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

Goes well beyond the annotations by disclosing that this is a real write which re-verifies every participant's availability and refuses if anyone is busy (never double-books), that the caller is the organizer so no organizer handle is needed, and that Sync Pro/Lucie Membership plus live booking pages are required. This is exactly the extra behavioral context annotations cannot carry.

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?

Purpose and the key write semantics are front-loaded, and each sentence carries operational content (organizer identity, re-verification, prerequisite call, eligibility). It is on the long side for a single tool, with the eligibility sentence stacked at the end, but nothing is truly 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?

For a non-idempotent, open-world write tool with no output schema, the description covers preconditions, failure behavior, and eligibility. The main remaining gap is what the caller gets back (event link, confirmation, invite status) and any rate/limit constraints.

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 schema documents all five parameters; the description still adds meaning by clarifying that participantHandles covers only the *other* participants (the caller is the organizer) and that durationMinutes must be one the organizer offers. It adds some value but not syntax or format detail 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?

States a specific verb (Confirm), resource (group meeting across several Lucie hosts), and the concrete side effect (ONE shared Google Calendar event with everyone invited). The scope and the 'one shared event' behavior clearly separate it from book_meeting and create_group_event.

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 prerequisite workflow ('Always call find_group_times first and copy an exact common-slot start') and a pre-call checklist (time per zone, participants, title, reason), plus eligibility constraints (Sync Pro/Lucie Membership, live booking pages). It does not explicitly say when to prefer book_meeting or create_group_event instead, so the alternative routing is only partial.

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