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

With no annotations, the description carries the full burden, but it does disclose the response payload (fact ids plus verification states), which is meaningful behavioral context for a zero-parameter tool. It says nothing about read-only safety, result volume, ordering, or what a 'verification state' can be, leaving real gaps.

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?

A single front-loaded sentence with no filler; the parenthetical domain tag helps disambiguate across the many sibling prefixes. It is efficient, though the terseness contributes to the missing usage context rather than resolving it.

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 and no annotations, the description is the only source for return shape, and it names the fields but not their possible values or count/cardinality behavior. For a simple zero-param list tool this is adequate but leaves the agent guessing about what 'verification states' contains.

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?

The tool takes no parameters, so the schema-and-description split is moot and the baseline of 4 applies. There is no filtering or scoping argument the agent could mistakenly expect to pass.

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?

Specific verb plus resource: 'List fact ids + verification states', scoped to the mileageuk domain. The agent can tell it apart from mileageuk_get_fact and mileageuk_changes by name, but the description itself does not articulate that distinction, so it falls 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?

There is no when-to-use guidance and no stated alternative. The agent must infer from the sibling naming convention that this is a discovery step preceding mileageuk_get_fact, and nothing tells it when to prefer mileageuk_changes instead.

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