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

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds information annotations cannot convey: currency and time zone are permanent, and confirm=false produces a dry-run of the exact payload. It does not mention required auth/permissions or what a failure leaves behind, keeping it below a 5.

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 short paragraphs, purpose front-loaded, the permanence warning capitalized and placed where it will be read before the call. No filler sentences; each one either scopes the tool or prevents an irreversible mistake.

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?

An output schema exists, so return values need not be described. For a destructive, non-idempotent mutation the description covers the irreversible fields, the dry-run escape hatch, and auto-linking to the manager. Missing only permission/authorization prerequisites.

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?

With 0% schema description coverage, the description must carry the load. It explains manager_customer_id (the owning MCC), confirm (dry-run toggle), and the consequence of getting currency_code/time_zone wrong. Only name and tracking_url_template go unexplained, so it compensates well without being complete.

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 ('Creates a NEW Google Ads client account under a manager (MCC) account') plus the target audience (agencies onboarding a client). This is clearly distinguishable from siblings like connect_google_ads or create_search_campaign, which operate on existing accounts.

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 clear context for when to use it (onboarding a new client under an MCC) and routes the agent to list_accounts for the manager_customer_id, plus a confirm-before-creating instruction. It never explicitly states when NOT to use it or names the alternative for an existing account, so it falls short of the top score.

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