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

Annotations are all false and provide no meaningful safety or idempotency context, so the description carries the burden. It discloses key side effects: created assets are 'shared in the account library,' it supports batched execution, and it clarifies that sitelinks are not display paths. It does not mention output/return values or idempotency, but covers the main behavioral traits well.

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?

The description is well-structured, front-loaded with the core purpose, and every sentence adds value. It efficiently packs scope, asset semantics, validation constraints, display-path clarification, and bulk support into a compact but readable format.

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 mutation tool with no output schema and no positive annotation support, the description is unusually complete: it covers purpose, scoping, asset structure, constraints, account-library sharing, and bulk execution. It stops short of explaining partial_failure semantics and expected response/error behavior, but overall it is strong for the tool's complexity.

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 0%, so the description must compensate. It does explain scope enum values, sitelinks fields (link_text, final_url, description1/description2), validation limits, and bulk arrays (target_ids, customer_ids). However, parameters such as account, target_id, customer_id, and partial_failure are left unexplained, leaving gaps for a tool with 8 parameters.

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 opens with a specific verb and resource: 'Create sitelink extensions and attach them to a campaign (default), the whole account (scope=customer) or an ad group.' It clearly defines the tool's scope options and distinguishes it from related concepts such as the ad's display path, and from sibling tools like google_ads_sitelinks and google_ads_sitelink_remove.

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 description provides clear context for when to use the tool, including scope selection ('campaign (default)', 'scope=customer', 'ad group') and important practical guidance such as 'Google needs at least ~2 sitelinks to actually show them.' It does not explicitly list alternatives or exclusions, but the sibling names and the create-specific verbs make the usage boundary inferable.

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