design_trace_values

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

No annotations are provided, so the description carries the full behavioral burden, yet it says nothing beyond the output type. It does not state whether a trace layer is added to the document (createLayer defaults to true per schema), whether existing layers are affected, what happens on repeated invocation, or how the source image is resolved.

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?

Two short sentences with the output artifact front-loaded and no filler. It is efficient, though the second sentence is thin enough that the brevity comes partly at the cost of information.

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?

With five parameters, no annotations, and no output schema, the description should explain the mutation footprint, the default behavior of createLayer, and what the resulting map looks like. Neither the return value nor the document side effects are covered, leaving meaningful gaps for a generative/mutating tool.

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% and every parameter (invert, levels, contrast, sourceId, createLayer) is documented with defaults in the schema. The description adds no syntax or default information beyond that, so the 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 a specific verb and resource: 'Generate a value (lightness) map from the image' — an agent knows exactly what artifact comes out. It does not, however, distinguish itself from the many trace siblings (design_trace_edges, design_trace_contours, design_trace_regions, design_trace_stipple), so the choice among them is left to guesswork.

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?

'Useful for tonal studies' implies a context of use but gives no explicit when-to-use/when-not, no prerequisites, and no named alternative among the trace_* family. The agent must infer that this is the greyscale/value option rather than the edge or contour tracer.

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