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

With no annotations, the description carries the full burden, and it does disclose two real behavioral facts: submission is gated on successful verification, and the batch is capped at 100 URLs to an external endpoint. It omits what a failed verification returns, whether the key parameter is mandatory for submission (the schema requires only host), and whether the call is idempotent or rate-limited.

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 tight sentences with the verify-then-submit behavior front-loaded and the mode switch second. No filler, no redundant restatement of the tool name.

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 mutation tool that hits an external API with no annotations and no output schema, the definition covers the core contract but leaves the failure path and the key parameter's role unspecified. An agent could invoke it but would not know how to interpret an unsuccessful verification.

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 50% — host and urls are documented inline, while key and action are bare. The description recovers the action semantics (default verify vs. submit), but says nothing about the key: whether it is required, where it comes from, or how it relates to the key file being verified.

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 names the concrete verb and resource — verifies an IndexNow key file on a domain and submits URLs to api.indexnow.org — plus the 100-URL ceiling. That is far more specific than a name restatement, though it never notes that this is the only write/submission tool among a set of read-only SEO checkers.

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 explicitly gives the switch that changes behavior: 'Set action to "submit" to send URLs; the default only verifies,' which tells an agent exactly which mode to pick. It stops short of saying when to reach for this tool versus sibling diagnostics, and gives no prerequisites (e.g. that the key file must already be hosted).

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