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

Annotations establish the safety profile (not read-only, not idempotent, not destructive), and the description adds meaningful context beyond that: the address is one-time, the server measures the file on arrival, and validation (size, format, storage) happens in finalize_upload. It doesn't cover failure modes or address expiry, keeping it out of 5 territory.

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?

Four sentences, front-loaded with the purpose and immediately followed by the workflow. Mostly efficient, though the 'Never ask the artist how big a file is' instruction slightly duplicates the bytes schema note.

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 non-idempotent tool with no output schema and 7 parameters, the description covers the critical path well, including what gets returned (the address) and how validation is deferred to finalize_upload. The unaddressed kind enum and a few secondary params leave a small gap.

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 57%, and the schema itself carries rich descriptions for filename, bytes, artist, and track_id. The description reinforces that only the filename is truly needed and that bytes should never be solicited, but it says nothing about the kind enum, album_id, or mime_type, which remain undocumented in both places.

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?

The description states a specific verb+resource: requesting a one-time upload address for a master, cover art, logo, or artist photo. It scopes the tool precisely enough that an agent can tell it apart from finalize_upload, which it names as the downstream step. Purpose is unmistakable.

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?

It lays out the workflow clearly: ask for the address, PUT the file, then call finalize_upload. It also states what input is needed ('the file's NAME, nothing else'). It does not explicitly contrast with non-upload siblings or state when not to use it, so it falls short of a full 5.

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