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

Annotations already cover readOnly/idempotent/non-destructive safety. The description adds useful behavioral context beyond those: it reveals that the structured API URL is 'paid' and that full Markdown is only available to 'CMS-authorized clients', which is an authorization nuance not present in the annotations. No contradiction with annotations.

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 concise sentences with no filler. The primary action and scope are front-loaded, and the second sentence adds a relevant authorization detail without bloating the description.

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, two-parameter tool with no output schema, the description covers the core behavior, the slug-based lookup, the paid URL return element, and the authorized Markdown option. It does not fully formalize the include_content flag or describe return structure, but it is largely sufficient for an agent to invoke the tool correctly.

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 0%, so the description must compensate for both parameters. It only hints at the include_content behavior through 'may also request full Markdown' and never explicitly names the parameter, its default, or the meaning of 'slug' beyond being the lookup key. This is only partial compensation for undocumented schema properties.

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 ('Retrieve') and resource ('public metadata and the paid structured API URL for one article'), with a clear lookup key ('by slug'). It is distinct from sibling tools like search_articles or latest_articles, which do not operate on a single known slug.

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?

Usage is implied through 'by slug' — the agent can infer this tool is for single-article lookups when a slug is available. However, it does not explicitly compare against siblings, state when not to use it, or mention alternatives for listing or searching, so the guidance remains implicit rather than explicit.

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