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

Annotations cover only the safety profile (readOnlyHint=false, destructiveHint=false, openWorldHint=false), while the description discloses substantial extra behavior: the signed PUT flow and curl line, the 1 GB cap, accepted formats, 60-minute URL validity, and the BETA tier/export limits. This is exactly the kind of operational context annotations cannot carry.

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 decision-critical clause ('FIRST CHOICE when the file is in your sandbox'), then constraints and limits in compact form. The beta tier/export sentence is the least essential part and inflates length slightly, but the whole still reads as purposeful.

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?

No output schema exists, and the description compensates by explaining the return ('the response is the managed asset') plus size, format, and expiry constraints. It covers what an agent needs to invoke and interpret the result; only the non-sandbox alternative path is left implicit.

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?

At 50% schema coverage, brand, sku and filename are undocumented in the schema, and the description only enumerates them ('filename required, plus tags/brand/asin/sku/type') without adding meaning beyond the schema's own required list. The richer field semantics (asin lookup, namespaced tags, type values) already live in the schema, so the description adds little.

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 ('Returns a signed PUT URL for one file') and pins its scope to files in the sandbox, which distinguishes it from the URL-based siblings like video_asset_import_url and video_upload_link. An agent can identify the operation and its target 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?

'FIRST CHOICE when the file is in your sandbox (a chat attachment you can read)' gives a clear selection condition, and 'Call video_guide first' routes the agent to prerequisite context. It stops short of naming the alternative tool for the non-sandbox case, so the contrast is implied rather than explicit.

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