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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true), it discloses that creation is atomic with mandatory minimum assets and that new groups default to PAUSED — both meaningful safety-relevant traits. It says nothing about failure/partial-failure behavior or permission requirements, so it is strong but not complete.

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 and dense — every clause carries information an agent needs. The long parenthetical list and em-dash chaining make it a run-on that slows parsing slightly, but little could be cut without losing semantics.

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 16-parameter, 10-required mutation tool, the description covers the asset prerequisites, their source tools, the extra-assets escape hatch, dry-run mode and the default status. With an output schema available and annotations covering the safety profile, nothing essential for a correct call is missing.

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 gives cardinality (3 headlines, 2 descriptions), maps nearly every required asset-ID parameter to its asset type, documents extra_assets' item shape and a YOUTUBE_VIDEO example, explains validate_only and the workspace slug rule. campaign_id, name, final_url, path1 and path2 remain undocumented, keeping it below 5.

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+resource (create an asset group for a PMax campaign) and adds the decisive scope detail that creation is atomic with Google's minimum asset set. This clearly separates it from siblings like ads_add_asset_group_assets, which attach assets to an existing group.

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?

Explicitly routes the agent to ads_create_text_assets and ads_upload_image_asset for obtaining required asset IDs, and names validate_only=True for a dry run. It never states exclusions (e.g. that the campaign must already exist or that this isn't for adding incremental assets), so it stops short of a 5.

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