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

Annotations already declare readOnlyHint=true, idempotentHint=true, and non-destructive, and the description is consistent with that by stressing it opens nothing by itself. It adds genuinely useful context beyond the annotations: the return is step-by-step procedural guidance, and there is no public API so a browser is required. It does not describe the exact shape or length of that guidance, which is the remaining gap.

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 core constraint (returns instructions, opens nothing) is front-loaded and earns its place. However, "from ChatGPT, Claude or any AI agent" is filler, and "CoachingPortal's official API: CoachingPortal publishes no public API" is redundantly phrased and could be stated in one clean clause.

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 tool with no output schema, the description covers what matters: what it returns, that it has no side effects, and which tool family performs the actual action. What is missing is minor — whether the guidance is exhaustive per screen and whether follow-up calls are needed for multi-step flows.

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?

With zero parameters the baseline is 4; the empty schema is self-explanatory. The description could usefully note that the target client must therefore be identified in conversation rather than passed as an argument, since that is non-obvious for a per-client action.

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 a specific verb and resource ("Set client active") and clarifies the tool's real nature: it returns step-by-step guidance rather than performing the change. It does not explicitly contrast itself with the many sibling `coachingportal_set_*` tools, but the guidance-vs-execution framing makes its role distinguishable.

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 usage flow clearly: call this to get screens/buttons/fields, then execute with `cotlet_browser_*` tools in the Cloud Browser, and notes it "opens nothing by itself." It gives no explicit when-not condition or named sibling alternatives, which keeps it 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.