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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive behavior. The description adds valuable context about current operational limitations, specifically that it may return 'not_found' until redeployed and 'credentials_required' if Etsy keys are not provisioned. This goes beyond annotations and helps the agent anticipate failures.

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 concise and front-loaded with the primary purpose in the first sentence. The second sentence provides essential operational caveats without unnecessary filler. Every sentence earns its place, and the structure is clear and scannable.

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 list operation with no output schema, the description explains the scope (active listings, optional filter) and the current error states, which is important for invocation. It does not mention pagination behavior, but the schema covers limit/offset defaults. Given the tool's simplicity and annotations, this is sufficiently complete, though a brief note on return format would elevate 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?

The input schema has descriptions for 71% of parameters (5 out of 7), and the description adds only minor value by noting the keyword filter is optional. It does not elaborate on limit, offset, sort_on, or sort_order, but the schema already covers these adequately, so the baseline 3 is appropriate.

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 purpose: 'List one Etsy shop's active listings, optionally keyword-filtered within the shop.' It specifies the resource (one Etsy shop), the action (list listings), and scope (active, keyword-filtered). This distinguishes it from siblings like get_etsy_listing (single listing) and search_etsy (cross-shop search).

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 conveys clear usage context by identifying that it operates on a single shop and allows optional filtering, implicitly differentiating it from broader search tools. However, it does not explicitly state when not to use this tool or name alternative tools, so it lacks the explicit 'when/when-not' guidance of a 5.

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