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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so no safety disclosure is needed. The description adds genuine behavioral context beyond that: evening picks 'lean decaf' and the result is 'scored over Percolate's tasting profiles.' There is no contradiction with the annotations.

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 a single, well-paced sentence with no filler. It front-loads the core promise ('A coffee suggestion for right now') and every phrase contributes meaning.

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 read-only recommender with no required parameters and no output schema, the description covers the returned artifact ('a coffee suggestion'), the relevant inputs, and the scoring basis. It is slightly light on return-shape detail and does not mention edge cases like omitted inputs, but nothing critical is missing.

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 100%, so the schema already documents all three parameters fully. The description names the same three factors and adds only the evening-decaf behavior, which largely duplicates the time_of_day schema text; it provides no new parameter-specific semantics.

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 clearly states the tool returns 'a coffee suggestion for right now' and lists the deciding factors: time of day, mood, and brew method. It is specific enough to distinguish it from catalog-lookup siblings like search_coffees or get_coffee, but it does not explicitly name or contrast any sibling.

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?

'For right now' gives a clear temporal context for when the tool is appropriate, and the mention of time, mood, and brew method describes the intended scenario. However, it never says when not to use it or points to alternatives such as get_recommendations or dial_in_suggestion, so it stops short of full routing guidance.

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