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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered structurally. The description's added value is the return shape — folder paths plus note counts — which is genuinely useful since there is no output schema. It says nothing about ordering, empty-folder handling, or nesting depth, so it adds some but not rich behavioral context.

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?

Two short sentences, zero filler. The result shape comes first and the follow-up routing second, which matches how an agent would read it.

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 tool with no output schema, this covers what the call returns and what to do next. Minor gaps remain around ordering and whether paths are hierarchical or flat, but nothing needed to invoke it correctly 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 are no parameter semantics to explain; baseline 4 applies. The description correctly implies a no-argument call by not mentioning any inputs.

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?

Describes the resource (the user's note folders) and the shape of the result (paths like "Projects/Alpha" with a note count per folder). It is also implicitly contrasted with list_notes, so an agent can tell the two apart. It stops short of a clean verb-first statement such as "List all folders," relying on the tool name for the action word.

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?

The second sentence gives explicit routing: take the returned path and pass it to list_notes to see folder contents. That is a concrete when-to-use-this-and-what-next instruction. It lacks an explicit exclusion (e.g. when to prefer list_tags or search_notes), which keeps it off a 5.

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