design_generate_color_variants

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

With no annotations, the description carries full behavioral burden. It does disclose a meaningful side effect — four new layers are created and automatically arranged on the canvas — which is real value. It omits whether the source lockup is modified, what happens on repeat invocation (duplicate stacks?), and any permission/state prerequisites.

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, zero filler, with the output of the operation front-loaded in sentence one and the side effect in sentence two. Nothing is redundant with the 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 two-parameter, no-output-schema tool this is adequate but not complete: the description never states that the target must already be a lockup layer versus any layer, nor what the agent should do if the layer is not a lockup. The generated-layer outcome is covered, but prerequisites and failure modes are not.

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%, with both layerId and spacing documented in the schema itself, so the baseline is 3. The description adds nothing about the spacing parameter (e.g., whether it is a gap in pixels between the generated layers) beyond restating that the layers are "arranged on the canvas."

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?

Uses a specific verb ("Generate") plus a concrete resource ("color variants of a lockup layer") and enumerates the four variant kinds (full, reversed, grayscale, mono). It does not, however, distinguish itself from the closely related siblings design_create_lockup and design_set_lockup_variant, so an agent cannot tell which of the three to reach for from this text alone.

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?

Usage is only implied: the input must be "a lockup layer," which hints at the prerequisite of an existing lockup. There is no explicit when-to-use guidance, no exclusion of design_set_lockup_variant/design_create_lockup, and no note about whether to call this before or after creating the lockup.

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