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

With no annotations at all, the description carries the full behavioral burden. It does disclose the default sort order and that each deal carries a merchant_verified flag, but it says nothing about result-set size, pagination, rate limits, or what happens when many deals match — gaps that matter for a list tool with no output schema.

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 short sentences, front-loaded with the resource and scope, with ordering and filter behavior following. The parenthetical '(see merchant_verified per deal)' is slightly awkward without an output schema to anchor it, but nothing is padded or 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?

For a four-parameter read tool with no annotations and no output schema, the definition covers scope, ordering, and filter combinability adequately. It is thin on the shape of the returned deals beyond the ordering and the merchant_verified flag, which leaves the agent guessing about result size and payload fields.

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, and the description adds genuine meaning on top: filters are optional (all four are non-required) and combinable (AND semantics across country/category/discount/time). That AND-combination rule is not stated anywhere in the schema and is exactly what an agent needs to build a multi-filter call.

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 gives a specific verb and resource ('List currently active flash-sale deals') plus the data source ('Heartly merchants') and default ordering ('sorted by ending soonest'). It does not explicitly contrast itself with search_deals_by_category, so an agent must infer that the difference is 'active only' vs 'search by category'.

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?

'Filters are optional and combinable' tells the agent it can call with zero arguments and stack filters, which is useful context. However, it never says when to prefer this tool over search_deals_by_category or get_deal_by_id, and there are no exclusions or prerequisites named.

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