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

Annotations already cover the safety profile (not read-only, not destructive, not idempotent), so the bar is lower. The description adds genuinely operational context: the execution loop for >10 attendees, which the agent must implement itself. It doesn't warn that non-idempotent retries of a partially completed batch will duplicate attendees, nor what happens on per-attendee validation failure.

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 sentences, front-loaded with the action, then the batching procedure, then dependency routing. Slight redundancy: the >10 instruction appears here and again in the attendees parameter description, and the 'Provided event' phrasing adds nothing.

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 2 parameters, full schema coverage, and an output schema covering returns, the description is nearly sufficient. What's missing for a bulk mutation is failure semantics — partial success, duplicate detection, and whether the caller should stop the loop on error.

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 the baseline is 3. The description's 'batches of 10' restates the schema's maxItems constraint, and its id-lookup hints largely duplicate schema text ('Use read_interests action \'list\' to get valid ids'). It adds little semantic meaning beyond the schema.

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?

Opens with a specific verb+resource+scope: 'Create attendees in batches of 10 in the provided event.' The batching constraint and event scoping distinguish it immediately from update_attendee, delete_attendee, and add_attendees_to_groups.

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 concrete prerequisite routing — read_attendees for inspection, read_groups for group ids, read_interests/read_services action 'list' for valid ids — so an agent knows what to call first. It stops short of stating when not to use this tool (e.g., adding existing attendees to groups, or updating already-created attendees).

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