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

The description frames the tool as a pure read ('Get a ... proverb'), but the annotations declare readOnlyHint=false and destructiveHint=true, so these two signals directly conflict. Even setting that aside, the description reveals nothing about whether the proverb is cached per day, how 'random' selection works despite idempotentHint=false, or what the openWorldHint means here.

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?

This is one sentence, with the action front-loaded and the return content appended; there is no padding. It could be tightened slightly, and the parenthetical name 'Ilụ' is helpful context rather than filler.

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 zero-parameter, output-schema-less tool, the description is almost adequate: it tells the agent what comes back (proverb, origin, meaning). However, it omits the randomness/daily-cache behavior and leaves the safety profile unresolved against destructiveHint=true, which is material for a tool an agent may call repeatedly.

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, so the baseline is 4; there is nothing for the schema to document and nothing for the description to clarify. The description correctly implies a no-argument call by describing a single fixed retrieval.

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 verbal phrase 'Get a curated, authentic Igbo proverb of the day (Ilụ)' names a specific verb and resource, and it also previews the payload ('folkloric origin and philosophical meaning'). It never distinguishes itself from the sibling tool `search_proverbs`, so an agent cannot tell from this sentence alone which one to pick.

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 phrase 'of the day' implies that this tool returns a rotating pick, but the description never states when to use this tool instead of `search_proverbs` or `search_cultural_archive`, and it never says whether the agent should call it once per session. There is no when-not guidance and no mention of the alternative.

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