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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe read-only nature is covered. The description adds that the profile is public and includes recent articles, but does not disclose auth requirements, rate limits, or error behavior beyond what the annotations already imply.

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 tightly written sentences. The purpose and returned fields are front-loaded, and the input instruction follows immediately, with no filler.

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 one-parameter read tool with an output schema and read-only/open-world annotations, the description is nearly complete: it states what is fetched, what is returned, and where to obtain the input URL. A mention of acceptable URL formats would make it fully self-contained.

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 parameter meaning. It does so by specifying that the required URL should be a canonical author page URL from a story byline, which is more informative than the bare string type in the schema, though it does not detail URL format.

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 ('Fetch') and resource ('9to5Google author's public profile'), and lists the profile contents. This clearly distinguishes it from sibling article, news, and headlines tools for the same site.

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 provides an input prerequisite ('Provide a canonical author page URL from a story byline'), which implies use when an author page URL is available. However, it never states when to choose this tool over alternatives such as ninetofivegoogle_article or ninetofivegoogle_news.

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