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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context beyond that: 'no sign-in needed' discloses the authentication requirement, which the agent cannot infer from the annotations.

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 tight sentences with zero filler. The content scope is stated first and the actionable directive ('Read this first') follows, giving appropriate front-loading.

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 zero-parameter, read-only static guide with no output schema, the description conveys enough: it says what the guide contains (step-by-step booking and cancellation instructions) and that no auth is required. Only the shape of the returned content (markdown vs. structured steps) is left unspecified, a minor gap at this complexity.

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 takes zero parameters and the schema is empty with additionalProperties=false, so there is nothing to document; baseline for a parameterless tool is 4. The description correctly does not invent parameter talk.

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 precisely (the booking guide) and enumerates its content: how to book a call with Patrick Vieira and how to cancel one. It implicitly contrasts with the book_meeting and cancel_booking siblings by framing itself as the instructional content about those actions, but it never names them explicitly, so it falls just short of full sibling differentiation.

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?

'Read this first' gives an explicit precedence rule, telling the agent to consult this guide before attempting booking or cancelling. It stops short of naming the concrete alternatives (book_meeting, cancel_booking) or stating when the guide is not needed, so it is clear context without full when/when-not coverage.

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