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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds meaningful context beyond that: it returns screen/button/field-level steps, performs no action itself, and requires a separate browser tool to execute. It also explains that no official MassageBook API exists, which justifies the tool's approach.

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 sentences, front-loaded with the core purpose and execution handoff. The final sentence about MassageBook's lack of an API is somewhat tangential but justifies why this tool exists, so it still earns its place.

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?

With no parameters and no output schema, the description is nearly complete: it says what the tool returns (step-by-step screens, buttons, fields), that it performs no action, and how to proceed afterward. The only minor gap is the exact return format (structured text vs. JSON), but for a guidance tool this is 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?

The tool takes zero parameters, so the baseline is 4. The description does not need to explain parameter semantics, and it does not waste space doing so.

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 states a specific verb and resource: produce step-by-step instructions for booking an appointment in MassageBook. It distinguishes itself from the browser execution tools by saying it 'opens nothing by itself' and pointing to cotlet_browser_* for execution. The lead sentence 'Book appointment...' is slightly misleading since the tool only returns guidance, but the following sentence corrects it.

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 gives clear context for when to use it: to get instructions, then use the cotlet_browser_* tools in the MassageBook Cloud Browser to perform the booking. It does not explicitly exclude or name sibling tools like massagebook_reschedule_appointment, so it falls short of a full when/when-not/alternatives statement.

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