upload_image_asset

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

With no annotations provided, the description carries the full burden and does substantial work: it discloses the 'Draft... on apply' two-phase semantics, the dedupe behavior (byte-identical re-uploads return the existing media id), and the unwrapped AddMedia response quirk. This is far beyond a bare 'upload' claim, though it does not state authorization or reversibility 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?

The description is front-loaded with the primary purpose and enumerates media_type values as a scannable bullet list. The live-verification note and dedupe behavior add genuine value despite some verbosity in the fault-fixing narrative. Every major section earns its place, though it runs slightly long.

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?

Given no output schema and no annotations, the description correctly explains the return value (media id on apply) and documents the enum-like media_type values. But with 2 required parameters, file_path remains ambiguous (format, source, extension constraints), which could lead to incorrect calls, and the 'apply' step of the draft workflow is not connected to any sibling (e.g., confirm_and_apply).

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 coverage is 0%, so the description must compensate. It thoroughly documents media_type with aspect ratios and concrete dimension examples (1200x1200, 1200x628), which the bare string schema does not convey. However, file_path is left entirely to its name — the description never clarifies whether it is a local path or URL, or the allowed file formats beyond the passing note 'PNG/JPEG'. Compensation is partial.

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 states a specific verb and resource ('Draft an image upload to the account media library'), names the target use cases (image extensions / PMax asset groups), and specifies the return value (media id on apply). This clearly distinguishes it from sibling tools like draft_responsive_search_ad or create_custom_audience, which operate on different resources.

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 gives clear context by scoping use to 'image extensions / PMax asset groups', which helps an agent know when this tool applies. However, it never explicitly names alternatives or states when NOT to use it (e.g., other asset types like video or HTML5), so exclusions are left implicit.

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