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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the description's job is data semantics — and it delivers: counts are daily visitor estimates, a person may be counted again across midnight, and these are not persistent people or lifetime uniques. That is exactly the kind of caveat that prevents misreading a report.

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?

Two sentences, zero filler. The scope-and-purpose sentence comes first, the important data caveat second — properly front-loaded.

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 read-only report tool with no output schema and modest parameter complexity, the description covers what is returned at a high level (counts, history, breakdowns) plus the interpretive caveat. The missing piece is any hint of response shape or granularity for history/breakdowns, but annotations carry the rest.

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 67%: app and environment are documented in the schema, while range is only an enum with no prose explanation. The description adds no parameter-level detail beyond restating 'one application and environment', so it neither compensates for the range gap nor adds meaning beyond the schema. Baseline 3.

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 ('Read') and a specific resource ('Cookieless visitors counts, history and breakdowns') scoped to one application and environment. That distinguishes it from generic siblings like get_analytics_overview or get_breakdown, 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?

The word 'separate' implies this is a distinct cookieless data source rather than the general analytics endpoints, which is a useful usage hint. But there is no explicit when-to-use/when-not, no mention of get_cookieless_status or get_cookieless_install_instructions as adjacent tools, so selection 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.