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

With no annotations provided, the description carries the full burden of disclosing behavior. It does not state whether the operation is read-only, if any permissions are needed, what the response format looks like, or any rate limiting. The terse description adds minimal behavioral context beyond the fact that statistics are computed.

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?

The description is a single, front-loaded fragment with no filler words. It is concise but perhaps overly terse; the inclusion of the classification dimensions makes it informative enough for a one-liner.

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?

The tool has no annotation, no output schema, and no parameters, so the description must explain what the returned statistics look like. Saying 'by type, source, status' implies dimensions but does not specify whether output is a count, percentage, time series, or other summary. A more complete description would clarify the return structure.

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 input schema has zero parameters, and the description correctly adds no parameter details since none exist. Per the rubric, a zero-parameter tool earns a baseline of 4; nothing is missing.

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 phrase 'Event statistics: by type, source, status' clearly identifies the tool as providing aggregated event statistics broken down by relevant dimensions. Although it lacks an explicit action verb, the intent is unambiguous and it distinguishes itself from the sibling tool event_log by implying aggregated data rather than raw logs.

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?

No guidance is given on when to use this tool versus alternatives such as event_log. The description only lists aggregation dimensions but does not state whether to use it for overviews, trend analysis, or specific operational purposes.

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