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

Annotations declare readOnlyHint=true, so safety is covered. The description adds non-obvious behavioral context: each call adds a new view to the conversation, and the wireframe is interactive (menus open, links move between screens). However, it doesn't explain what happens if the mockup target is invalid or how rendering failures are surfaced.

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 sentences, each front-loading essential information: what it does, when to use it, and the alternative. No filler or redundancy.

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 tool with one parameter and no output schema, the description covers the key behavioral traits and usage rules. It does not explain the 'mockup' parameter format, which would help an agent construct the call correctly, but otherwise it is complete enough.

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 100% for the single 'mockup' parameter, but the schema description is minimal ('The mockup target'). The tool description implies the parameter is a mockup identifier or reference, but does not clarify the expected format (ID, name, path). With one parameter and full schema coverage, the baseline is 3, but the description adds marginal value by implying the target is something that can be presented. However, it does not compensate for the vague schema description.

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 ('Present') and resource ('a mockup'), and goes further by describing the rendering modality (hand-drawn wireframe inline in chat). It explicitly distinguishes itself from get-mockup by naming the sibling and contrasting purposes.

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?

Explicitly states when to use it (user asks to see a mockup; once after completing a batch of edits) and when not to (not per edit). It also names the alternative tool (get-mockup) and the condition that selects it ('for reading the markup for your own reasoning').

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