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

Annotations already declare the non-readonly, non-idempotent, non-destructive profile. The description adds real behavioral value beyond them: the two-step HTTP PUT workflow, both return values (uploadUrl and publicUrl), and the intended downstream use. It omits URL expiry, size limits, and auth requirements, which keeps it from a 5.

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 sentences, front-loaded with the core action, followed by the workflow and the alternative routing. Every sentence carries distinct information with zero padding.

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 usefully names both returned URLs and explains how to consume them. It is largely complete for a two-parameter tool, though URL lifetime and payload constraints would round it out.

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 50% — contentType is documented in the schema while filename is not. The description implies content type ('image/video') and the artifact being uploaded but adds no format or constraint detail beyond the schema, so the baseline 3 is appropriate.

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 and resource ('Get a presigned PUT URL to upload an image/video') and precisely distinguishes the tool from a named sibling ('Prefer import_asset_from_url when you already have a URL'). An agent can identify the tool's role without opening the schema.

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?

Provides explicit when-to-use ('upload an image/video directly'), when-not with alternative ('Prefer import_asset_from_url when you already have a URL'), and the downstream workflow ('pass publicUrl to a generation call'). Nothing about selection is left to inference.

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