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

Annotations already declare readOnlyHint=true, so the safety profile is known. The description adds value by detailing the return payload (title, body, author, reviewer, citations, metadata) and scoping to a single article, which helps the agent understand what to expect. No contradictions found.

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 with no wasted words. The first sentence states the core action and target; the second lists the return fields. Information is front-loaded and every word 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?

For a simple single-parameter fetch tool, the description fully explains what it does and what it returns. The absence of an output schema is compensated by explicitly listing the return fields. No gaps are apparent.

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% for the single parameter 'slug', which is described as 'Article slug.' The description repeats the 'by slug' concept but adds no extra format, pattern, or examples. Since the schema fully covers the parameter, a baseline of 3 is appropriate.

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 clearly states the tool fetches a single article by slug, using a specific verb ('Fetch') and resource ('article from Psychiatry for Kids'). This distinguishes it from sibling tools like list_articles and search_articles, which operate on collections or queries.

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 implies usage: use when you have a specific slug to retrieve an article, as opposed to listing or searching. It gives clear context but does not explicitly mention alternatives or when not to use it. Given sibling names, the intended usage is inferable.

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