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

Goes well beyond annotations: discloses the auth requirement (account token), the cancellation timing (keeps working until month end, stops renewing), the dry-run behavior of confirm, and that no charge occurs. This adds real operational context on top of destructiveHint/idempotentHint.

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?

Five short sentences, front-loaded with the auth prerequisite and core action, then billing timing, then confirm semantics. Every sentence carries information; nothing is redundant.

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 destructive two-parameter mutation with no output schema, the description covers the key behaviors an agent needs (auth, timing, no charge, apply switch). The only gap is not naming where re-enablement happens, which would round out the lifecycle picture.

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 both parameters are already documented in the schema. The description reinforces confirm=true as an apply switch and clarifies the billing consequence, but adds little syntax or format meaning beyond what the schema provides.

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 (turns off) and resource (email for a site's domain), with scope made explicit. It is clearly distinguishable from siblings like email_status, remove_email_address, and rename_main_inbox, which handle different email operations.

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?

Gives clear context: cancellation takes effect at end of the paid month, confirm=true applies the change, and turning it back on is not handled here. It lacks the explicit name of the sibling tool that re-enables email, so routing is implied rather than stated.

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