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

With no annotations, the description carries the burden of explaining behavior. It describes how the AR tool works (phone camera, A4 reference scale) and what the visualizer does (renders in uploaded photo), but does not mention return format, permissions, or side effects. Adequate for a simple URL retrieval tool, but not deeply transparent.

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?

The description is three sentences, front-loaded with the primary purpose, and includes essential details without redundancy. Every sentence contributes meaning, making it highly concise and well-structured.

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?

The description adequately explains the tool's context and usage for selection and invocation. However, with no output schema, it does not explicitly state that the tool returns a URL, which is implied by the name but could be clearer. Overall, complete enough for the tool's simplicity.

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%, so baseline is 3. The description adds minor value by explaining the mode options ('measure', 'visualize', 'both') and giving a product_id example, but largely repeats what the schema already states. It does not significantly deepen parameter understanding.

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 clearly states the tool's function: 'Surface the AR measurement tool or product visualizer' with specific use cases (measuring windows, previewing blinds). It distinguishes this tool from siblings by focusing on AR/visualizer functionality, which no other sibling addresses.

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?

The description explicitly states when to use the tool: 'when a customer wants to measure their window or preview a blind in their room.' It does not explicitly contrast with alternatives, but the sibling set clearly lacks any AR/visualization tool, so usage context is well implied.

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