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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds genuinely non-structured behavior: the date range window (30 days back to 7 days ahead) and the timezone default of Australia/Sydney, both of which affect whether a call succeeds or returns the expected day.

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?

Front-loaded purpose sentence, then return summary, then workflow hint, then a clean Args block. Every line earns its place; the timezone guidance is slightly wordy but justified by the overseas-racing edge case it prevents.

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?

An output schema exists, so explaining return fields is supplemental rather than required, and the description still summarizes them. Combined with complete parameter guidance, range limits, and workflow placement, an agent has everything needed to invoke this correctly.

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 0%, so the description carries the full burden and does so: 'date' gets format YYYY-MM-DD plus a valid range, 'race_code' gets all three enum values and the default, and 'timezone' gets IANA format, examples, and the default. This is meaning an agent cannot get from the bare schema.

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 and resource with scope ('List race meetings for a date') and adds that it returns venue name, race count and status. It positions itself as the discovery entry point, which implicitly separates it from card/results/profile siblings, but it never names an alternative tool 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?

'This is typically the first call to make — use it to discover what tracks are racing on a date' gives clear when-to-use context and workflow position. It stops short of stating when-not-to-use or naming the downstream siblings (get_race_card, get_race_results) that this call feeds.

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