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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description's added value is real: it discloses the upstream source (GOV.UK Content API), that data is live, that only the latest change per country is returned, and that a call costs 1 credit. It stops short of describing pagination or response size behavior for the limit parameter, so not a full 5.

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?

It is front-loaded with the user question it answers, then the payload, source, scope limitation, alternative, and cost — a sensible order. There is minor redundancy between the opening question and the following sentence describing the update time and one-line summary, but no sentence is expendable.

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 still tells the agent what comes back (per-country update timestamp plus the FCDO's summary line). For a zero-required-parameter read tool with full schema coverage, nothing needed to call 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?

Schema description coverage is 100% for the single optional 'limit' parameter, so the schema already carries the range and default. The description adds no meaning beyond that, which is the expected baseline when structured fields do the work.

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 (FCDO/UK travel advice pages) and a specific ordering and payload (newest first, with update time and the FCDO's one-line change summary). It explicitly distinguishes itself from the sibling travel_advice_country, so an agent can select it without opening the 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?

It states the boundary condition ('Shows only the latest change per country') and names the exact alternative tool for the excluded case ('use travel_advice_country for a country's earlier changes'). It also names the intended audience, which clarifies the use context further.

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