Upload Media

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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false and destructiveHint=false, so the safety profile is covered. The description's one genuine addition is that it 'Returns its key' — essential here because there is no output schema — but it says nothing about size enforcement failures, account/permission requirements, or the fact that repeated uploads create new objects (non-idempotent).

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?

A single front-loaded sentence with no filler: verb and resource first, then the two use contexts, then the return value. Nothing redundant with the schema is repeated beyond the brief format list.

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 one-parameter tool with no output schema, the description covers what the tool does, the accepted media types, and — critically — that the result is a key usable as an AI ref or clip cover. What is missing is any note on where the returned key is consumed or what happens on failure/duplicate upload, but the essentials are present.

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?

There is only one parameter and the schema already documents it exhaustively with absolute-path requirement plus per-format size ceilings (100% coverage). The description adds only that the file is 'local', which is already implied by 'path'; baseline 3 is appropriate when the schema carries the parameter semantics.

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 ('Upload a local image, song or short video to the account's media') and names the two consumer contexts for that media (AI inputs via refs kind 'media', or a clip cover). That framing lets an agent separate it from siblings like set_cover (which acts on already-uploaded media) and ai_generate (which consumes it).

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?

The description supplies the two downstream purposes ('for AI inputs ... or a clip cover'), which implies when an agent should reach for it, but it never names an alternative tool or an exclusion. There is no guidance on prerequisites (must the file exist locally? which account?) or on what to do if the upload fails or a duplicate exists.

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