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

Annotations already cover read-only and non-destructive behavior, and the description adds the key behavioral trait: the answer is chosen at random from a fixed set of twenty responses. It does not contradict annotations; idempotentHint concerns side effects rather than deterministic output.

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 description is short and front-loaded with the essential behavior. 'Returns the answer' is somewhat redundant with the first sentence, and the source URL is ancillary, but neither significantly harms clarity.

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?

For a simple one-optional-parameter random tool with an output schema and safety annotations, the description is largely complete: it covers randomness, the answer set, and the input type. It does not say what happens if the optional question is omitted, but the schema already indicates it is optional.

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 schema description fully covers the single optional parameter, so the baseline is 3. The description adds no additional parameter-level meaning beyond repeating that the question is yes/no, which the schema already states.

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 opens with a specific verb ('Ask'), names the exact resource (Magic 8 Ball), and states the expected behavior: returning one of twenty classic answers at random. This makes it clearly distinct from sibling tools like coin flips or dice rollers without needing to compare schemas.

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 gives a clear use context—yes/no questions—which implies when the tool is appropriate. However, it does not explicitly mention alternatives such as hopi_yes_no_wheel or hopi_fortune_cookie, nor does it state when not to use this tool.

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