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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the trailing 'Read-only; changes nothing' is largely redundant. What the description genuinely adds beyond the annotations is the shape of the behavior: it aggregates sender verification plus domain authentication and additionally reports gaps and the fix, which is the useful behavioral signal here.

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?

One front-loaded sentence carries the whole purpose, the enumerated outputs, and the remediation hint, followed by a three-word safety clause. Nothing is padding and nothing needed is deferred.

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?

With no output schema and no parameters, the description must explain what comes back — and it does: sender list with verification state, domains with auth status, missing items, and the tool that resolves each. That is sufficient for an agent to decide to call it and to act on the result.

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 tool takes zero parameters, so there is nothing for the description to disambiguate. It correctly avoids inventing options and makes clear the check is account-wide, consistent with additionalProperties=false and an empty schema.

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 and resource — checking account readiness to send campaigns — and enumerates exactly what is inspected: senders (verified or not) and sending domains with authentication status. It also distinguishes itself from the raw list siblings (list_senders, list_domains) by being a diagnostic that says what is missing and which tool fixes it.

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?

Usage context is clear: this is the pre-flight readiness check before sending campaigns, and the description tells the agent the output routes to a remediation tool. It does not explicitly say when to prefer list_senders or list_domains instead, so the sibling differentiation is implied rather than spelled out.

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