indexnow_verify_key

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

Annotations already provide readOnlyHint=true, and the description adds useful non-obvious behavior: the key comes from configuration, is never passed in, and the tool verifies several specific HTTP/content conditions. It does not overstate behavior or contradict annotations.

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?

Three tightly packed sentences with no filler. The purpose is front-loaded, followed by usage guidance and a valuable parameter-related clarification.

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 two-parameter read-only diagnostic tool with an output schema, the description covers purpose, behavior, and usage context well. However, the semantics of host and key_location remain undocumented, which leaves ambiguity for an agent deciding whether to pass them.

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. The only useful clue is that the key is read from configuration, but the two parameters host and key_location are never explained, including whether they override the configured defaults or how they interact with each other.

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 ('Check') and resource ('this host's IndexNow key file'), plus concrete success criteria (reachable, HTTP 200, served as text, exactly configured key). This clearly differentiates it from the submission-oriented sibling indexnow_submit.

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?

Explicitly says to use this tool to diagnose a rejected submission and notes that submissions already run this check and abort on failure. It gives clear context but does not name an alternative tool or state when not to use it.

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