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

With annotations already covering safety (readOnlyHint=false, destructiveHint=false, openWorldHint=true, idempotentHint=false), the description adds real context: the file lands in the user's media library and the response contains an asset id and public URL. It does not mention that repeat uploads create new assets, but the non-idempotent hint covers that.

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 tight sentences, all front-loaded with purpose, then inputs, then return/usage. No filler or redundancy.

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 describing the return values (asset id, public URL) and how they feed schedules. For a 3-param upload tool with full annotation coverage, nothing an agent needs to invoke it 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?

Schema description coverage is 100%, so baseline is 3, but the description adds the mutual-exclusivity constraint between sourceUrl and contentBase64 that the schema only hints at. It still does not state that at least one of the two must be supplied, which the schema leaves ambiguous given only filename is required.

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 (upload) plus resource (image/video asset) and the reason it exists ('so it can be attached to a post'). This clearly separates it from sibling read tools like list_assets.

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?

Explains the input choice ('either sourceUrl ... or contentBase64') and downstream usage ('use as media_link in schedules'), giving strong context. It stops short of naming when to prefer a URL over base64 or pointing at a sibling for asset listing.

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