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

Annotations already declare non-read-only, non-destructive, non-idempotent behavior, so the bar is lower; the description still adds the non-obvious behavioral fact that the asset is inert until linked, which annotations cannot convey. It does not discuss duplicate creation or asset-name reuse, which would matter given idempotentHint=false, but the linking dependency is the key disclosure.

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 core purpose and the linking caveat are front-loaded, and the parameter constraints are scannable. The Args:/Returns: docstring formatting and the Returns line duplicate the output schema and required-parameter list, adding modest redundancy without obscuring the content.

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 three-parameter mutation tool with an output schema already covering the return value, the description supplies everything an agent needs: the resource concept, the required follow-up linking call, all valid header values, and the customer_id format. Nothing material is left unstated.

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% and no parameter has enum constraints, yet the description documents all three parameters: customer_id format ('numbers only, no hyphens'), the full allowed header vocabulary (13 valid values that the schema does not enforce), and the values list with a minimum-size recommendation. This compensates fully for the empty schema and prevents the most likely invocation errors.

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 ('Creates a structured snippet asset') and goes further to explain what a structured snippet actually is, with a concrete header/values example. It is unmistakable against the other create_*_asset siblings by resource name, though it never explicitly contrasts itself with them (e.g. callout vs. snippet assets).

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?

It clearly states the critical usage fact that creation alone changes no ad and that the asset only shows once linked, naming the three concrete follow-up tools (link_asset_to_campaign, link_asset_to_ad_group, link_assets_to_customer). That is strong when-and-how guidance, but there is no when-not guidance (e.g. when to prefer text or callout assets instead).

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