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

Annotations flag this as destructive and open-world, and the description meaningfully enriches that by explaining the preview-first, confirm-gated execution model — the single most important behavioral fact for an agent here. It does not cover what happens if a link already exists, whether the link is reversible, or what permissions are required, so it is strong but not exhaustive.

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, no filler. The effect of the tool is stated first, then the safety-critical call sequence, which is exactly the order an agent needs it in.

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 destructive, open-world mutation with five parameters and no output schema, the description supplies the essentials: what is created, the preview/confirm protocol, and the ID format. Residual gaps — behavior on an existing link, permission requirements, and the meaning of the folder/language card parameters — are minor but real.

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 60%, and the description compensates for the two most consequential gaps: it specifies the customer_id format (no hyphens) and defines the semantics of confirm as the trigger that actually creates the link rather than a mere acknowledgement. The folder, language, and property parameters are left entirely to 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?

States a specific verb and both resources (GA4 property → Google Ads account) plus the business reason (sharing conversions and audiences). The customer-ID format hint and the 'selected property' framing let an agent distinguish this from neighbors like google_ads_link_merchant_center or the read-only ga4_* reporting tools.

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?

Gives an explicit two-step invocation rule: first call is a preview, and the mutation only happens on a repeat call with confirm=true after the user agrees in chat. That is unusually actionable when-to-use guidance. It stops short of naming an alternative or stating when not to link at all, which keeps it from a 5.

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