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

Annotations already establish this as a safe read (readOnlyHint, destructiveHint=false), but the description adds real behavioral context the annotations cannot: the quota applies to distinct sites returned rather than calls, calls are uncapped, and the tool is free. That quota semantics is exactly the kind of non-obvious trait this dimension rewards, though it doesn't say what happens once the allowance is exhausted.

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 compact, front-loaded with the returned payload, and every sentence carries information. Minor redundancy remains: 'how much allowance is left' is restated in the longer sentence about distinct sites and the monthly allowance.

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 input parameters, no output schema, and annotations covering the safety profile, the description carries the return-value burden and does so adequately by naming plan, permissions, and quota. It could go one step further on return shape, but nothing essential for invoking the tool is missing.

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. Baseline 4 applies.

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 enumerates exactly what is returned — plan, granted permissions, and remaining site quota — so the resource is unambiguous. It lacks a clean verb+object opening ('What this connection can do' is indirect), but the concrete payload list makes it easy to distinguish from siblings like find_sites or list_watches.

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?

'Worth calling before a large query' gives an explicit situational trigger, and 'Calls themselves are not capped... Free' clarifies the cost so an agent can call it liberally. There is no explicit when-not guidance or named alternative, so it stops 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.