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

With no annotations, the description carries the full burden. It does disclose a genuinely useful behavior — refusal with do_not_answer when a fact is drifted or unverified, and that it never guesses — but leaves undefined what "drifted" or "unverified" mean, what the successful response contains, and whether a refusal is an error or a normal payload. The terminology is unexplained jargon.

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, front-loaded with the action and followed by the refusal contract; no filler. Minor deduction because the compressed pack/drift vocabulary costs clarity without saving much 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 single-parameter lookup with no output schema and no annotations, the description covers the failure mode but not the return shape, the origin of fact_id, or the meaning of the pack concept. Enough to attempt a call, not enough to handle the result confidently.

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?

There is a single required parameter, fact_id, at 0% schema description coverage, and the description says nothing about its format or where an agent obtains a valid id (presumably from childcareuk_list_facts). With low coverage, the description is expected to compensate and does not.

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 verb and resource ("Get one verified fact from the childcareuk pack"), and the singular "one fact" implicitly separates it from the sibling list/changes tools. It doesn't explicitly name those siblings, so the differentiation is inferable rather than stated.

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: retrieving a single fact by id contrasts with childcareuk_list_facts for discovery, but the description never says so, nor when to prefer childcareuk_changes. There are no explicit exclusions or preconditions for calling it.

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