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

Annotations only provide destructiveHint=false. The description adds meaningful behavioral context beyond that: it discloses the batch cap (max 100) and, critically, that each removal emits the contact.list_removed event which may trigger automations. This side-effect warning is exactly the kind of context a caller needs before a bulk 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?

Two tight sentences, front-loaded with the action and scope, followed by the consequential side effect. No filler whatsoever.

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?

No output schema exists, so the description need not explain returns, and the event side-effect disclosure is a strong addition. However, it omits any note on required permissions or whether removal is idempotent, and leaves listId semantics unexplained.

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 must carry parameter meaning. It only partially addresses contactIds ('one or more contacts (max 100)') — and the 100 limit is already enforced by the schema's maxItems. The listId parameter is never explained, leaving half the parameters without added semantics.

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 ('Removes') and resource ('one or more contacts ... from a list'), so the operation is unambiguous. It implicitly distinguishes itself from the inverse sibling add_contacts_to_list, but does not name any alternative explicitly.

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?

There is no guidance on when to use this tool versus delete_contact or add_contacts_to_list. The note that removal can trigger automations is useful consequence context, but it is not selection guidance.

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