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

Annotations already declare destructiveHint=true, readOnlyHint=false, and idempotentHint=true, so the safety profile is covered. The description adds nothing beyond restating 'delete' — no mention of cascade effects on list membership, permanence, or the required preview/confirm two-step, all of which would be valuable for a destructive operation.

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?

A single front-loaded sentence with zero filler. It is efficient, though its brevity leaves behavioral gaps rather than being over-stuffed.

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 mutation, the annotations supply the safety flags and the schema supplies the confirm/dry_run protocol, so an agent can technically execute correctly. However, the description itself does not mention the two-step confirmation requirement that the annotation title hints at, leaving the description thin relative to the tool's risk.

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 100%, so all three parameters (list_id, confirm, dry_run) are fully documented with the preview-then-confirm pattern explained inline. The description's 'by ID' lightly reinforces the required key but adds no syntax or format detail beyond the schema; baseline 3 applies.

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 (delete), resource (contact list), and lookup key (ID), which distinguishes it from delete_contact, delete_tag, and delete_custom_field siblings. It stops short of explicitly differentiating behavior against those alternatives, but the resource is unambiguous.

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 description gives no indication of when to use this versus alternatives (e.g., delete_contact) or of prerequisites. The useful preview-then-confirm workflow guidance lives in the schema's `confirm` parameter description, not in the tool description itself.

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