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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description's job is to add semantics beyond them — and it does, explaining that EUR totals are deduplicated committed procurement value with tenders/budgets excluded. That prevents a serious misreading of the numbers. It still doesn't say how an unknown or malformed ΑΦΜ is handled.

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 sentences: purpose first, then the critical measurement caveat. The second sentence is dense but every clause (deduplication, lifecycle coverage, exclusions) changes how the numbers should be read, so it earns its length.

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?

An output schema exists, so return values need no explanation, and for a one-parameter lookup the description is nearly sufficient, with the deduplication semantics being the key addition. Minor gaps remain around error/empty-result behavior and the meaning of 'role'.

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?

Single parameter with 100% schema coverage, so the baseline is 3. The description's '9-digit ΑΦΜ' merely restates the schema text without adding format examples, normalization rules, or what happens when the entity is absent from the registry.

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?

States a specific verb+resource (profile of a legal entity) and enumerates the content returned: name, role, buyer/supplier spend and receipt statistics. The 'by 9-digit ΑΦΜ' key implicitly separates it from find_entity (name-based lookup) and entity_counterparties, though it never names those siblings explicitly.

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 only implied: the agent must infer that this is the tool to call when it already has a 9-digit ΑΦΜ, and that find_entity is the alternative when it only has a name. No 'when not to use' or prerequisite statement is given.

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