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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description still adds real context beyond that: the response includes labeled house advertisements, and days that were removed or never existed are unavailable rather than returning empty data.

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, subject and selector front-loaded, with the availability caveat second. Nothing is padding, though the house-advertisement detail is a slightly tangential insertion.

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 an output schema present, return values need not be described, and the description covers scope, the date selector, and the failure mode. Complete enough for a one-parameter read tool, with only the sibling-routing guidance missing.

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% and the single 'day' parameter is fully documented in-schema (UTC, YYYY-MM-DD). The description's 'by date' and 'settled' wording reinforces the schema but adds no format or semantics the agent does not already have.

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 (read) and resource (one settled public Spotlight) plus the selector (by date), which cleanly separates it from get_current_spotlight and list_spotlights by implication. It stops short of naming those siblings, so the differentiation is inferential rather than explicit.

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 'settled ... by date' and the note that removed/missing days are unavailable, which tells the agent this is a historical, single-day lookup. However it never says when to prefer this over get_current_spotlight or list_spotlights, so the agent must infer the routing.

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