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

Annotations already declare read-only, idempotent, open-world and non-destructive, so safety is covered. The description adds meaningful context beyond annotations: each change carries the record before and after, a link to the official topic page, and the source authority claim ('The portal is authoritative. Free.'). It does not describe result ordering or rate limits, keeping it below a 5.

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?

Purpose and coverage are front-loaded in the first sentence, followed by two short, useful sentences on polling and authority. The parenthetical programme list is dense but earns its place by defining scope; slightly long single sentence, but no filler.

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 must cover return values, and it does: before/after records, official page link, and next_cursor. For a six-parameter, filter-only read tool this is nearly complete; only ordering, deduplication and empty-result behavior are unstated.

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 coverage is 100% with enum and range descriptions for field, change, limit, since and identifier, so the schema does the heavy lifting. The description only reinforces the cursor parameter's paging/polling role and adds no new meaning for the other filters; 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 verb+resource ('Changes to open and forthcoming EU funding opportunities') and enumerates the covered programmes and change types (new calls, moved/added deadlines, status changes, closures/withdrawals). This clearly separates it from siblings like get_tender_deadline_changes (tenders) and eu_contract_awards.

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 concrete usage guidance for paging/polling ('Pass next_cursor back as cursor to page or to poll'), which implies recurring polling is expected. However it never states when to prefer this over sibling deadline/change feeds such as get_tender_deadline_changes or eu_compliance_deadlines, so routing remains inferential.

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