ndl_search_digital_open

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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHintfalse, so the safety profile is covered. The description adds value by clarifying the data set scope and licensing: only open-data records are included, and the wider collections are 'displayable, not redistributable'. This is useful behavioral context about what the tool can return, though it does not describe response format or limits.

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 compact and well-structured: a one-line purpose statement in Japanese, then a concise English explanation of the key scope constraint and licensing nuance. It front-loads the main action and does not waste words, though the language mix is slightly awkward for an English-first agent.

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 tool has an output schema and annotations cover read-only/idempotent behavior, the description’s main job is scoping and usage guidance. It handles scoping well and adds useful licence context, but it leaves out any explicit guidance on when to choose this over siblings like ndl_search_books or ndl_search_all, and it does not mention pagination or result count controls (though those are in the schema). Overall it is adequate but not thorough.

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?

The tool description contains no parameter information. Context signals report 0% schema description coverage, so the description must compensate but does not. The nested schema fields have some descriptions, but the top-level 'params' parameter is undocumented in the description, leaving an agent to delve into the $ref to construct a query. The description's licence discussion gives no help with the many search fields.

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 clear verb and resource: 'Search 国立国会図書館デジタルコレクション（オープンデータ）', reinforced by the annotation title 'Search NDL Digital Collections (Open Data)'. It distinguishes from the wider Digital Collections by explicitly saying 'The open-data set only', so an agent can tell this tool is scoped to the open subset. It does not name sibling search tools, but the scoping qualifier differentiates enough.

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 gives context about when to use this tool: it searches only the open-data set, and the wider collections are explicitly excluded. It does not name alternative tools or say 'use X for the wider collections', but the scope limitation clearly implies this tool is for open data. The licence discussion adds context about the data set, but no explicit when-not-to-use or alternative routing.

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