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

With no annotations supplied, the description carries the full behavioral burden, and it does disclose the key trait: the tool refuses with a do_not_answer result when a fact is drifted or unverified rather than guessing. That is meaningful non-obvious behavior an agent must plan around. It stops short of describing the success response shape or what a drift condition looks like in practice.

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 purpose and followed by the failure mode. Every clause earns its place; nothing is padded or repeated.

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 in a large family of parallel pack tools, the description covers purpose and the refusal behavior, which is the most important edge case. It leaves the agent without guidance on sourcing a fact_id or on what a successful result contains, and no output schema exists to fill that gap.

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 single parameter has 0% schema description coverage and the description adds nothing about it — no format, no indication of where a valid fact_id comes from (presumably drivinguk_list_facts), no example. At this coverage level the description needed to compensate for the schema 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?

States a specific verb and resource ("Get one verified fact") and scopes it to the drivinguk pack, which distinguishes it from the parallel get_fact tools in the other domain packs. It does not explicitly distinguish itself from its closest sibling, drivinguk_list_facts, but the singular "one" implies single-record retrieval.

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 rather than stated: you call this when you already have a specific fact to retrieve. No alternative is named (drivinguk_list_facts would be the obvious one for discovering IDs), and there is no statement of prerequisites or when-not-to-use.

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