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

Annotations declare non-read-only, non-destructive, non-idempotent; the description confirms and enriches this by stating a NEW asset is created, the original is untouched, the name gets an '(HD)' suffix, and a 24h download link is returned. It also discloses runtime ('about as long as the video lasts') and a named failure mode (ALREADY_HD) — detail that goes well beyond the annotation surface.

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?

Front-loaded with the action and output resolution, then constraints, then side effects, then the failure mode — dense semicolon-separated clauses with no filler. Every sentence carries information an agent needs to decide or call correctly.

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?

Even without an output schema, the description explains the return value (new asset plus a 24h download link), the naming convention, the untouched original, and the key error case. Nothing needed to call this tool correctly is missing.

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?

Only one parameter with 100% schema coverage, so the schema already documents that 'asset' accepts an id from search_assets or an exact name. The description adds nothing about parameter format, so the baseline 3 for full schema coverage 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?

Specific verb (upscale) plus resource (video asset) with precise output spec (1080 on short side, 1080x1920 vertical) and the exact processing pipeline. It is clearly a distinct operation from update_asset, upload_asset, or get_asset_download_url in the sibling list.

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?

Gives strong when-to-use context: videos only, max 150 s, and videos already at 1080+ are refused with an ALREADY_HD error. The contrast with an AI-based alternative is implied ('No AI... no detail is invented') but that alternative tool is never named, so no explicit routing is provided.

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