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

With no annotations, the description carries the burden and does meaningful work: it discloses the uniqueness constraint on name, the 4-level nesting limit, and that items are persisted as custom links rather than references, plus the menuId binding contract. It omits auth/permission requirements and side effects, but the material behavioral facts an agent needs are present.

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?

Front-loaded with the core action, then constraints, then the sibling pointer and the prerequisite rule. Dense but every clause carries information; the "Rules:" fragment is slightly telegraphic but not wasteful.

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?

An output schema exists so return values need no explanation, and the schema documents both parameters. Combined with the binding semantics and prerequisite call, the definition is sufficient for correct invocation; only deeper behavioral notes (permissions, idempotency) are absent.

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 already 100%, so 3 is the floor, but the description earns above baseline by clarifying that name must be site-unique, that items are custom links nested up to 4 levels, and how menuId binding relates to the created menu.

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?

States a specific verb (Create) and resource (navigation menu) and adds differentiating detail: unique name, items nested to 4 levels, stored as custom links, and consumed by header/footer blocks via menuId. An agent can separate this from list-menus/update-menu/delete-menu without opening schemas.

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?

Explicitly names an alternative and the condition that selects it ("list-menus first to reuse one") and adds a hard prerequisite (read the site-assets-contract skill doc before the first call). It stops short of full when/when-not framing but the routing guidance is concrete.

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