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 behavior beyond that: result-set size limits (25 per page, 100 per query) and the fact that country filtering is by country of award rather than headquarters. Not quite a 5, since it doesn't say what happens at the pagination ceiling.

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?

Three dense sentences, front-loaded with the entity definition, then filters, then paging. Every clause carries information; the middle sentence is slightly overloaded with the field enumeration, but nothing is redundant.

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?

A read-only list tool with annotations covering safety and no output schema, so the description must convey what comes back: it does, listing the aggregate fields and the card/page links. Paging limits are stated. Only the enumeration of kind values and the lang behavior are left entirely to the schema.

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?

At 33% schema coverage the description must carry weight, and it does: it explains that country matches firms with awards there, that query matches words of the name, that page_size tops out at 25, and it restates the paging model. The lang parameter's purpose (language of page links) is only covered by its schema description, keeping this below a 5.

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 and resource and defines the population precisely: consulting firms winning European public contracts that have a firm card. It also enumerates the returned fields (awards in 24 months, value won, main country, kind of work, links), which lets an agent distinguish it from the single-entity get_firm. No sibling is named explicitly, so it stops short of a 5.

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 names the available narrowing dimensions (country, kind, name words) and the parenthetical "firms with awards there" clarifies country filter semantics, which is real usage help. However, it never says when to reach for this over get_firm or search_tenders, nor any exclusion such as 'use get_firm to fetch details of one firm'.

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