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

Annotations already declare destructive=true, idempotent=true, readOnly=false. The description adds real context beyond that: the effect is scoped per assistant unless everywhere=true, the next personal request re-prompts sign-in, and 'it changes no bookings' pre-empts the false inference that a destructive tool mutates booking data.

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, all front-loaded: default behavior first, the everywhere escalation second, the invocation gate last. No filler and nothing repeated from the title.

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 single optional boolean with no output schema, the description covers default scope, escalated scope, re-authentication consequence, invocation condition, and side-effect boundary. Nothing needed to call it correctly 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 coverage is 100% and the schema already explains that everywhere ends every sign-in of the account with a default of false. The description restates the same semantic in prose, adding emphasis but no new format or edge-case 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?

States a concrete verb and resource ('Signs the user out of Awning') and immediately narrows scope: 'in this assistant only' versus 'every assistant, device and browser'. An agent can tell exactly what this does and how far it reaches without opening the schema.

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 restricts invocation: 'Use it only when the user asks to sign out', which is a clear when-to-use gate. It doesn't name alternatives, but no sibling tool offers competing sign-out behavior, so the gap is minor.

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