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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds useful context: what mailers are, that 'status' returns delivery/open statistics, and which optional filters apply. It does not discuss pagination behavior for the list action, which is the main remaining gap.

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-loads what the tool reads, then the sibling exclusion, then a compact per-action breakdown. Bulleted action dispatch is easy to scan and no sentence is redundant.

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?

With a 100% covered schema, full annotations, and an output schema, the description supplies everything else an agent needs: resource meaning, action semantics, alternative tool, and provenance of event_id. Nothing required to invoke correctly is missing.

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 coverage is 100%, so parameters are already documented. The description still adds value by tying parameters to actions (kind_filter and feature_selection_id only for list, mailer_id only for get/status) and clarifying that event_id is an event UUID from search_events.

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 and resource ('Read mailers - the event's EMAIL campaigns') and enumerates the content types (registration confirmations, reminders, promotions, delivery stats). It explicitly disambiguates from the sibling read_notifications, so an agent can distinguish the two without inspecting schemas.

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?

Names the alternative tool for push/in-app announcements and the condition that selects it, then documents the three action modes and their prerequisites (mailer_id required for get/status). It also states that event_id must come from search_events, removing a common inference gap.

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