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

Annotations already carry the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description correctly spends its words on what each mode actually returns — member, invitation, meeting, series and dashboard-link content. That is real added context beyond the annotations; only the absence of notes on auth expiry or empty results keeps it from 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?

A single front-loaded sentence: resource first, then the conditional mode switch. Every clause earns its place, though the semicolon-dense, verb-less phrasing is slightly telegraphic.

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 no output schema, the description correctly enumerates the fields returned in card mode and covers both call shapes. Nothing essential is missing for correct invocation; edge cases like unknown group_id or pagination are simply out of scope.

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 only 50% (group_id is undocumented in the schema), and the description compensates by explaining that group_id switches the tool into group-card mode. The access_token parenthetical merely echoes the schema note, but the critical optional parameter is given meaning.

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?

Names a specific resource (пользовательские группы) and specifies a dual behavior: without group_id it lists groups, with group_id it returns a full group card enumerating participants, invitations, meetings, series and a dashboard link. It is unmistakable next to create/invite siblings, though it never names them explicitly.

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 'с group_id' clause is an explicit routing condition telling the agent when to get the detail card versus the plain list. It gives no when-not-to-use guidance and points to no alternative sibling, so it stops 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.