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

With no annotations, the description carries the full burden. It states the tool is read-only, paginated, and describes filtering capabilities, including the exclusion of test-flagged events unless include_test=true. It also mentions the return value ('events + next_cursor'). This covers most key behaviors, though it omits rate limits or permission requirements.

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 two sentences: the first states the main purpose, the second details filters and return value. It is concise, front-loaded, and every sentence adds value.

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?

Given the complexity of 10 parameters and presence of an output schema, the description covers read behavior, pagination, filtering options, and the special case for test events. It is fairly complete, though it could specify the ISO date format more precisely or mention related usage concepts.

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 has 0% description coverage, so the description must compensate. It lists all major filters (meter, provider, consumer_class with values, channel, outcome with values, since/until as ISO date range) and implies pagination parameters. This adds significant meaning beyond the schema's minimal type/default information.

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 starts with 'Read usage events (paginated, read-only)', clearly specifying the verb 'Read', the resource 'usage events', and key traits. It distinguishes from sibling tools like list_meters and record_usage.

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?

The description lists available filters but does not provide explicit guidance on when to use this tool versus alternatives, nor does it mention when not to use it. It implies usage context through the filter options but lacks explicit exclusions.

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