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

With no annotations, the description must carry the load; it does disclose the return payload (fact ids plus verification states), which implies a read-only enumeration. It says nothing about ordering, result volume, or whether listing is exhaustive for the domain.

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 short sentence with the payload front-loaded and no filler. The trailing '(pensionuk)' is somewhat redundant with the tool name and sibling prefix, a minor wasted clause.

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 zero-parameter, no-output-schema list tool the definition is minimally sufficient, but it leaves unclear what a 'verification state' contains and how the listing relates to pensionuk_changes or pensionuk_get_fact. Adequate without being complete.

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 zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description correctly implies a bulk/no-filter enumeration rather than a targeted lookup.

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 ('List') and the exact return contents ('fact ids + verification states'), scoped to the pensionuk domain. An agent can tell it apart from pensionuk_get_fact, though it never explicitly contrasts itself with pensionuk_changes.

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?

No when-to-use guidance, no mention of the discovery-then-fetch pattern with pensionuk_get_fact, and no exclusions. The '(pensionuk)' scoping is the only contextual hint, so the agent must infer routing from sibling names alone.

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