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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds useful context (fixed UK coverage of 528 generations, role as a coverage check), but says nothing about matching behavior (partial vs fuzzy), result limits, or what an empty result implies.

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, zero filler. Scope and purpose come first, followed immediately by the usage routing, which is the right front-loading for an agent scanning tool lists.

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-only lookup with a fully documented schema and annotations, the description covers purpose, coverage, and routing. The only omission is what a match looks like on return, which is minor for a search tool with no output schema.

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 parameter with 100% schema coverage, and the schema already calls it a "free-text query, e.g. \"focus\"". The description's "by free text" restates the schema rather than adding matching rules or formatting guidance, so baseline 3 applies.

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 ("Search the covered vehicles ... by free text") plus scope (528 UK model generations). It explicitly names the sibling tool mot_reliability, so an agent can distinguish the two without opening either schema.

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 before calling mot_reliability" gives a clear workflow position and sequencing relative to the only sibling. It stops short of stating what to do in edge cases (no matches, ambiguous matches) or whether this is ever unnecessary, so it falls just short of full when/when-not guidance.

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