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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real value beyond that: the 30-day default, ascending expiry ordering, the exact field set returned, and a data-quality caveat that 'listed' rows are not yet human-verified.

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 dense sentences, front-loaded with the window and ordering before the field list and caveat. The embedded field enumeration is compact; the quoted 'listed' term is slightly ambiguous but earns its place as a data-quality signal.

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, listing the returned fields (slug, name, provider, expiryDate, endsAt, daysLeft, url) is exactly the right compensation, and the paging reference covers volume. Minor gaps remain around paging defaults and the meaning of each hub value.

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 only 40%, and the description compensates partially by documenting the withinDays default of 30 and by pointing at shared filter/paging semantics. It leaves hub (an enum of seven categories), page, and limit unexplained beyond the schema's bare types and bounds.

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 the specific resource (offers whose free deal ends within N days), the default window of 30 days, and the sort order (soonest first), plus the returned fields. That temporal scoping distinguishes it from search_free_ai_offers and offer_history, though no sibling is named explicitly.

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?

Usage is implied by the deadline framing and the note that it mirrors the aifree.dev/calendar data and GET /api/v1/deadlines. There is no explicit statement of when to prefer this over offer_history or search_free_ai_offers, and no exclusions.

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