preview_layer

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

With no annotations, the description carries the whole burden. It usefully discloses rendering behavior (filament colors, zoom framing extrusions vs. whole bed) and the slice-project dependency, but never states that the operation is read-only/non-destructive, what the error looks like if slicing hasn't run, or how the image is delivered.

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 what the tool returns, then the prerequisite, then parameter selection rules, then rendering detail. Dense, zero filler, no restating of the name.

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 no-annotation, no-output-schema tool the description supplies what an agent needs: the return is an image, the prerequisite is named, and selection semantics are covered. The unexplained plate parameter and unstated non-destructiveness are the remaining holes.

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, and it largely does: it defines layer numbering (1 = first), z as height in mm, and both zoom states with the default. Only 'plate' (default 1) is left completely unexplained, which is the one gap preventing a 5.

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?

It states a concrete verb+resource: renders an image of a single sliced layer viewed from the top, with a styling detail (extrusions in filament colors). That clearly separates it in spirit from the plate-level sibling preview_plate, but it never names that sibling, so the differentiation is inferred rather than stated.

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?

'needs slice_project first' gives the agent an explicit precondition, which is the main usage trap for a preview-after-slice tool. There is no explicit guidance about when to prefer preview_plate or preview_layer, so it falls just short of full alternatives coverage.

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