upload_image

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

No annotations are provided, so the description carries the full behavioral burden. It discloses the SSRF guard on image_url, the https-only/no-private-host restriction, and the fact that the call returns a file_id for downstream use. It does not mention permissions, persistence, or size limits, but the most critical behavioral traits are covered.

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 compact and front-loaded: it states the action, the critical either/or rule, the security constraint, the return value, and the workflow note in three sentences. Every sentence earns its place.

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?

There is no output schema and no required parameters in the schema, so the description must compensate. It explains the return value, downstream usage, and the chat_card sequencing. It could mention image format or size constraints or clarify behavior if both image_url and image_base64 are provided, but the core calling information is present.

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 100%, so the baseline is 3. The description adds meaningful semantics beyond the schema: the either/or constraint between image_url and image_base64, the SSRF/private-host behavior, and the relationship to create_ad's file_id. These details help the agent invoke the tool correctly despite the schema not marking either parameter as required.

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 uses a specific verb ('upload') with a distinct resource ('creative image for ads') and clarifies that it feeds into create_ad through a returned file_id. This makes it easy to distinguish from sibling tools like upload_audience_file or create_ad.

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 clearly explains that the agent should provide either image_url or image_base64 and includes the important chat_card workflow: upload first, then create_ad. It does not explicitly list alternatives or say when not to use the tool, but the context is sufficient for correct selection.

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