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

With no annotations, the description carries the full disclosure burden; it does add genuinely useful context that the window is bounded by when the server began tracking the site, and that results span multiple change categories. It falls short on return shape (what fields a change entry has, URLs, old/new values), ordering, result limits, and whether the call is expensive.

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 core purpose is front-loaded in the first clause, and the enumeration of change types plus the `kind` value list is dense and earns its space. Slightly list-heavy, but no filler sentences.

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 two-parameter read tool with no annotations and no output schema, the description needs to say what a returned change record looks like and how results are ordered/limited; it does not. The tracking-window caveat and kind enumeration cover the most important gaps.

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 coverage is 0% and neither parameter is documented in the schema, so the description must compensate. It does this well for `kind` by enumerating all eight accepted values, but `days` is only obliquely implied by 'за последние дни' — its default of 7 and its interaction with the tracking-start bound are never stated.

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-like function (report what changed) and enumerates the exact change classes returned: new/departed products, price and stock changes, card updates, new articles, page text updates. It is clearly distinguishable from siblings like usilitel_products_search or usilitel_content_search, though it does not explicitly name a sibling it is not.

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 by the framing 'what changed since the server started tracking,' which tells the agent this is a delta/digest tool rather than a current-state query. However, there is no explicit when-to-use vs when-not-to-use guidance and no mention of alternatives such as usilitel_refresh or usilitel_content_search.

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