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

Annotations declare readOnlyHint=true and openWorldHint=false, so the agent knows this is a safe read operation. The description adds the constraint that the slug must come from list_news, which reinforces the openWorldHint=false (closed world) by suggesting the slug is a known value. However, it does not describe the response format (e.g., whether it returns just text or metadata), but with annotations covering safety, a 3 is appropriate.

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 one concise sentence that front-loads the primary function ('full text') and specifies the input source. Every word earns its place, with no fluff or repetition.

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 tool with a single parameter and no output schema, the description is complete. It tells the agent what to provide (slug from list_news) and what to expect (full text). The lack of output schema is acceptable given the tool's simplicity. Minor gap: it doesn't mention whether the article includes metadata (e.g., author, date), but this is not critical for a READ operation.

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%: the schema already describes the 'slug' parameter as 'Article slug from list_news'. The description repeats this by stating 'by its slug from list_news' without adding new details. Since the schema carries the parameter semantics fully, the baseline of 3 is correct.

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 clear purpose: retrieving the full text of a single news article by slug. It identifies the resource (BinaSmart news article) and the input (slug). However, it does not explicitly distinguish it from the sibling tool list_news, though the relationship is implied by referencing list_news.

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 implies usage: use this tool after obtaining a slug from list_news. It provides clear context by referencing list_news as the source of the slug, but it does not explicitly state when NOT to use this tool or mention alternatives beyond the implied list_news. This is sufficient for most agents.

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