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

With annotations covering only the safety profile (readOnly=false, idempotent=false, destructive=false, openWorld=false), the description adds substantial context: dedup rule (by account, else email), that it never records consent, requires a connected account, requires hosting every event, dry_run counts without writing, list_id pins a stable id for campaign drafting, and what the result reports.

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 core action and dedup semantics before turning to optional filters and result shape. Dense em-dash structure packs a lot in efficiently, though the single long paragraph is heavier than ideal for scanning.

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, yet the description explains the return content (people, per-event counts, emailed count, marketing-eligible count, applied rule and matched counts), so return values are covered. Combined with auth and hosting prerequisites, the remaining gap is only the undocumented include_cancelled parameter.

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?

With 0% schema description coverage, the description carries the full burden and does so well: it explains event_ids source, list_name find-or-create, min_tickets ('2 or more'), min_events_attended, checked_in_only, min_net_spend_cents + currency (USD default), and list_id's purpose. It omits include_cancelled, leaving one parameter 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+resource ('Build ONE deduplicated list of everyone who RSVPed to / held a ticket for several of your events') with explicit scope and a concrete example. An agent can distinguish it from save_people_as_list or import_contacts_to_list because the source events are named.

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 clear context for use (aggregating the same people across multiple events, e.g. a dinner series), points to list_events for sourcing event_ids, and explains dry_run and list_name find-or-create behavior. It never names an alternative tool or an explicit when-not-to-use condition, so it stops short of a 5.

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