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

Annotations already declare destructiveHint=true, idempotentHint=true, openWorldHint=true, and readOnlyHint=false, so the safety profile is fully structured. The description adds genuine behavioral context by stating the outcome ('the contact stops receiving campaigns'), but says nothing about reversibility, permissions, or re-subscription.

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?

Front-loaded with a 'WRITE:' marker, then the effect, then the endpoint — three tight clauses with no filler. The endpoint line is mildly redundant but does anchor the operation.

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 single-parameter mutation whose annotations already cover the safety profile and which has no output schema, the description supplies purpose, impact, and endpoint. Only the return value and error/permission behavior are absent, which is acceptable at this complexity.

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 description coverage is 0% and the schema adds only numeric bounds, so the description must carry param meaning. It conveys that contact_id is a path identifier via the POST /contacts/{contactId}/unsubscribe template, but adds no format or sourcing detail beyond that.

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 email marketing') with the scope narrowed to a single contact, and even names the underlying endpoint. No sibling offers unsubscribing, so the agent can identify the intended action immediately.

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 is implied by the description ('unsubscribe one contact'), and it clarifies email-marketing scope, but it never states when to use this versus related tools like sendlane_remove_contact_from_list or when not to unsubscribe. No prerequisites or alternatives are given.

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