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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds two real facts beyond that: results are gated on Storylines having checked stats, and the returned team names are canonical identifiers to reuse downstream. It says nothing about ordering, result volume, or what happens when no games qualify.

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, both front-loaded, with no filler. The only minor cost is the slightly awkward framing 'Upcoming games Storylines has checked stats for', which reads as an inverted clause rather than a clean statement of purpose.

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?

There is no output schema, yet the return shape is only hinted at via 'team names exactly as returned'. An agent knows the input contract and the downstream team-name rule, but not what fields come back per game (times, IDs, status), which matters for a scheduled-events endpoint.

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 baseline is 3, but the description adds meaning the schema does not: the 'day' is a US Eastern date, which disambiguates timezone for a date-only string field. It also reinforces the one-sport-per-call constraint, complementing the schema's example keys.

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?

Names a specific resource and scope: upcoming games for one sport and one day, where the data is limited to games Storylines has stats for. The implicit verb (list/fetch) plus the 'checked stats' qualifier separates it from siblings like get_storylines_facts or get_predictions, though the description never names those siblings 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?

The sentence 'Use the team names exactly as returned when you ask for facts' implicitly describes a two-step workflow with get_storylines_facts, which is genuinely useful. However it never states when to prefer this tool over get_predictions, get_predicted_scores, or get_free_picks, and gives no exclusion conditions.

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