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

Annotations only say it is a non-read-only, non-destructive, non-idempotent write, which is thin for such an unusual tool. The description supplies the context annotations cannot: the server has no disk access, the call is a two-phase handshake rather than the transfer itself, and uploads expire after 24 hours.

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 short sentences, each carrying distinct information, with the blocking constraint front-loaded so an agent cannot misread this as a normal file-upload call. No filler or restatement of the title.

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?

An output schema exists, so return values need not be enumerated, yet the description still flags the two useful return elements (upload id and ready-to-run command) that drive the next step. For a two-phase tool this covers everything an agent needs to avoid a failed call.

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 67% and the two required parameters (filename, bytes) are already well documented in the schema. The description adds only a loose hint about accepted file kinds ('a mesh or picture') and says nothing about content_type, the one undocumented parameter, or why the byte size must be supplied when the file never reaches the server directly.

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 and non-obvious mechanism: it does not transfer the file itself, it returns an upload id plus an exact curl command the agent must run. Naming the constraint ('The server cannot read the user's disk') immediately separates it from generate_model and other siblings that consume 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?

It gives the full sequencing: call this, run the returned curl command, then pass the id as the image or mesh of another tool. That is clear when-to-use guidance. It stops short of naming which sibling to pass the id to (generate_model vs generate_texture vs edit_model) or what to do if a 24-hour upload expires.

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