Children of one layer

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the useful 'direct children' and 'cheap' performance context, but does not describe recursion behavior with depth, response format, or other runtime traits beyond the schema.

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 with no wasted words; the core action and scope are front-loaded, and the guidance about cheap traversal is packed into the second sentence.

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 read-only, simple listing operation with fully documented parameters and a readOnlyHint annotation, this description is nearly sufficient. It does not explain return shape, but the tool's purpose is simple enough that 'direct children' plus the schema gives an agent what it needs.

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 description coverage is 100%, and both nodeId and depth are already documented there. The description's 'by id' and 'direct children' wording adds slight clarification but does not significantly extend the schema's parameter semantics.

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 and resource: 'direct children of one node, by id.' The phrase 'the cheap way to explore a page a branch at a time' also distinguishes it from tree-wide navigation tools like figma_get_tree.

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 description gives clear usage context — use this to traverse a page incrementally branch by branch — and implies it is cheaper than fetching a full tree. It does not explicitly name alternatives or exclusion conditions, so it falls 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.