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

Annotations already establish readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context the annotations don't: the return is Markdown, and each story carries two addresses (Observatory site and source). Since there is no output schema, this return-format disclosure matters.

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?

One sentence, front-loaded with the resource and scope, and every clause (format, story addresses) carries information an agent needs. The phrasing 'each of its stories' addresses on the Observatory's site and at the source' is slightly heavy but not wasteful.

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 single-parameter read tool with annotations covering safety, the description supplies the one thing structured data lacks: the shape of the returned content. Error behavior for an invalid or nonexistent id is unaddressed, but nothing critical to invoking it correctly is missing.

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 coverage is 100% with a single well-documented id parameter, so baseline is 3. The description adds no syntax, format, or range detail beyond what the schema already provides.

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?

States a specific resource (one issue) and its scope ('in full'), plus the output format (Markdown). This clearly distinguishes it from latest_issues (a list) and search_news (a search), though it never explicitly says the verb 'retrieve by id'.

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?

No when-to-use guidance, no statement of prerequisites, and no naming of alternatives. The routing hint ('as latest_issues and search_news give it') lives in the parameter schema, not the description, so an agent gets no help choosing this tool over its siblings from the description alone.

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