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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed world), so the bar is lower. The description adds operationally useful facts the annotations lack: the 400-entry cap, the whole-library default, and the indented output shape.

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?

Three tight sentences, front-loaded with what the tool returns and its scope, then usage, then the cap. No filler; the docs link is the only boilerplate.

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 output schema, the description does state the return format (indented outline) and the cap, which is the key operational caveat. It omits what happens on truncation at 400 entries and any ordering guarantees, but is otherwise sufficient for a read-only, closed-world tool.

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?

Schema coverage is 100%, so path/depth/locale semantics and defaults are already documented in the schema. The description restates the whole-library default and depth scoping but adds no syntax or edge-case detail beyond it.

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?

Specific verb+resource: an indented outline of the library tree beneath a path, with scope (default whole library) and depth. It implies a read-before-explore role but does not explicitly differentiate itself from list_topics or get_planned_subtree, which also enumerate tree structure.

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?

"Useful to understand how a domain is organized before reading pages" gives a clear moment to reach for this tool, implicitly routing the agent away from get_page. It stops short of naming sibling alternatives (list_topics, get_planned_subtree) or stating exclusions.

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