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

Annotations already declare this a safe, read-only, closed-world operation, so the description's job is to add context — which it does by disclosing the return contents (names, counts, first/last seen timestamps). It stops short of saying whether the list is complete, sorted, or paginated, but for a zero-parameter read that is a minor omission.

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 sentence, front-loaded with the resource and immediately followed by the payload shape. Nothing is redundant and nothing needs to be re-read.

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 no output schema and no parameters, the description carries the burden of describing the result, and it does so reasonably by naming the three fields returned. It could add ordering or size expectations, but the core information an agent needs to decide to call it is present.

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?

The tool takes no parameters, so there is nothing for the description to disambiguate, and the 4 baseline applies. The schema is an empty object with 100% coverage, consistent with the description's framing as an unfiltered enumeration.

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 resource precisely ('every event name the app has sent') and even characterizes the payload (counts, first/last seen). It does not, however, contrast itself with the sibling 'query_events' or 'get_top_features', so an agent must infer the boundary between enumerating names and querying event data.

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?

There is no explicit when-to-use statement and no named alternative. The only guidance is implicit in 'every event name', which suggests a discovery/listing use case when an agent needs valid event names before calling query_events, but that routing is left entirely to inference.

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