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

Annotations already cover openWorldHint=true, idempotentHint=false, and destructiveHint=false, so the safety profile is handled. The description adds real value beyond that: it discloses that each execution is incremental, that every_5_min is plan-restricted, and it maps concrete failure modes (403 for plan-unavailable frequency, 400 for bad connection_id or source==target). That is meaningful behavioral context an agent could not get from the 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?

The content is dense but front-loaded: the operation is stated first, then parameters, then errors, in a single semicolon-delimited block. Every clause contributes information and nothing repeats the schema. It is slightly cramped as one paragraph and could be structured into lines, but no wording is wasted.

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 an 8-parameter creation tool with a nested filters object and no output schema, the description covers nearly all decision-relevant detail, including plan restrictions and error semantics. The main omission is what happens on success (e.g., whether a sync ID is returned for later use with run_scheduled_sync or update_scheduled_sync), which matters for chaining calls.

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 0%, so the description carries the full burden and largely succeeds: it enumerates the frequency enum values (including the Pro-only option the schema enum does not flag), gives the 'HH:MM' format for schedule_time, explains the dual meaning of schedule_day (0-6 weekday for weekly vs day-of-month for monthly), defines direction values, and outlines the filters sub-keys. The gaps are 'name' (never explained) and the meaning of source/target connection IDs beyond the error hint.

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 opening sentence states a specific verb and resource ('Создать регулярную синхронизацию') and clarifies the operational semantics: each run incrementally transfers new/changed files. That distinguishes it from a one-off transfer in substance, but it never names a sibling tool (create_transfer, update_scheduled_sync) as the alternative, so the differentiation is implied rather than stated.

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 implies the usage context through parameter documentation and plan-gating ('every_5_min — только Pro'), and the error notes hint at preconditions. However, it never explicitly says when to choose this tool over create_transfer (one-time) or update_scheduled_sync (modify existing), nor does it state prerequisites such as needing valid connection IDs beforehand. Usage guidance remains inferred.

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