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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds that this is a static master list of codes and names — useful context — but says nothing about whether the list is stable/cacheable, how many entries it returns, or the shape of each entry.

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 compact sentences (EN/JA) with the purpose and the downstream usage front-loaded; nothing is padded or redundant.

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 zero-parameter reference tool with no output schema, the description covers what the rows contain (codes and names) and what they are for. The only gap is the exact return container (array vs map) and entry count, which an agent must discover by calling it.

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?

Zero parameters, so the baseline is 4. The description correctly adds no parameter claims and instead explains how the returned codes are consumed by other tools' sector filters, which is the only semantic detail that matters here.

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 resource (TSE 33-sector master list) with its contents (codes and names), which is immediately distinguishable from data-fetching siblings like get_quote or get_sector_performance. An agent knows this is a reference/lookup tool, not a data query.

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 gives the intended use: the codes are meant to feed the 'sector' filter of other tools. That is clear positive guidance, but it does not name any actual sibling tool that accepts a sector parameter, nor state when-not to use it (e.g., for performance data use get_sector_performance).

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