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

With no annotations provided, the description carries the full burden and does well: it discloses that URLs are validated, that specific rules are enforced (same-host, 10000 limit, https/http consistency, fragment stripping, de-duplication), and that it returns reasons for dropped URLs. It does not explicitly mention error behavior for invalid keys, but 'validates' implies this, making the transparency strong.

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 two sentences, each dense with distinct information: the first covers purpose and outputs, the second lists enforcement rules. There is no fluff or redundancy, and it is front-loaded with the tool's core function.

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?

Given the tool has 5 parameters, no output schema, and moderate complexity, the description is quite complete: it explains what is returned (body, endpoint, curl, dropped URL reasons) and the validation rules applied. It could clarify what happens on invalid key or non-URL inputs, but overall it provides enough context for an agent to select and use the tool effectively.

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?

The schema already covers all parameters with descriptions (100% coverage), so baseline is 3. The description adds meaning by introducing constraints not present in the schema: the 10000-URL batch limit, https/http consistency, fragment stripping, and de-duplication, which notably apply to the urlList parameter. This enriches the agent's understanding of parameter validation expectations.

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 clearly states the tool's purpose with a specific verb ('validates' and 'returns'), the resource (IndexNow POST body), and the concrete outputs (JSON body, endpoint, curl command, dropped URL reasons). It distinguishes itself from the sibling validate_indexnow_key tool by focusing on building a payload and validating both key and URL list, not just the key.

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 usage is implied by the tool's name and description (build a payload, validate key/URLs), but there is no explicit mention of when to use this tool over validate_indexnow_key or diff_sitemaps. No alternatives are named or excluded, so the agent receives no direct comparative guidance.

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