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

Annotations already declare destructiveHint=true and readOnlyHint=false, but the description adds real value beyond them: it discloses the side effect that contacts are moved to the setup default list (not deleted), and that confirm must be true. It stops short of stating irreversibility or permission requirements, but the contact-migration disclosure is exactly the kind of context annotations cannot carry.

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, each earning its place: what is deleted, what happens to contacts, and the required flag. The destructive side effect is front-loaded where the agent will see it first.

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 two-parameter destructive tool with no output schema, the description covers the essential context: scope constraint, side effect on contacts, and the confirmation precondition. Missing only minor details such as irreversibility or error behavior when the target is a default list.

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%, so the description carries the burden. It clarifies the semantics of the confirm boolean ('Requires confirm: true'), which is genuinely useful, but says nothing about listId beyond its name, leaving half the parameters undocumented in both schema and description.

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) and resource (a non-default list from the active setup), with a scope qualifier that pins down exactly what can be targeted. An agent can immediately tell this apart from create_list/update_list and understands the default list is off-limits.

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 'non-default' qualifier implicitly excludes default lists and 'Requires confirm: true' states a call precondition, but there is no explicit when-to-use guidance or named alternative (e.g., bulk_delete_contacts, update_list). Usage 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.