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

With no annotations, the description carries the full burden and does well: it discloses that runs dispatch to Modal workers, that credits vary by model/file size, that Day Pass/welcome credits are excluded, that files are deleted after processing with a retention link, and that one credit pack unlocks all workspaces. It omits confirmation of whether the operation is reversible or synchronous/asynchronous.

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 core purpose is front-loaded in the first sentence, but the remainder is largely pricing/billing boilerplate (credit packs, Day Pass, pricing page) that is only marginally relevant to invoking the tool, diluting a description that should focus on the operation.

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 zero params, no output schema, and no annotations, the description supplies enough behavioral context (async AI worker dispatch, credit variability, file deletion, retention link) for an agent to call it and set expectations. It lacks output/return details, but none are otherwise available.

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 tool has zero parameters (schema coverage 100% trivially), so there is nothing for the description to clarify; the baseline of 4 applies. The description mentions inputs the agent supplies (target subject, background choice) though these are not schema parameters.

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: 'AI Video Background Remover' with a clear workflow — describe subject to keep, choose a background type. It clearly distinguishes itself from the image-oriented siblings (remove_background, remove_background_pro) by its 'Video' qualifier.

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?

Describes the operational workflow (describe person/object to keep, then pick background) which implies how to use it, but gives no explicit when-to-use vs when-not guidance and never names an alternative tool for a still image vs video choice.

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