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

Annotations already declare readOnlyHint=true, idempotentHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: the response is markdown and terminates in a canonical URL. It does not mention error behavior for an unknown slug or whether lang changes the rendered content.

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?

A single dense sentence with the key fact – this is one document – front-loaded, and no filler. It is a fragment without an explicit verb, which slightly weakens readability but wastes no space.

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?

With a rich annotation set, full schema coverage and an output schema, the description only needs to frame selection and format. It covers format (markdown, canonical URL) but omits routing guidance against five document-related siblings, leaving a real gap for an agent choosing among them.

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%, with slug documented as 'the last part of its /documents/ URL' and lang as an en/dv enum, so the schema carries the parameter burden. The description adds nothing further about either parameter, which is the baseline expectation when coverage is complete.

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 names the resource precisely ('One primary-source document') and enumerates its contents (issuer, reference, dates, GMM summary, file link, news coverage), which separates it from get_article and get_page_markdown. The verb is implicit – it never says 'retrieve/fetch by slug' – but the scope is unambiguous.

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?

There is no statement of when to call this versus list_documents, search_documents, or the sibling get_article. The agent must infer from the name and the word 'primary-source' that this is a slug-keyed single-record fetch.

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