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 genuine non-schema context: the tool opens nothing, returns screen/button/field level guidance, and hands off to the browser tools. The closing sentence about Mews's Connector API and the absence of an official MCP server adds no invocation value.

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 short and the key limitation ('opens nothing by itself') is stated early. The marketing framing ('from ChatGPT, Claude or any AI agent') and the API/MCP-server aside are filler that dilutes the operational content, and the second sentence is an awkward run-on.

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, no-output-schema instruction tool, the description should say what the returned guidance covers and how it is tailored — it only gestures at 'screens, buttons, fields'. It also never addresses how generic guidance applies to a specific reservation given there is no reservation parameter, leaving an agent unsure what it will actually receive.

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 schema has zero parameters and 100% description coverage, so parameter semantics are a non-issue and the baseline of 4 applies. The description does not attempt to explain how the guidance is scoped without a reservation identifier, which is the only real gap here.

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 does eventually make the actual behavior explicit — 'Returns how to do it in Mews step by step... and opens nothing by itself' — which is a specific and non-obvious purpose. However it opens with 'Add reservation note in the user's own Mews account', which reads as if the tool performs the action, directly at odds with the name/title being an action verb. An agent skimming the first clause would misclassify this as a mutation tool.

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 a workflow hint — 'then do it with the cotlet_browser_* tools in the user's Mews Cloud Browser' — so the sequencing is implied. It never states when to reach for this versus cotlet_app_guide or versus simply navigating to the reservation directly, and gives no preconditions for when these instructions are needed at all.

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