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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety and source profile is covered. The description adds that the response contains full text and a link, which is useful since there is no output schema, but it omits error behavior for unknown slugs and whether the full text is truncated.

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 sentence with no waste: identity, selector, provenance of the selector, and return contents are all front-loaded.

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 one-parameter read tool whose annotations already cover safety, the description covers what it returns and where the parameter comes from. Only not-found handling and details of the returned payload remain unspecified.

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 0%, so the description carries the burden for the single slug parameter. It usefully tells the agent the slug originates from list_articles or search, but does not describe the slug format or matching rules (case sensitivity, alternative identifiers like IDs or URLs).

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 verb (fetch) and resource (one Bayan article) with the key selector (slug), and explicitly says it returns full text and link. It implicitly contrasts with the plural sibling list_articles, though it never names get_hadith/get_verse/search as the other single-item routes.

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?

'from list_articles or search' tells the agent how to obtain a slug, which is exactly the precondition for calling this tool. It gives clear usage context but no explicit when-not-to-use statement (e.g., use list_articles to enumerate, use search for keyword lookup).

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