design_update_blend

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

With no annotations, the description carries the full behavioral burden and delivers almost nothing: it does not say whether unspecified properties are preserved (partial patch) or reset, whether the layer must be selected/active, whether the operation is undoable, or what happens when layerId is invalid. 'Modify properties on an existing … layer' only weakly hints at a patch-style update.

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?

A single front-loaded sentence with no filler or redundancy. Its brevity is not padding, though the same minimalism is what creates the gaps scored elsewhere.

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 16-parameter mutation tool with no annotations, no output schema, and 13% schema description coverage, this description is far too thin — an agent would have to guess the semantics of nearly every parameter and the update/patch behavior before calling it.

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 13% across 16 parameters, so the schema documents essentially nothing on its own, and the description adds no parameter meaning at all — the mode/easing enums, the spine format ('[{x,y}]' vs "straight"), the interpolate* flags, and the start/end value pairs are all unexplained. The generic word 'properties' does not compensate for the coverage gap.

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 ('Modify') and resource ('existing shapes:blend layer'), so an agent can tell it is an update operation on a blend layer. However it never mentions the sibling tools design_set_blend or design_blend_shapes, so the boundary between 'update existing blend', 'set blend', and 'create blend' is left to inference.

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?

There is no when-to-use guidance, no statement of prerequisites (does the blend layer need to already exist / be selected?), and no mention of when to prefer design_set_blend or design_blend_shapes over this. The word 'existing' is the only implicit condition.

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