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

Annotations already set readOnlyHint=false, idempotentHint=false, and destructiveHint=false. The description adds valuable behavior beyond annotations: 'Не переданные поля не трогаются' discloses partial-update semantics, and the note about client_source explains that respondent address comes from elsewhere. It does not cover permission or SMTP prerequisites, but those appear in the schema.

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 three front-loaded sentences with no wasted text. It moves from the core purpose to the two-email scope, then to update and address caveats. It is appropriately sized for an 18-parameter tool, though it could be slightly more structured with explicit labels for the caveats.

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?

Given 18 parameters, one required field, annotations covering safety and idempotency, and no output schema, the description supplies the essential behavioral context: what is saved, the two independent email templates, partial-update behavior, and where the respondent address comes from. It does not explain the raw HTML/SMTP interaction in detail, but that is covered by the schema descriptions.

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 the detailed parameter meanings are already documented in the schema. The description adds a small amount of semantic context for client_source and the partial-update behavior, but it does not significantly extend parameter semantics beyond what the schema provides. The baseline of 3 is appropriate when the schema does the heavy lifting.

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 action and resource: 'Задаёт тему и текст писем опроса' (sets subject and text of quiz emails). It immediately distinguishes the two independent email streams, author and respondent, and clarifies that respondent address is not configured here. This is enough for an agent to distinguish it from siblings like get_quiz_email_settings or set_quiz_email_questions.

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 gives clear context for usage: two independent letters, non-passed fields are left untouched, and respondent address is not set via this tool but sourced from an answer or hidden variable via client_source. It does not explicitly name an alternative sibling tool, but the when-not guidance for respondent address and the partial-update semantics are strong usage context.

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