remove_background

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

With no annotations, the description fully covers behavioral traits: returns JSON with url (public PNG, expires ~24h) and file_size_bytes, error conditions (bad URL or format), no side effects, no raw bytes (avoids context bloat), and cost ($0.03 per call). This is comprehensive.

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 a single paragraph but packs essential information: what, how, output, errors, side effects, cost. It could be slightly more structured (e.g., bullet points) but is not overly long or rambling.

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, the description adequately covers output format (url, file_size_bytes), expiration (24h), error handling, side effects, and cost. It also provides workflow guidance for local images. No gaps remain.

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 image_url well (100% coverage), and the description adds valuable context: must be public, accessible from internet, no local paths/data: URIs, and the workflow to pass local images via upload_file.

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 clearly states it removes background from an image using U²-Net via fal.ai, returning a transparent PNG on a public URL. This is distinct from sibling tools like screenshot_url or fetch_html, all of which are text/structure/fetch tools, making it unique and unambiguous.

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 explains when to use (to remove background), how to pass local images (upload first via upload_file), and cost details. It does not explicitly mention alternatives or when not to use, but that is acceptable given no similar sibling tools.

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