set_freestyle

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

With no annotations, the description carries the full burden and does a reasonable job: it discloses the side effect that a line set is created if missing, that 'edges' replaces the current choice (not additive), and that the return is the post-change Freestyle state. It omits render-engine/permission prerequisites, which keeps it from a 5.

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?

The purpose is front-loaded in one sentence and the detail is organized as an Args block, so it is easy to scan. The edge-type list is long but every entry earns its place given the 0% schema coverage; the 'Returns' section is only mildly redundant with the output schema.

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 6-parameter mutation tool with no annotations and zero schema coverage, the description covers all parameters, the mutation side effects, and the return shape. The remaining gap is environmental context — which render engines support Freestyle and whether it must be toggled on first — which an agent needs to use it successfully.

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 fully, and it does: thickness range 0.1-10000 px, color normalized 0.0-1.0, crease_angle in degrees 0-180 with its meaning, and a fully enumerated list of edge types with per-value explanations (SILHOUETTE, BORDER, CREASE, EXTERNAL_CONTOUR, EDGE_MARK, etc.). This is meaning an agent could not recover from the bare schema types.

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 first sentence gives a concrete verb ('Draw ink lines') and resource ('over the render') plus the visual idioms it serves (outlines, toon, technical-drawing). It clearly identifies this as Freestyle line rendering, though it does not distinguish itself from the sibling add_lineart tool, which an agent could plausibly confuse it with.

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?

'Applies to the active view layer's line set (created if needed)' implies the operating context, but there is no explicit when-to-use guidance, no prerequisites (e.g. Freestyle must be enabled in render settings), and no routing to or away from alternatives such as add_lineart.

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