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

Annotations already declare destructiveHint=true, idempotentHint=true and openWorldHint=true, so the safety profile is covered. The description adds useful semantics the annotations don't carry — the concrete effect ('stops receiving that list's email') and the write verb — but says nothing about reversibility, whether a confirmation is needed, or what happens if the contact is not subscribed.

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 sentence, front-loaded with the 'WRITE:' classification and the effect in parentheses before the endpoint. Nothing wasted, though the trailing path fragment is somewhat redundant with the schema.

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?

A two-parameter write tool with full annotation coverage and full schema coverage needs little more, and the effect statement helps. Still, the absence of any note on unsubscribing being reversible (e.g. via a resubscribe path) or on the relationship to block_emails leaves a gap for an agent choosing between the two.

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% and both parameters are documented as numeric ids as returned by the list tools. The description's URL template only restates that list_id is a path segment and contact_id a query value, adding no meaning beyond the 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 ('unsubscribe one contact from one list') and even the side effect in parentheses, plus the HTTP route. It is clear what the tool does, though it never distinguishes itself from the sibling emailchef_block_emails, which is the natural source of confusion.

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 scope words 'one contact from one list' imply the per-list nature of the operation, but there is no explicit guidance on when to use this versus emailchef_block_emails or emailchef_update_contact, nor any prerequisite such as the contact needing an active subscription.

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