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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent write. The description adds real behavioral detail: the 80-character name cap and that card_ids are persisted as their phrases. It does not say whether saving a duplicate name overwrites, whether saved quizzes consume storage limits, or whether the underlying cards/SRS state is untouched.

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 purpose before the parameter notes, and no filler. The 'spec:'/'name:' label style is terse to the point of being slightly cryptic, but nothing is wasted.

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 2-param mutation with a nested object and no output schema, the description covers inputs well but not outputs – it implies an id exists (used as saved=id) yet never says the saved quiz's identifier is returned, nor what happens on a name collision or an invalid spec field.

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 0% and spec is an opaque nested object with additionalProperties, so the description must carry the load – and it does, enumerating the accepted fields (type, source, size, mode, tag, terms, card_ids), the phrase-storage rule for card_ids, and the name length limit. It still omits value domains for type/source/mode, so it is strong but not complete.

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 ('Save a quiz') plus scope ('of the active language') and immediately ties it to the sibling that consumes it, 'quiz_start(saved=id)'. An agent can distinguish this from quiz_start, quiz_delete, and quizzes without opening any 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?

Explains the intended lifecycle – save now so the quiz can be re-run later via quiz_start(saved=id) – which is genuine when-to-use guidance and names the alternative path. It stops short of saying when *not* to save (e.g., one-off quizzes) or how it relates to quiz_delete.

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