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

Annotations only declare destructiveHint=true; the description adds genuinely new behavior by disclosing PATCH-style semantics (omitted fields are untouched) and the start/end-plus-timezone coupling. It omits other behavioral context an agent would value, such as permission/scope needs, whether changes to a live event with sales are restricted, or what the call returns.

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 short clauses, tightly front-loaded with the update semantics and the key constraint before the low-value API path. The trailing 'Eventbrite: POST /events/{event_id}/' is mostly an implementation detail that does little for tool selection, but it costs only a few tokens.

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 20-parameter, destructive-capable update tool with no output schema, the description covers the update semantics well and the schema covers field-level detail. It is still silent on return behavior, on the destructive consequences of editing a published event, and on which edits belong to sibling tools.

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% and each of the 20 parameters is documented in the schema, so the baseline is 3. The description goes beyond that by explaining that all fields are optional and that supplying start_utc/end_utc obliges a timezone, adding meaning the schema does not state on its own.

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 ('Change fields of an existing event'), and the word 'existing' implicitly separates it from eventbrite_create_event and eventbrite_copy_event. It stops short of naming any sibling explicitly, so it does not reach the 5 bar of active sibling differentiation.

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 operating context: this is a partial update ('only the fields you pass are sent') and a cross-field prerequisite ('Changing start/end needs timezone too'). It never says when a different tool is required, e.g. routing ticket-class edits to eventbrite_update_ticket_class or visibility toggles to eventbrite_publish_event/eventbrite_unpublish_event.

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