Read one article

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

The description adds behavior beyond annotations: it discloses the 404 masking for unauthorized access, the publishable key restriction, the required `articles:read` scope, and the fact that nothing is changed. These are not covered by the readOnlyHint, openWorldHint, or idempotentHint annotations, so it enriches the behavioral profile.

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 front-loaded with the core action and return value. It is mostly concise, but the sentence about 'no disclosure reason that governs cross Site access' is somewhat convoluted, and 'Read only. Nothing is changed.' duplicates annotation info. Still, it remains tight and readable.

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?

The tool is simple (read one article by ID), and the description covers the return value, auth requirements, the 404 edge case, and the safety profile. No output schema exists, but the description adequately conveys what the tool returns. The `fields` parameter is documented in the schema, so the description does not need to repeat it.

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%, and both `id` and `fields` already have clear descriptions. The tool description does not add extra meaning to the parameters; it only mentions `content` as part of the return, which is not parameter-specific. Thus, baseline 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 begins with 'Read one article,' which clearly identifies the verb and resource. It further specifies it 'Returns the full article including `content`,' distinguishing it from list_articles, create_article, and other sibling tools that handle multiple articles or mutations.

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 provides clear context: this is for reading a single article by ID. It also notes a specific condition (publishable key can only read published articles, otherwise 404) and required scope. However, it does not explicitly mention alternatives like list_articles for fetching multiple articles, so it falls short of a 5.

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