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 fusion semantics and output artifacts. However, it advertises 'AI narrative' without disclosing the Gemini API-key dependency that the includeNarrative parameter documents, which could mislead an agent into expecting the narrative to always succeed. Not a contradiction, but a modest disclosure gap given the output feature is prominent.

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 sentences (English plus a Japanese translation) with the core purpose front-loaded and no filler. The bilingual duplication costs some economy, but it is reasonable for a Japan-market tool and every sentence earns its place.

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?

An output schema exists, so return-value documentation is unnecessary. The description covers the fusion model and output artifacts. Missing pieces: no usage guidance versus siblings, no disclosure of the narrative API dependency, and no clarification of weight semantics (e.g., whether weights must sum to 1). Adequate for a schema-rich tool but not complete.

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%, with every parameter documented including enums, ranges, defaults, and bilingual notes. The description's mention of the 5 axes merely restates what the weights object already documents. It adds no param-level meaning beyond the schema, so the baseline 3 for full coverage applies.

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 states a specific verb ('fuse') and a concrete resource (5 named axes into a 0-100 score), and previews the output artifacts (radar, tier, peer comparison, AI narrative). It is clear what the tool does. However, with 30+ siblings it never names what it is not — an agent cannot readily tell it apart from assess_property_risk, forecast_land_price_trend, or cross_analyze_real_estate_market without opening schemas.

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?

No when-to-use guidance, no exclusions, and no alternative routing is provided. Given the large sibling set and overlapping analysis tools (assess_property_risk, cross_analyze_real_estate_market, compare_prefectures), an agent has no signal about which tool fits a given query. The purpose is stated, but the choice context is entirely absent.

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