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

The annotations cover the safety profile (readOnly, non-destructive, non-idempotent, closed-world), and the description adds the non-obvious part structured metadata cannot: the return value is a drawstoday.com link and the answer text contains no result. That is exactly the kind of surprise an agent needs disclosed before calling.

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 sentences, front-loaded with the core operation and constraints, then the return-format caveat. No filler; every clause carries information.

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, and the description supplies the missing return semantics (a link, no inline result) along with all parameter bounds an agent needs. Nothing essential to a correct call is absent.

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 only 33%, but the description compensates for the two undocumented parameters by stating count and sides ranges and the default six-sided die. Only seed has a schema description; the description doesn't restate it, which is fine.

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 gives a specific verb and resource (roll dice) and states the exact domain: 1-100 dice, 2-1000 sides, default one d6. This clearly separates it from flip_coin and random_integer in practice, but it doesn't name any sibling or draw an explicit boundary.

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 the rolling semantics, and the seed sentence explains that reproducing an earlier draw is how a draw is verified. However, that guidance duplicates the schema's seed description, and there is no explicit statement of when to prefer this tool over random_integer or flip_coin.

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