Upload a local image

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

Annotations only report readOnly=false and destructive=false, so the description adds value by disclosing that no credits are charged and that a public URL is returned. This gives the agent useful behavioral and cost-related context beyond the generic annotation hints.

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?

Three short sentences, each earning its place: what the tool does, how to use the result, and a cost note. The core action is front-loaded without extraneous detail.

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?

With no output schema, the description correctly explains the return value as a public fal URL and shows how it feeds into sibling tools. It is complete enough for a one-parameter upload utility, though it could briefly mention error behavior.

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?

The schema already documents filePath with absolute path, allowed formats, and the 10 MB limit, so schema coverage is 100%. The description adds little parameter-specific meaning beyond framing the intent; it stays at the baseline of relying on the schema.

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?

Description names the specific verb 'Uploads', the resource (local image file), and the result (public fal URL). It also clearly distinguishes the tool from sibling generation tools by explaining its role as a prerequisite for them.

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 gives clear context: use this tool to turn a local photo into an inputImageUrl for editing, face-swap, or image-to-video. It names the downstream tools but does not explicitly state when not to use it, so it stops short of a full when/when-not guide.

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