preview

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

No annotations, so the description carries the full burden. It discloses the output type (image), that unset camera means automatic viewall framing, and the performance/accuracy tradeoff of full_render — genuinely useful. It omits error behavior, timeout semantics, and any prerequisites (e.g. whether a file/source must be loaded first).

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-loads the one-line purpose, then walks parameters in a logical order. The multi-sentence camera explanation is long but earns its place given the non-obvious two numeric-string formats.

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 10-parameter tool with no annotations, no output schema, and 0% schema coverage, the description covers the rendering options well but leaves core inputs (file, source), defines, imgsize, colorscheme and timeout undocumented. Minimum viable, with clear gaps an agent must guess around.

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 across 10 parameters. It richly documents the two hardest ones (camera's 7-number gimbal vs 6-number eye/centre forms, projection values) plus viewall and full_render, but leaves file, source, defines, imgsize, colorscheme, and timeout_s entirely unexplained — notably the file-vs-source distinction.

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+resource: render a PNG of the model and return it as an image. It also implicitly hints at the preview/render distinction via 'preview approximation' and 'what will export', but it never names the sibling 'render' to route the agent explicitly.

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 useful guidance on individual options (camera formats, projection, when to use full_render) but offers no explicit when-to-use-this-vs-`render`-or-`check` guidance. Usage is implied through parameter semantics rather than stated selection criteria.

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