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

Annotations already declare readOnly/idempotent/closed-world, and the description goes well beyond them by disclosing the matching algorithm (substring-based, case-insensitive over brand, resolved model name, and raw Build.MODEL) and the ranking rule (exact match, then popularity). That is the kind of behavior an agent needs to predict result quality and ordering.

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 paragraphs with the purpose front-loaded and the matching/ranking detail second. Every sentence carries information, though the 'meant for phones named in free text' clause slightly overlaps the preceding sentence.

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?

An output schema exists, so return values need no explanation, and annotations cover the safety profile. The description supplies the remaining decision-relevant context: why exact-match siblings fail and how results are matched and ranked.

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 100%, so both parameters are already documented, including the examples for 'query' and the separate per-list capping of 'limit'. The description adds no syntax or format detail beyond the schema, so the 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?

The description states a specific verb and outcome ('resolve free-form user text into the canonical brand / model identifiers') and immediately separates this tool from the sibling 'brands'/'models' tools, which match exactly. An agent can tell what this does and why it exists without opening the 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?

It clearly says when to use it ('meant for phones named in free text') and explains the failure mode that motivates it ('the other tools match brands and models exactly, so a guessed spelling returns an empty list'). It does not name a specific sibling alternative or state explicit when-not conditions, which keeps it short of a 5.

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