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

Annotations already flag destructiveHint=true and idempotentHint=false, so the safety profile is known. The description adds genuinely useful context beyond that: the functional blast radius (support and marketing email halt) and what is NOT destroyed (domains and settings persist, and how to restore service). No mention of permissions or confirmation requirements, so not a 5.

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 short sentences with the action stated first, consequences second, and persistence caveat last. Every sentence carries distinct information with no filler or repetition of the title.

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 zero-parameter destructive toggle with no output schema, the description supplies everything needed: what is affected, what persists, and how the state is reversed. Nothing required to invoke it correctly is absent.

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. Baseline of 4 applies; no parameter-level meaning is needed or missing.

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?

Specific verb+resource ('Disconnect the workspace's Resend account') with an immediately clarified scope. The line 'Domains and settings are kept' distinguishes it from sibling domain-level tools like remove_mail_domain or list_resend_domains, so an agent can differentiate without opening schemas.

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 effect ('Support and marketing email stop') implies when an agent should reach for this tool, and the restoration path ('connects a key again in Settings → Email') implies reversibility. However, it never explicitly states when this is preferable to alternatives (e.g. per-domain removal, updating sender identity) or any preconditions.

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