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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the default-edition behavior and the content scope, but describes the return contents that the output schema already documents, and says nothing about auth, rate limits or fallback when an edition is missing.

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 with the identity of the index, then usage triggers, then the default-period rule, so the important scoping information arrives early. The embedded Bulgarian phrases add some visual noise but each sentence still earns its place.

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 an output schema present, return values need no explanation, and the description covers what the index is, when to reach for it, and the default period. Nothing an agent needs to invoke it correctly is missing.

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 both parameters (period, language) are fully documented in the schema, including the YYYY-MM pattern and enum. The description's "latest edition unless a month is asked for" restates the schema's period default rather than adding new semantics, so 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?

It names a specific resource (the monthly Realistimo index of average asking prices per m² in Bulgaria's largest cities) and enumerates its contents (MoM/YoY change, top rising and falling квартали). This clearly distinguishes it from estimate/deal-cost siblings, but it never differentiates itself from the close sibling realistimo_market_stats, leaving some overlap to inference.

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 supplies concrete triggering phrasings ("как се движат цените на имотите", "пазарен индекс", "цени на имоти за септември") and a default rule ("The latest edition unless a month is asked for"). It stops short of stating when NOT to use it or naming market_stats as the alternative, so it is context-rich but without exclusions.

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