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

Beyond the readOnly/idempotent annotations, it discloses the render style, the echo fields (n_drawn, n_without_geometry, n_without_position, n_edges_failed), outlier exclusion, the highlight cap of 52, and that spaces are not drawn. It doesn't state the image size or what happens on an empty model beyond the count echo.

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 the output and its visual meaning, but the sentence about echo fields is a dense parenthetical of internal names and the aside 'nothing drawable answers the counts without a picture' is cryptic. The trailing 'Read-only.' duplicates the readOnlyHint annotation.

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?

There is no output schema, and the description covers the return artifact and echo counters, which is the key completeness requirement. However, for a tool with a large nested highlight filter, the description omits how highlight interacts with the frame or what the echo does when it refuses more than 52 elements.

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 100%, so the schema already documents view, storey, highlight and projection in detail. The description adds only a few hints (two sides show more than one, at-most-52 refusal, spaces not drawn) without supplementing parameter syntax, so baseline 3 applies.

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 the concrete output (a PNG wire picture of the model or one storey, edge-only, see-through) and the specific visual semantics (far edges lighter). It distinguishes itself from counting (find_elements) and measuring (compute_quantities) siblings, but does not mention the closer visual siblings draw_section and clip_elements.

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?

Explicitly says this is for visually inspecting your work and names two sibling alternatives with their proper use cases. It lacks guidance on when to prefer draw_section or clip_elements, or when a non-visual query is better, but the intent boundary is clear.

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