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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds useful behavior beyond that: the dataset's fixed scope (530 generations) and the fact that it is a live proxy to whatbreaks.uk, implying an external call with potential latency.

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 tight sentences with no filler; the scope and examples are front-loaded, and the downstream-tool relationship comes last where it reads naturally.

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 read-only search this covers purpose, scope, usage and external dependency adequately, and no output schema means return values needn't be described. It would be stronger if it hinted at what the result contains (generation names/IDs needed to feed uk_mot_reliability).

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?

With 100% schema coverage the baseline is 3, and the description adds real meaning by giving example queries ("focus", "golf") and clarifying that the free text matches against model generations rather than arbitrary fields. It still doesn't note matching rules (partial match, case sensitivity, aliases).

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 (search) and resource (530 UK model generations in the MOT dataset) with concrete query examples. It also distinguishes itself from the sibling uk_mot_reliability by framing this as the coverage/disambiguation step that precedes it.

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?

"Use to check coverage or disambiguate a generation before uk_mot_reliability" explicitly gives the condition for choosing this tool and names the downstream tool. It does not spell out when not to use it or contrast it with the other search siblings (e.g. uk_recalls_search), so it stops short of full routing guidance.

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