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

Annotations already declare readOnlyHint/destructiveHint=false, and the description reinforces this with 'It changes nothing' while adding a genuine constraint not in the annotations: only what is listed can be applied. It stops short of describing what the returned list looks like, which matters somewhat since there is no output schema.

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?

Three short sentences: purpose and example first, the applicability constraint second, the exclusions last. There is no filler, and the phrase 'It changes nothing' is a deliberate, load-bearing safety signal rather than padding.

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 read-only two-parameter tool with a nested, fully documented state object, the description covers purpose, constraint, and exclusions adequately. The only gap is the shape of the result — whether it returns categories, named options, or matching graphics — which the description only gestures at.

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%, including a specific note that `state` must be passed exactly as returned by the last Webba tool result and not edited by hand. The description adds no parameter-level meaning beyond noting the search example ('stacked boxes'), so the schema is doing the heavy lifting.

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 description gives a concrete verb and resource: it returns what a chosen Webba design can change and can also search the builder's available graphics. It explicitly separates itself from update_design (making a change) and from externally made logos, so an agent can pick it over its siblings without inspecting schemas.

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?

It states exactly when to reach for it ('when the person asks what a chosen Webba design can change', or to search graphics like 'stacked boxes') and when not to ('Do not use this to make a change, which is update_design, or for logos made elsewhere'). Both the positive trigger and the named alternative are present.

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