distinct from siblings like transita_visa_details or transita_programme_status. It does not explicitly route against those siblings, so it falls just 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?

Usage is implied rather than stated: an agent can infer 'use this to see what recently changed,' and the 'for one visa or every visa in a country' phrase hints at two access modes. But there is no explicit when-to-use, when-not-to-use, or named alternative (e.g. transita_visa_details for full current rules).

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