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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds real context beyond that: the data comes from already-collected data, no registry call is made, and the response is an ordered event log with old/new values plus source registry and effective_at/observed_at timestamps. It does not discuss limit behavior or empty/unknown-entity outcomes, which the schema partly covers.

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?

Front-loaded and dense with useful detail, and the payload structure is stated efficiently. The trailing Russian sentence duplicates the opening claim about the change log for the UNP, which is redundant text rather than new information.

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 annotations covering safety and an output schema present, the description does not need to explain return values, yet it still conveys the event model, data source, and zero-side-effect timing. An agent has everything needed to decide to call it and interpret the result.

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%, with unp format (exactly 9 digits, invalid_unp on violation) and limit bounds/default/ordering fully documented in the schema. The description adds no parameter-level syntax or constraint beyond that, so the baseline 3 applies.

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+resource+scope: an ordered change log per predicate for a Belarusian entity identified by UNP, drawn from collected data. It enumerates the event types (created/reaffirmed/superseded/conflict_detected) and the payload each carries, which is far more than a restatement of the name and clearly separates it from lookup/search siblings.

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 use case ('read anomalies over time — sudden address/head/activity change') and a selection-relevant fact ('Instant, no registry call'), implying it is the right choice when historical change tracking is needed rather than a live lookup. It does not explicitly name a sibling (e.g. lookup_company for current state) as the alternative, so it stops short of full when/when-not routing.

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