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

No annotations are supplied, so the description carries the full behavioral burden, and it does surface an important failure mode: the tool refuses with do_not_answer when content has drifted or is unverified, and never guesses. What it omits is the shape of a successful response and whether a refused call is distinguishable programmatically from an empty one.

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?

Two short sentences with the scope up front and the refusal behavior second; nothing is padded. 'the studentloanuk pack' is slightly jargon-y but does not waste space.

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 one-parameter read tool with no annotations and no output schema, the refusal behavior is the most important thing to disclose and it is covered. Still missing is how an agent obtains a valid fact_id and what a returned fact looks like, which leaves a real gap before the tool can be invoked reliably.

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 0% for the single parameter, so the description must compensate and does not: it never explains that fact_id identifies a specific fact or that valid IDs come from studentloanuk_list_facts. 'One verified fact' only weakly implies that the argument selects a fact.

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 uses a specific verb and resource ('Get one verified fact from the studentloanuk pack'), which is clearly distinguishable from the sibling tools that list facts or report changes. It stops short of an explicit contrast with studentloanuk_list_facts, but the domain prefix and singular scope make the target obvious.

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 only implied: fetching a single known fact rather than browsing, which points an agent away from the list_facts sibling. The description never states when to prefer it over studentloanuk_list_facts or studentloanuk_changes, nor any prerequisite such as needing a fact_id first.

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