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

With no annotations, the description carries the full burden and does add real behavioral context: no cookies, visitors counted per day (a deduplication/counting semantic), and tier-based lookback limits (today on Free, 90 days on Pro). It still omits auth/permission requirements and rate or freshness behavior, so it is strong but not complete.

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?

Three dense sentences, front-loaded with the returned metrics and followed by counting semantics and tier limits. Every sentence earns its place with no filler or repetition.

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?

No output schema exists, but the description compensates by naming the return dimensions (per-day visitors/page views, top pages, referrers, device split). For a low-complexity read-only tool with 3 well-documented params, this is nearly complete, with only auth/permission context missing.

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 schema already documents env, days, and project, establishing a baseline of 3. The description adds only marginal meaning, contextualizing the days parameter via the Free/Pro lookback window ('per day', 'up to 90 days') without adding format or syntax detail beyond the schema.

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 enumerates exactly what is returned (visitors and page views per day, top pages, referrer sources, phone vs desktop), which lets an agent distinguish this from metrics.get, logs.query, and requests.query. It is a clear retrieval of web analytics, though it never states the verb explicitly and relies on the name for the 'get' framing.

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 tier constraints ('Free shows today; Pro up to 90 days') imply the scope available to the caller, but there is no explicit when-to-use guidance and no mention of which sibling to prefer for adjacent needs (e.g., metrics.get or requests.query). Usage is implied rather than stated.

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