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

Annotations already declare the read-only/idempotent safety profile, and the description adds genuinely new context: the returned fields (property/account names, stream hostnames, traffic evidence, saved selection), pagination via nextOffset, and the interpretation caveat that empty recent traffic does not prove tracking is missing. This is rich behavioral disclosure beyond structured fields.

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?

Purpose and pagination guidance are front-loaded, and every sentence carries actionable content (candidates, caveats, next tool). It is dense and packed into a single block, but there is little waste.

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 an output schema present and annotations covering safety, the description still supplies the workflow (paginate, present candidates, then select), the prerequisite source of siteId, and the key interpretation caveats. Nothing needed to call it correctly is 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 coverage is 100%, so limit/offset/siteId are already documented; the schema's offset field even repeats the 'use nextOffset to continue discovery' guidance found in the description. The description adds no syntax or format detail beyond what the schema provides, so the baseline of 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 and resource ('Find Google Analytics properties for the selected site using connected accounts'), and its scope is clearly distinct from siblings like list_sites and select_ga4_property. An agent can identify exactly what this returns without opening the schema.

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?

Explicitly names the follow-up path ('ask the user to choose before calling select_ga4_property') and gives a negative rule ('do not claim absence from an incomplete scan'). Alternatives and conditions are spelled out rather than left to inference.

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