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

Annotations cover the safety profile (readOnly, idempotent) and closed-world scope, so the description only needs to add context. It does: the exact returned fields (buyer, incumbent supplier(s), value, start and expected end date) and a cost note ('free during beta'), which matter since there is no output schema. It omits result ordering and pagination behavior.

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, zero waste: the first carries the concept and the commercial/positioning context, the second enumerates return fields compactly. Front-loaded with what the tool is before the payoff framing.

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 no output schema, the description supplies the return contents; with only optional filters, there is little else an agent must know to call it. The gap on ordering/pagination is minor for a capped (max 50) read-only list.

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% across all 7 optional filters, so the schema already documents buyer, region, countries, min_value, cpv_prefixes, months_ahead and limit with examples. The description adds nothing parameter-specific beyond 'term ends soon' loosely mapping to the default 12-month window, 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?

States a specific resource (public contracts whose term ends soon) with a clear framing — 'a sales pipeline before tenders are published' — that positions it as distinct from search_tenders (published tenders) and award_history (past awards). An agent can identify what it gets without opening the schema.

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?

Implies the use case clearly: prospecting for re-tenders that haven't been published yet, which implicitly routes published-tender queries to search_tenders. It stops short of naming an alternative or stating an explicit when-not condition, so it falls just short of a 5.

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