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

Annotations already cover the safety profile (readOnlyHint, destructiveHint=false, openWorldHint), so the bar is lower, and the description adds a genuinely non-obvious inclusion policy: offers with no stated end date are excluded. That materially changes how an agent should interpret empty or partial results, which the schema does not convey.

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 short sentences with no filler, and the exclusion rule is placed last as a qualifier after the usage trigger. Slightly weak front-loading in that the first sentence leads with usage rather than stating the core action.

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 one optional parameter at full schema coverage, an output schema to explain returns, and annotations carrying the safety profile, the description only needed to add usage context and any interpretive caveat — both of which it does. Naming the nearest sibling alternatative is the only notable omission.

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% and the single 'days' parameter documents its default (30) and bounds (1-365). The description adds no additional meaning about the lookahead window, so the baseline of 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?

The description never explicitly states the verb+resource ('list bonuses ending within a window'); that meaning is carried almost entirely by the name and title. The phrase 'a user asking what is about to end' implies the scope but gives no differentiation from sibling search_bonuses, which an agent could plausibly pick instead.

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?

'Use when timing matters — a user asking what is about to end, or whether to act now' gives a concrete situational trigger that clearly separates this from a general lookup. It stops short of naming alternatives (e.g. search_bonuses) or stating when NOT to use it.

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