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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description goes beyond annotations by adding 'Freshness-stamped', disclosing the data may be the last known set, that no-data results in no charge, and that consuming this tool costs 2 credits. This is useful behavioral context without contradicting any annotation.

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?

The description is about three sentences, front-loading the core output, then listing fields, then the freshness/pricing note. The phrase '2 credits' repeats the tile, which is slight redundancy, but overall there is no wasted detail. It is efficient and well ordered.

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?

With a single parameter and no output schema, the description carries most of the responsibility for return semantics. It lists every category of returned data and mentions the no-charge/no-data outcome. It does not define domain terms like 'DNA profile' or 'match tier', but they are not essential for selecting or invoking the tool.

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 only parameter, domain, is documented with 100% schema coverage ('eCommerce domain, e.g. gymshark.com'). The description merely repeats 'for a domain' without adding new syntax, format constraints, or examples beyond what the schema already says. With full schema coverage, the baseline of 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 the tool returns the 'last-known DNA competitor set' for a domain, specifying the source (RivalSweeper) and the exact fields returned (name, website, country, home-market flag, match tier, and the brand's own DNA profile). This clearly differentiates it from sibling tools like get_competitor_price or get_competitor_top_urls, which address different data types.

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?

The description does not state when to use this tool versus alternatives, nor does it include any 'use X instead' guidance. It mentions 'last-known' and 'freshness-stamped', but that is about data from freshness policy, not about selecting it. Without any textual pointer to siblings, an agent may not know when this 'DNA competitor set' is the right call versus get_brand_snapshot or get_competitor_top_urls.

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