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

With annotations covering only safety flags, the description supplies the behavior that matters: a draft card in the Stream by default, immediate publish gated on both an app permission ("May publish directly") and an under-18-visibility condition, plus the side effect that followers are notified once. That is well beyond annotation coverage, though error/rate-limit behavior is still unstated.

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?

It is reasonably short and the purpose clause leads, but the style is oblique — "reach is measured in who comes" and the em-dash clause about "its channel's event" cost parsing effort without adding usable information. The publish-gating sentence, by contrast, earns its length.

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 an 8-parameter mutation with nested objects, an output schema and 88% schema coverage, the description covers purpose, eligibility constraints, consent and default draft/publish behavior. The only gap is that it does not tell the agent when to prefer this over the household-event or post siblings.

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 88%, so the schema already explains as, mode, place, title, startsAt, endsAt and capacity in detail. The description mainly restates the mode default and the place restriction rather than adding format or interaction rules the schema lacks, so it sits at the baseline when the schema does the heavy lifting.

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 states a concrete verb and resource — create an event for a group/channel the person runs, covering sign-ups, waitlist and reminders — which is more specific than the title. It gestures at a sibling ("Like create_post") but only as an analogy for the draft workflow, not as a disambiguation from the closer sibling add_household_event, so an agent still has to infer which event tool applies.

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?

It gives one explicit consent rule ("Only when they ask") and hard eligibility limits (free events only, public place or venue, never a private home), which is real usage guidance. However it never names an alternative tool or an exclusion such as "use add_household_event for household-only events", so the routing between siblings remains inferred.

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