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

With no annotations, the description carries the full burden, and it does disclose one genuinely useful behavior beyond the schema: a do_not_answer refusal path for drifted or unverified facts rather than a guess. It says nothing about the success payload (what a "fact" record contains) or the shape of the refusal response, leaving the agent to discover return structure empirically.

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 core action and immediately followed by the failure contract. "Never guesses" mildly restates "refuses when unverified" but reinforces the key guarantee at negligible cost.

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 lookup with no output schema and no annotations, the definition covers the action and the important refusal semantics. The remaining gap is the missing fact_id provenance and return shape, which matter more here than for a richer tool but are secondary to the disclosed do_not_answer contract.

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 required fact_id parameter, so the description must compensate and it does not — no format, naming convention, or provenance (e.g., obtained from broadbanduk_list_facts) is given. The only parameter is effectively undocumented in both structured and natural-language form.

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 states a specific verb and resource ("Get one verified fact") and scopes it to the broadbanduk pack, which together with the tool name distinguishes it from the many sibling get_fact tools for other domains. It does not name the sibling (broadbanduk_list_facts) that supplies fact identifiers, so differentiation is clear by domain but not by workflow.

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 implied: retrieve a single fact by id, and expect a refusal when the fact is drifted or unverified. There is no explicit guidance on when to prefer this over broadbanduk_list_facts or broadbanduk_changes, nor a statement of where valid fact_ids come from. An agent can infer the workflow but must guess at the entry point.

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