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

Annotations already declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=false, so safety is covered. The description adds character limits and the return shape, which is useful, but it does not warn that the non-idempotent behavior means repeated calls create duplicate assets, nor does it state account-access requirements.

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?

Front-loaded with the action and scope, then a short usage line and compact Args/Returns block. The Returns section is slightly redundant given an output schema exists, but overall the text is tight with no wasted sentences.

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 two-parameter creation tool with an output schema, the description covers both parameters, the character-limit constraint, and the returned resource name. Missing only cross-tool workflow context (create here, then link) which would complete the picture.

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 carries the burden and largely meets it: it explains customer_id must be numbers only with no hyphens, and maps text to per-type character limits (30/90/90). Only omission is that the caller must pick a type implicitly via the limit, with no parameter for it.

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 (create text asset) and narrows scope to Performance Max asset groups, listing the three text sub-types it covers. It differentiates implicitly from siblings like create_call_asset or create_image_asset by naming text asset types, though it never names an alternative explicitly.

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?

"Use this to create headline, description, and long headline assets that can be linked to asset groups" gives implied usage context, but there is no when-not guidance, no mention that linking requires add_assets_to_asset_group or link_asset_to_ad_group, and no prerequisites (permissions, campaign type).

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