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

The readOnlyHint annotation already covers safety, so the description adds useful behavioral context: the endpoint path, the aggregation nature, and the grouping/dimension behavior. It does not mention any side effects or rate limits, but for a read-only analytics query this is acceptable.

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 short and front-loaded with the core purpose. The 'Read-only.' sentence repeats the annotation, which is slightly redundant, but the endpoint suffix adds useful specificity without bloat.

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 a moderately complex read-only analytics tool with full schema coverage, the description is complete enough: it states the resource, grouping, date range, and endpoint. The absence of an output schema is mitigated by the clear 'plays' analytics scope, though a brief note on response format would have been ideal.

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 100%, so the baseline is 3. The description reinforces the meaning of date range and dimension, but does not add anything beyond what the schema already documents for each parameter.

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 uses a specific verb-resource pairing: 'aggregated play analytics for live streams' with explicit grouping by dimension and date range. This clearly distinguishes it from sibling tools like apivideo_get_video_analytics, which targets on-demand video analytics.

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 gives clear context for use: it is for live stream play analytics over a date range, grouped by a dimension. It does not explicitly name alternatives or exclusion criteria, but the scope is unambiguous enough for an agent to select it appropriately among siblings.

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