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

With no annotations, the description carries the full burden and does so: it declares the tool read-only, discloses that it returns aggregates only and not entries, explains the time-weighted ticket mechanics (buying at the close yields no tickets, locked tokens count), and states that the beacon round is emitted only after the list is frozen so the number cannot be known in advance. That is unusually rich behavioral context for a read tool.

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?

The what-it-returns summary is front-loaded in the first sentence, and the follow-on sentences each add decision-relevant information (weighting, beacon, totals-only, frozen-list alternative). The mechanical explanation of ticket weighting and beacon timing is longer than strictly needed for invocation, which keeps this short of a 5.

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?

No input parameters, no annotations, and no output schema, so the description must supply everything an agent needs, and it does: field inventory, semantics of the numbers, fairness/integrity guarantees, read-only status, and where the detailed data lives instead. Nothing material is left unstated.

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?

The tool takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate. It does not discuss defaults or scoping arguments because none exist.

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?

Opens with a precise verb+resource ('The public state of the holder raffle') and then enumerates the exact fields returned: open/closed status, window, weighted ticket total, wallet count, prize, and claim grace period. Nothing in the sibling list overlaps, and an agent can tell exactly what this tool produces without opening a schema.

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?

It clearly frames when the tool is the right source ('This returns totals only') and explicitly routes the agent elsewhere for per-wallet detail ('Once entries close, the frozen list ... is published at /api/raffle/entries?drawId=<id>'). It stops short of stating prerequisites or the inverse condition (e.g., what to call before entries close), so it is clear context rather than a full when/when-not rule set.

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