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

Annotations already establish readOnly, idempotent, non-destructive and closed-world, so the bar is lower; the description still adds useful behavior: unknown ids are reported and left out, and the output is a shareable page URL. One flaw: it says '2 to 30' ids while the schema allows minItems 1, an internal inconsistency that could mislead, though it does not contradict the annotations.

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?

The core purpose is front-loaded in the opening clause and the rest is a compact sentence covering ordering, title, id source and edge-case handling. It is slightly run-on with the parenthetical URL example and duplicated range information, but no sentence is wasted.

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 only two parameters, no output schema and full schema coverage, the description supplies everything an agent needs: what is returned (a list page URL), where the ids come from, the ordering guarantee, and what happens with invalid ids. The only residue is the min-items mismatch, which is a schema/description consistency issue rather than missing context.

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%, so the baseline is 3, but the description adds value beyond the schema by specifying that ids must come from search_deals, get_deal or get_meal_ideas and that their order is preserved in the output. It reinforces title as optional; the count guidance conflicts slightly with the schema's minItems.

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?

The description states a concrete verb+resource: it builds one link that opens several promotions together on a dealio.be list page, in the given order, with an optional title. It also clarifies its role relative to siblings by naming search_deals, get_deal and get_meal_ideas as the id sources, so an agent can tell it is an aggregator/builder rather than a lookup.

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 clear context for use: 'for the promotions you propose to the user after one or more searches, so they need not open them one by one', which tells the agent when this is the right call. It also routes id collection to specific sibling tools. There is no explicit 'when not to use' (e.g. a single promotion needing no list link), so it stops short of the top mark.

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