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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description still adds real value beyond them: the 24-hour window, that entries are live and individually playable, and that it takes no arguments. It does not say whether this replaces or overlays the current UI view, which is the one behavioral detail still missing.

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?

Three short sentences, each carrying a distinct payload: what is shown, when to use it, and the argument situation. The scope (24 hours) is front-loaded and there is no 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 no-argument UI tool with full annotation coverage and an output schema, the description covers purpose, trigger and input expectations adequately. The only unaddressed point is how opening the tray interacts with the current view, a minor gap given the tool's simplicity.

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?

Zero parameters, so the baseline is 4. The description reinforces this with 'Takes no arguments,' which matches the empty schema and additionalProperties:false, but adds no further parameter nuance because there is none to add.

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+resource ('Show the person the generations') with a bounded scope (last 24 hours) and distinguishing traits (live, each one playable). It implicitly separates itself from list_generations by emphasizing a live playable display rather than a data listing, but it never names the sibling to make the contrast explicit.

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?

Explicitly states the triggering context: 'Use it when they ask what is running or what was just made.' That is clear when-to-use guidance, but it offers no when-not condition or named alternative (e.g. use list_generations for a data query instead of opening the tray).

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