Preview a build before placing it

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

With no annotations present, the description carries the behavioral disclosure burden, and it does well: it states the tool is read-only ('Nothing is changed in the world'), describes both return artifacts, and explains the context>0 behavior. It could additionally mention access requirements or output-file lifecycle, but the core side-effect and output behavior are clearly disclosed.

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 tight sentences front-load the main action, specify outputs, and end with the key safety property. Every sentence earns its place and there is no filler.

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?

This is a complex tool: seven top-level parameters, nested alternatives, no output schema, and no annotations. The description gives only a high-level overview and omits mode exclusivity, default/limit behavior, return structure, and how the HTML path is delivered, so it is not complete enough for reliable autonomous invocation.

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 description coverage is only 29%, so the description needed to compensate, but it only clarifies context>0 and loosely groups the three input modes. It does not explain that build/shape/schematic are alternative sources, what max_layers controls, how world/title are used, or the expected output contract.

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 uses a specific verb ('Render') and identifies three input kinds (build spec, shape, schematic) plus the two output forms (ASCII slices and a 3D HTML viewer). It also states 'Nothing is changed in the world,' which distinguishes it from placement-style sibling tools, though it does not name those siblings 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?

The title 'Preview a build before placing it' and the note that nothing changes in the world imply this is for verification rather than execution. However, the description never explicitly tells the agent when to choose preview over build, place_shape, or paste_schematic, nor does it state that no world modification will occur as a reason to prefer it.

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