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

Annotations only declare readOnlyHint=false, destructiveHint=false and openWorldHint=true. The description adds genuinely non-obvious behavior: the result is a DRAFT that the founder must publish, images are not handled here, and the event has hard lifecycle limits (31 days max duration, card visible from up to 14 days before). It omits auth/scope requirements and what is returned, but adds real value beyond the annotations.

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?

One dense paragraph that front-loads the resource definition and constraints, which is good. However it opens with a bare noun phrase rather than an action, and the trailing tokens 'Growth. Free.' are unexplained noise that doesn't help an agent decide or invoke.

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 11 parameters, 8 required, no output schema and low schema coverage, the description should carry more weight. It covers the concept, lifecycle constraints and text limits well, but leaves the agent guessing on enum choice (badge, purpose), date formats, and what a successful call returns.

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 only 36%, so the description must compensate. It partially does: it gives the per-locale text limits (30/50/120) and, more importantly, explains the timing relationship between publishStart (up to 14 days before) and event duration (max 31 days). But it says nothing about the badge and purpose enums, the optional appId, referenceName, or the expected format of eventStart/eventEnd, leaving half the parameters undocumented anywhere.

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?

The description names the concrete resource ('an in-app event as a draft in App Store Connect') and explains what such an event is (a card in search results and on the product page for something time-bound). Combined with the title 'Draft an in-app event' and the name app_event_create, the create-draft intent is unambiguous, though the description itself never uses a verb and doesn't distinguish it from siblings like app_events or app_experiment_create.

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?

'Its card and page images are added by the founder in App Store Connect, who then submits it' implicitly bounds the tool's scope: it creates the draft only, and image upload plus submission happen elsewhere. That is useful context, but there is no explicit when-to-use statement, no named alternative, and no prerequisites or exclusions.

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