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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint, so the safety and idempotency profile is fully covered. The description adds the useful detail of which metrics are returned (views, revenue, subscribers), which matters because there is no output schema, but it says nothing about granularity, aggregation, or auth needs.

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?

A single front-loaded sentence with zero filler. It is efficient and readable, though its terseness is also the source of the missing usage and behavioral detail.

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 one-parameter read-only tool whose annotations carry the safety profile and which has no output schema, the description is largely sufficient; naming the returned metrics fills the main gap. Minor omissions (aggregation granularity, period semantics) remain but do not block correct invocation.

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?

There is a single parameter ('days') with 100% schema description coverage including default, min, and max. The description's 'for a time period' only loosely restates what the schema already documents, so the baseline 3 is appropriate.

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+resource ('Get analytics summary') and enumerates the returned metrics (views, revenue, subscribers) plus the scope (a time period). It is immediately distinguishable from the unrelated siblings, though it doesn't explicitly contrast with any alternative since none exists.

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 phrase 'for a time period' hints at the input scope but gives no when-to-use, when-not-to-use, or alternative-tool guidance. For a simple read tool this is tolerable, but the description provides no explicit usage direction.

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