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

Annotations already declare destructiveHint=true and readOnlyHint=false, but the description goes well beyond that: it spells out irreversibility ("this cannot be undone"), the concrete effects (numbers fall to zero, people disappear from the funnel, already-sent emails are not recalled), and the blast radius (acts on the connected WordPress site, nothing else touched). That is exactly the extra context an agent needs before a mass delete.

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 the destructive action and scope, then preconditions, then effects, then alternatives — a sound ordering. It is slightly padded by the quoted example utterance and the trailing host-synonym list, which add recall value but not new operational meaning.

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, open-world tool with rich annotations and an output schema, nothing an agent needs is missing: what it destroys, what it does not touch, prerequisites, and safer alternatives are all stated. Return-value behavior is covered by the output schema, so the description need not repeat it.

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 the parameters are already self-documenting and the baseline is 3. The description maps loosely onto them ("needs the session, the webinar and a clear yes from you" for session_id, webinar_id, confirm), but adds no format or sourcing detail beyond what the schema already says.

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 concrete verb and a precise scope: "Deletes every registrant of one webinar in a single step." It also draws the contrast with the single-record sibling ("For one person there is a separate tool"), so an agent can choose between wi_delete_all_registrants and wi_delete_registrant without opening either schema.

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?

Gives an explicit when-to-use condition ("Take it only when a list should really go, for example after a test run on a fresh campaign"), preconditions (session, webinar, and a clear yes from the host), and two alternatives — the per-person delete tool and exporting the list as a file beforehand. It even prescribes reading the count first before invoking.

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