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

With no annotations provided, the description carries the burden of disclosing behavior. It does reveal the recursive nature of the response ('its children, and their children, ...') and the content structure ('each with a `code` and a `text` description'). It also adds practical context about verifying the suitability of a heading. It does not mention error handling, depth limits, or rate limits, but for a read-only tree query, the key behavior is well conveyed.

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?

The description is two sentences long, front-loaded with the primary action, and every clause serves a purpose. There is no fluff or repetition of schema information.

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?

Given the presence of an output schema and 100% schema description coverage, the description need not explain return values or parameter syntax. It provides the essential tree semantics and a practical use case, which is sufficient for an agent to select and invoke the tool appropriately. It could mention potential edge cases, but the overall context is well covered.

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%, so the schema already fully documents both parameters (`code` and `lang`). The description adds some context for `code` by linking it to the use case (checking a heading as `query.product`), but it does not add any meaning for `lang`. Per the rubric, the baseline for high schema coverage is 3, and the marginal addition does not elevate it beyond that.

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 clearly states the tool's function with a specific verb ('Return') and resource ('Combined Nomenclature sub-tree rooted at `code`'), and explicitly describes the recursive structure (children and their children). It also distinguishes itself from siblings by explaining its use case: checking if a heading is a clean match or bundles sub-products.

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 provides explicit when-to-use guidance: 'Use this to see whether a heading you're about to use... is actually a clean match...' This gives clear context for invoking the tool. However, it does not explicitly name alternatives or state when not to use it, which keeps it from a perfect 5.

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