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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, so the safety profile is covered; the description adds genuinely useful context by stating it 'opens nothing by itself' and that execution requires separate browser tools, which prevents an agent from assuming side effects occurred. The API-access note adds a real constraint (support email required). It doesn't describe the shape or granularity of the returned instructions, which keeps it off 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?

The most important facts — what is returned, that nothing is opened, and which tools do the actual work — are front-loaded in the first two sentences. The final sentence about the official API is longer than it needs to be ('checked 11 Nov 2026') but it earns its place by steering the agent away from a dead-end integration path.

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 tool, the description covers what an agent needs: the return content, the absence of side effects, and the follow-up tool family. It would be stronger if it specified that the response is textual guidance rather than a structured payload, but nothing essential is missing for correct invocation.

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 there is nothing for the description to disambiguate; the baseline for a parameterless tool applies. The description does explain what the caller gets back (step-by-step screens, buttons, fields), which is the only input-adjacent semantics that matters 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 explicitly states the tool's real output: 'Returns how to do it in Club OS step by step (screens, buttons, fields)', which corrects the potentially misleading name/title that suggests the tool performs the check-in. It also distinguishes itself from the execution path by naming the 'cotlet_browser_*' tools as the way to actually do it. The only weakness is that the first clause still reads like an action verb before the clarifying sentence lands.

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 clear two-step workflow: call this to get instructions, then execute with the cotlet_browser_* tools in the user's Club OS Cloud Browser. It also addresses the obvious alternative (Club OS's official API) and explains why it is not usable here — credentials require emailing support. No explicit 'do not use this for X' exclusions among the many siblings, but the routing is otherwise unambiguous.

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