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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false. The description adds little beyond that: it does not explain return behavior, and its mention of weather and what is open adds confusion for a zero-parameter tool rather than useful behavioral context.

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 first two sentences redundantly restate the tool name and title, and the third sentence is a long description of a different operation. It is not bloated, but it is not front-loaded or efficient.

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?

With no output schema and no parameters, the description should clarify what listing vibes returns and when to choose it over spinmyday_spin_my_day. Instead, it describes spinning a full day, leaving the tool's actual output and role unclear.

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 has zero parameters and the schema is empty with 100% description coverage, so there is no parameter semantics for the description to clarify. Baseline 4 is appropriate.

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 name is list_vibes, but the description first restates the app/title ("Spin My Day. The vibes you can ask for.") and then says "Spin up a full day out (morning, lunch, afternoon, dinner, evening) around the weather and what is open...," which describes the spinmyday_spin_my_day sibling rather than listing vibes. It never clearly states that this tool returns the available vibes.

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?

There is no when-to-use guidance, no when-not-to-use guidance, and no mention of the sibling spinmyday_spin_my_day. The only implied usage is the vague phrase "The vibes you can ask for."

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