model_addon

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

With no annotations the description carries the full burden and does well: it discloses that query actions change nothing, build actions add objects as one undoable step, and look:true returns an image. It omits permissions, error behavior, and whether add-ons must be loaded beforehand.

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?

Dense, front-loaded, and free of filler; the list/run/look structure is easy to parse. The telegraphic syntax ("look:true returns a picture") is terse to the point of being slightly cryptic but still readable.

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?

Without an output schema the description must describe returns, and it only partly does (listing contents, advice, picture). Two parameters (layout, label) and any failure modes are unexplained for a tool with six optional params and nested args.

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 0%, so the description must compensate. It explains addon (with valid built-in values), action (with example names), args (via the listing's argument docs), and look; but layout and label are never mentioned, leaving two of six parameters undefined anywhere.

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 concrete resource (3D add-ons) and enumerates the built-ins ("gears", "welding") plus the three operating modes (list, run, render). An agent can tell it is not a generic model tool, though nothing explicitly differentiates it from siblings like mechanism or model_build.

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?

Gives explicit mode-selection rules: omit addon to list, supply addon+action to run, add look:true for a picture. It also separates query from build actions. It stops short of saying when to prefer this tool over sibling tools.

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