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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral context: the returned content is Markdown, and the footnotes contain primary-source citations. However, it doesn't mention potential absence of the article, error behavior, or whether the full text is always available. With annotations covering safety, a 3 is appropriate.

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?

Three sentences, each earning its place: the first states the core function, the second gives usage guidance, and the third adds a useful behavioral detail about footnotes. No wasted words.

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 simple read-only tool with one parameter, the description is nearly complete. It covers what the tool does, when to use it, and what the output contains. The only minor gap is not describing behavior when the slug doesn't exist, but the annotations and schema already cover the essential context.

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%, so the schema already documents the slug parameter. The description adds the example 'b-type-opening-guide' and notes that the slug comes from search_articles results, which is helpful but not extensive. Baseline 3 is correct when the schema does the heavy lifting.

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 ('取得する'), a specific resource ('fukushi.ai の公開記事'), and the retrieval key ('slug で指定して全文（Markdown）'). It also explicitly distinguishes itself from the sibling tool search_articles, making the tool's purpose unmistakable.

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 explicitly names the alternative (search_articles) and gives the condition for choosing this tool: when the excerpt from search_articles is insufficient to grasp procedures or tables. This is clear when-to-use guidance with a named alternative.

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