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

The annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description still adds value beyond them by signalling that this returns the FULL article (as opposed to the partial records from docs_search/docs_list) and that article_id is stable and unique while titles are not. It does not discuss failure behavior, which keeps it from a 5.

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, front-loaded with the operation and scope, followed by the precondition for the single parameter. No filler, no restatement of the tool name or annotations.

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?

This is a one-parameter, idempotent read tool with an output schema, so return values need no explanation here. The description covers what it does, what input it needs, and where that input comes from — nothing an agent needs in order to call 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 description coverage is 0%, so the description must carry the meaning of article_id, and it does: it identifies the field as a stable identifier obtainable from docs_search or docs_list and explicitly rules out titles as a substitute. That is meaningful semantics a bare string parameter would not convey; only the exact format/syntax of the ID is left unstated.

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 uses a specific verb+resource pair ("Fetch one full ... Docs article") plus a precise selector ("by its stable article_id"), which cleanly separates it from docs_search (discovery) and docs_list (enumeration). An agent knows exactly what it gets back in kind: a single complete article.

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?

It explicitly routes the agent to docs_search or docs_list as the source of a valid ID and warns that titles are not unique, which is real when-to-use guidance. It stops short of a full exclusion list (e.g., no statement about what to do if the ID is stale or the article is missing), so it is clear context rather than complete conditional routing.

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