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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: it returns screens/buttons/fields as text, opens nothing by itself, and must be followed by browser-tool execution. The API-gating paragraph is background justification rather than tool behavior, 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?

It is front-loaded correctly, with purpose and workflow in the first two sentences. But the final third is a digression about Mariana Tek's official API, partner ToS, and a checked date ('checked 11 Oct 2026') that does not change how an agent invokes this tool and dilutes the actionable instructions.

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 guidance tool with no output schema, the description covers what it returns (step-by-step screens, buttons, fields), what it does not do (opens nothing), and what to do next (cotlet_browser_* tools). The only thing an agent might still want is the exact shape/scope of the returned instructions, but that 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?

The tool takes zero parameters and the schema is fully closed (additionalProperties: false), so there is no parameter semantics to explain; the 0-param baseline of 4 applies. The description appropriately adds no parameter detail that would be redundant.

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 first sentence names a specific verb and resource ('Cancel reservation in the user's own Mariana Tek account') and the second immediately corrects the implication of the name by stating it 'Returns how to do it in Mariana Tek step by step (screens, buttons, fields) and opens nothing by itself.' An agent can tell this is a guidance tool rather than a mutation, though the leading 'Cancel reservation' phrasing still pulls toward the wrong expectation until sentence two.

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 states the workflow explicitly: call this to get step-by-step instructions, 'then do it with the cotlet_browser_* tools in the user's Mariana Tek Cloud Browser.' That names the alternative path an agent must take. It gives no when-not guidance and does not distinguish itself from mariana_tek_book_reservation or other account-scoped siblings, so it falls short of a 5.

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