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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, and idempotentHint=false. The description adds valuable context beyond those annotations: the result page shows the seed that reproduces the draw, and 'the answer is a drawstoday.com link where the result is shown; the answer itself carries no result.' That output behavior is not encoded in annotations or schema.

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 purpose and main modes are front-loaded, and every sentence carries useful information. The long parenthetical enumeration of game codes is dense but necessary for parameter clarity, so the definition is appropriately sized though not maximally crisp.

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, the description must explain the return behavior, and it does: the answer is a drawstoday.com link and the result page carries the seed. It also covers both game and custom modes, set limits, and seed-based reproduction. The main remaining gap is minimal guidance on error or fallback cases, but the core call semantics are complete.

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 88%, so the baseline is 3. The description adds meaning by expanding every game enum code with its real-world lottery name and notes (e.g., 'megamillions (Mega Millions (USA, matrix since 2025-04-08))'), and by explaining the custom format fields (count, min, max, extra_count, extra_max) and seed reproducibility. That goes beyond the raw schema enum values.

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?

The description states a specific action ('Random numbers for a lottery game') and resource, and mentions the 1-to-10 sets limit and named-game/custom modes. It does not explicitly contrast itself with siblings like check_ticket or get_draw, so it falls short of full sibling differentiation.

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 description explains the two primary usage modes ('either name a game ... or give your own format with game "custom"'), which implies when each parameter path applies. However, it gives no explicit when-to-use guidance versus check_ticket, get_draw, or other siblings, and no exclusions or prerequisites are stated.

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