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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, and the description reinforces this with the non-obvious guarantee that 'The token is deterministic for the host, so calling this again returns the same value' and 'Nothing is stored.' That determinism/no-persistence detail is real value beyond the annotations, though it says nothing about failure modes or auth requirements.

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 first frames the step, the second lists the concrete output artifacts, the third handles the idempotency question. Front-loaded and every sentence earns its place.

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?

There is no output schema, so the description carries the return-value burden and does it well — it names what comes back (the token) and the three supported publishing channels. Combined with the schema and annotations, an agent has everything needed to call this 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 coverage is 100%, so the baseline is 3, but the description adds meaning by clarifying that the token is derived from 'the URL's host' — implying path/query portions of the URL are irrelevant. That is a genuine semantic addition beyond the schema's 'Public https URL' wording.

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 states a specific verb and resource ('Returns the domain-ownership token for the URL's host') and positions itself as 'Step 1 of a readiness scan', so its role in the workflow is clear. It stops short of explicitly contrasting itself with readiness_get_scan or readiness_request_scan, which would have earned a 5.

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?

'Step 1 of a readiness scan' tells the agent this is the entry point that must precede the scan, giving clear sequencing context. However, it never states when to skip this tool (e.g. if a token was already published) or names the sibling it leads into, so there are no explicit exclusions.

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