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

Annotations only give safety flags (readOnly=false, idempotent=false, destructive=false, openWorld=false); the description adds real context beyond them by disclosing the composite nature of the call and an example invocation syntax ("do 'sign mira Hello!'"). It does not say what the caller receives back or whether the stay has side effects like consuming time/energy, which keeps it from a 5.

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?

Two compact sentences, front-loaded with the core action, with no filler. The whimsical phrasing is characterful rather than wasteful, though the inline sign example slightly interrupts the flow.

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-output-schema tool, the description tells the agent what the visit entails and how to interact with the destination, plus where to find neighbours and how to return home. The only omission is any indication of what a visit returns or costs, but coverage is otherwise sufficient.

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?

With 100% schema description coverage, the baseline is 3. The description's example ('sign mira Hello!') loosely illustrates the name parameter, but the auth 'key' parameter and the required-name contract are already fully covered by the schema, so the description adds little semantic detail.

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 names the resource (a neighbour's house) and enumerates the composite actions it performs — look, say hello, sign the guestbook, dance — so an agent knows this is a multi-action visit tool, not a single primitive. It also names two siblings (neighbours, home) that cover adjacent needs, aiding disambiguation.

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 explicitly routes to alternatives: 'neighbours lists who lives near you and who's new; home walks you back.' That tells the agent when NOT to use visit, though it never states a positive trigger (e.g. 'use this when you want to drop in on a specific neighbour'), so it stops just short of full when/when-not guidance.

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