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

Annotations already declare readOnlyHint=true and openWorldHint=true, and the description adds substantial context: the readiness check, what ready=false means, concrete next steps for creating the key file, and the fact that the key is public and fixed per workspace/domain. It does not contradict the read-only annotation.

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 definition is front-loaded with purpose and prerequisite, and most sentences carry useful information. It is dense and slightly verbose in the IndexNow explanation, but no major part is wasted.

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?

Although an output schema exists, the description still explains the meaningful return fields and the ready=false follow-up. Combined with the parameter and alternative guidance, it gives an agent everything needed to invoke and interpret this tool correctly.

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 compensate, and it does: url is defined as a domain or URL with a default to the workspace website, and workspace is defined as a customer workspace slug that is optional when only one workspace exists.

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 first sentence states a specific resource (IndexNow key of the website) and a specific check (whether the key file is already online). It also explicitly frames the tool as a prerequisite for site_indexnow_submit, distinguishing it from the submit sibling.

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 says the key is a prerequisite for site_indexnow_submit and explicitly notes that Google does not participate in IndexNow, routing that case to sc_submit_sitemap. This gives clear when-to-use and alternative guidance.

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