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

Adds real value beyond the annotations by ruling out side effects ('Nothing is generated or charged') and disclosing the quote_token artifact that the next step depends on. 'Short-lived' is left vague (no TTL), and it doesn't say what happens if the quote expires, so it stops short of full disclosure.

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?

Front-loaded with purpose and the no-charge guarantee, then dense tier/format guidance with little filler. The closing sentence 'prepare_3d_generation returns the exact credit cost' merely repeats the opening and is wasted space.

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?

Given an output schema exists and annotations cover safety, the description supplies the workflow ordering, cost-preview semantics and tier/format rules an agent needs. The omission of the `image_url` input path is the one real gap for a 5-parameter, branching tool.

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 only 60%, and the description compensates by explaining quality tiers with their resolutions (256³/384³/512³) and the per-tier export format constraints (stl/glb/obj/ply vs stl/glb/obj/fbx, texture variants glb/obj with obj as a zip) — constraints absent from the schema. It never mentions `image_url` (the fourth input path) or the format default, so it isn't complete.

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 and resource ('Step 1 of AI 3D generation... validates the prompt... returns the exact credit cost') and positions itself in a sequence, making it clearly distinct from generate_3d_model (which actually generates) and check_3d_generation. An agent can pick the right one without opening the schema.

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?

Explicit routing: 'Show the user the cost and settings, then call generate_3d_model only if they agree', plus explicit branch conditions ('Text: pass `prompt`. Image-to-3D: pass the attached image as `image`'). It even gives guidance on which input suits high-resolution tiers.

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