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

Annotations already declare readOnly, idempotent and non-destructive, so the safety bar is lower. The description still adds genuinely useful behavior: one row per calendar day, null where data is missing, and the start-day rule for young publications, which the agent cannot infer from the schema.

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?

Front-loads the key fields ('Day by day: total and paid subscribers, followers and views'), which is good. The subsequent sentence is clunky and overloaded ('as the charts on the dashboard home and in Audience') and could be tightened without losing information.

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 a single optional parameter and no output schema, the description does the necessary work of describing the return shape: one row per day, the fields returned, and null semantics. It is largely complete for a simple read tool, with only the row/site-vs-app granularity left slightly ambiguous.

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 coverage is 100% with a single enum parameter and a documented default, so the schema carries the parameter semantics. The description adds no format or semantics for 'period' beyond what the schema already says, so baseline 3 applies.

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?

States a specific verb-driven purpose: per-day total and paid subscribers, followers, and views, one row per day. It is clearly a daily time-series stats tool distinguishable from sibling stats tools, though it never names those siblings explicitly.

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?

Usage is implied by 'Day by day' and the reference to dashboard charts, giving an agent a sense of when this applies versus a snapshot tool. However, it never states when to prefer get_publication_stats, get_audience_insights, or get_post_stats, so routing is left to inference.

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