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

No annotations exist, so the description carries the full burden — and it does substantial work by detailing exactly which five data blocks come back, including the 50% threshold concept and the 2050 crossover set. It is implicitly a read-only lookup. It does not cover failure behavior for unknown town/industry names, which is the main remaining gap.

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 a one-line summary of the operation, then structured as ①–⑤ so an agent can scan the returned content. It is dense and reads as a long run-on sentence, but nearly every clause conveys real information about the payload rather than filler.

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 no output schema and no annotations, the description is the only source of return-value information, and it enumerates all five response sections in enough detail that an agent knows what it will get. Missing only edge-case behavior (invalid town/industry, the role of prefecture), which keeps it short of a 5.

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 100%, so the baseline is 3. The description adds some value by naming the accepted industry families (61 ALGO BIZ sectors vs. census small-classification names or 3-digit codes) and example sectors, but it says nothing about the optional prefecture parameter, which only the schema documents.

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 concrete verb and resource: takes one municipality and one industry and returns a single combined card, then enumerates the five sections returned (population projection, industry presence thresholds, prefecture labor stats, national cost-ratio sensitivity, and a ready-to-read sentence). This clearly distinguishes it from the single-axis siblings get_town and get_industry, though it never names them explicitly.

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 'town × industry in one card' framing implies when to prefer this over the single-axis lookups, and the accepted industry vocabularies are spelled out. However, there is no explicit 'use this instead of get_town/get_industry when you need both dimensions' statement and no guidance on when the optional prefecture parameter is required beyond a terse hint in the schema.

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