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

Annotations already declare idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds two genuinely new behavioral facts: is_active acts as pause/resume, and a 404 means the sync was not found. It does not say whether omitted fields are left unchanged (partial update) or reset, which is the most important behavioral question for a 7-parameter update tool.

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?

Two short clauses, front-loaded with the core action and field list, with the error case appended at the end. No wasted prose; the terseness is the only mild issue since more meaning could have been packed into the same space.

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 seven parameters, no output schema, and no nested objects, the description covers the action and the 404 outcome adequately for a minimal call. It falls short on partial-update semantics and on value formats for the two enums, schedule_time, and schedule_day, leaving the agent to guess field constraints.

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 must carry parameter meaning, but it mostly just re-lists property names already visible in the schema. Only is_active gets real added semantics (pause/resume); frequency and direction enums, schedule_time format, and what schedule_day means (day of week vs. day of month) remain unspecified, and sync_id is never explained.

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 verb and resource ('Изменить синхронизацию') and enumerates the mutable fields, so it is clearly an update operation on an existing scheduled sync. It does not explicitly contrast with siblings like create_scheduled_sync or run_scheduled_sync, but the name plus the 404-on-missing note make the target unambiguous.

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?

Usage is implied rather than stated: it modifies an existing sync, and the 'is_active — пауза/возобновление' note gives a useful operational hint for pausing/resuming without a separate tool. There is no explicit when-to-use/when-not-to-use guidance (e.g., vs. run_scheduled_sync or create_scheduled_sync), and no mention of prerequisites such as ownership.

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