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

Annotations already declare the write/open-world/non-destructive profile, so the description only needs to add outcome detail. It does: an image becomes a photo, and imported media gets the same thumbnails, waveform and proxy processing as native media. It omits whether the fetch is synchronous or long-running (relevant given sibling job_status/cancel_job).

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?

Two front-loaded sentences cover capability and outcome with little waste. The 'joins the project' clause appears twice, which is minor redundancy rather than bloat.

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?

For a four-parameter mutation with no output schema, the description covers what gets imported and how it is processed, but says nothing about return value (e.g. a media id or job handle) or failure/timeout behavior when a third-party site is unreachable.

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 nothing parameter-specific — audioOnly and maxHeight are never mentioned — though the site list and image-as-photo note loosely clarify what url can accept.

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 (download a link's target into a project) and enumerates the source kinds: posts on YouTube, X, Instagram, TikTok, or a direct video/audio/image file. This implicitly separates it from upload_media (local files) and search_footage, but no sibling is named explicitly.

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?

'Download what a link points at' implies the trigger condition — you have a URL rather than a file — but there is no explicit when-to-use/when-not guidance and no pointer to alternatives such as upload_media or search_footage.

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