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

With no annotations at all, the description carries the full burden and does well: it discloses that every update is a total replacement, that html_content downgrades a multi-file site to a single file, and that the site URL is preserved. It does not cover failure modes (nonexistent page_id, PIN format rejection, size limits beyond the schema) or what the response contains, which keeps it short of a 5.

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?

Three sentences, front-loaded with the core action and immediately followed by the destructive full-replacement caveat, then the partial-update shortcut. There is mild redundancy between 'заменяет контент … и/или меняет PIN и видимость' and the final sentence, but nothing wasteful enough to penalize heavily.

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 six-parameter mutation tool with no annotations and no output schema, the description covers the critical risk (total replacement), the parameter interaction rules, and the invariants (URL unchanged). It stops short of documenting the return value or error conditions, which an agent may want before invoking a destructive call.

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 100%, so the baseline is 3, but the description adds real semantics beyond the schema: the mutual exclusivity of html_content and files, the single-file conversion side effect of html_content, and the fact that pin/visibility alone constitute a valid partial update. These are behavioral consequences of parameter choice that the schema does not encode.

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 precise verb and resource (update a previously published site by its identifier) and enumerates exactly what can change: content via html_content or files, plus PIN and visibility. The phrase 'ранее опубликованный сайт' together with the page_id reference implicitly separates it from htmlkin_publish, which creates sites, so an agent can tell the two apart without reading 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?

It gives a clear conditional recipe: pass only pin and/or visibility to change protection or visibility without touching content, and html_content or files (not both) to replace content. What it lacks is an explicit exclusion against siblings such as htmlkin_delete (use that to remove rather than replace) and any statement about permissions or required account state.

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