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

With no annotations, the description carries the full burden and does well: it discloses the TTL bounds (1-24h), the default (8), the clearing mechanism (0), and the observable effect ('shows as available (declared)' distinct from the presence window). It does not mention permission/auth requirements or interaction with the presence state on expiry, so it is not fully complete.

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 tight sentences with no filler; the core behavior and default are front-loaded and the clearing instruction lands last where it is easy to find. The term 'square' is domain jargon that is left unexplained, which slightly hurts immediate comprehension.

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 two-parameter, zero-required, no-output-schema tool, the description covers the key facts an agent needs: duration default, bounds, display effect, and how to undo the declaration. Absence of auth/permission notes and any mention of how long the declared state persists relative to presence is a minor gap.

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 already 100%, so the baseline is 3, and the description adds value beyond the schema by stating the default value of 8 hours, which the schema does not specify. The '0 clears' semantics is also restated here more prominently than in the schema, though little else is added.

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 gives a concrete verb+resource ('Declare availability') and specifies the scope ('for the next N hours'), so the agent knows exactly what the call does. It also implicitly distinguishes itself from presence-read siblings by noting the state is 'separate from the 5-minute presence window', though it never names heartbeat or get_presence directly.

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?

It conveys the intended use case ('no polling daemon required') and gives a clear alternative action ('Pass ttl_hours: 0 to clear'), which is a genuine when-to-use signal. It stops short of explicitly stating when NOT to use it or pointing at sibling tools like heartbeat.

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