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 non-obvious domain behavior: curated families expose node_kind=codelist containers at root, and those codes act as parent_code filters. It does not, however, mention pagination or that 'limit' caps returned nodes.

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 tight sentences with no filler, and the core behavior (top-level vs. children) is front-loaded. The codelist quirk in the second sentence earns its place, though it could be split for readability.

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 an output schema present, return-value explanation is unnecessary, and annotations cover safety. The remaining gap is pagination/limit semantics and the meaning of classification_id, which are omitted across both schema and description for a 3-parameter 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 description coverage is 0%, so the description carries the full burden. It explains parent_code well (null = root, a codelist code = its options) but leaves classification_id and especially limit (default 200, max 500) entirely unexplained.

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 pairs a specific verb ('Browse') with a specific resource ('top-level nodes or immediate children'), making it clearly a hierarchy-navigation tool rather than a search or lookup tool. It is distinguishable from search_codes and get_code_definition by scope, though it never explicitly names an alternative to route against.

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?

Usage is implied through the parent_code workflow ('pass that code as parent_code to browse its options'), which tells an agent how to descend the tree. However, there is no explicit when-to-use vs. when-to-use-an-alternative guidance relative to search_codes, get_classification, or list_codelists.

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