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

Annotations only declare it is a non-readonly, non-idempotent, non-destructive mutation. The description goes well beyond: it warns that slot conflicts are NOT validated, and that the respondent receives an email when schedule notifications are on — both material side effects an agent could not infer from the schema or annotations.

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?

Four sentences, front-loading the most important caveat (unchecked slot availability) before the operation list. Efficient, with only minor redundancy between the boundary requirement in the description and the schema.

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 mutation tool with no output schema, it covers operations, the reschedule invariant, a prerequisite read tool, and the notification side effect. Only the absence of any exclusions or a success/failure return note keeps it from being fully complete.

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 schema already documents all six parameters with formats and the enum values. The description restates the start/end coupling requirement, which the schema already notes (передаётся вместе с началом), so it adds little beyond the structured fields.

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 names a specific verb (изменяет запись) and enumerates the exact operations available: confirm, cancel, mark no-show, reschedule. It is clearly distinguishable from sibling tools like create_booking_block or get_booking_journal.

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 concrete prerequisite/alternative: slot availability is not checked on reschedule, so consult get_booking_journal first. That is strong actionable context, though it offers no explicit exclusions or comparison against other mutation siblings.

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