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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false. The description adds that it fetches only the public page and performs no speed test, which is useful scope information, but it does not disclose authentication needs, rate limits, or error behavior.

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?

Two sentences with zero waste. The core purpose is front-loaded, and the second sentence adds a precise scope qualifier that earns its place by preventing confusion with the speed-test sibling.

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 simple detection tool with one required parameter, rich safety annotations, and no output schema, the description is nearly complete: it explains what is detected and what is not done. The only gap is the undocumented url parameter, but its name and role are self-evident.

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 single required parameter 'url' has 0% schema description coverage, so the description carries the full burden. It implies a site URL through context ('a site', 'fetches only the public page') but never states the parameter name, required status, or format, leaving the agent to infer from the schema alone.

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 (detect) and resource (Shopify theme store or headless storefront, plus theme), and distinguishes itself from the speed-test sibling by explicitly saying it 'runs no speed test.' An agent can tell exactly what this tool does without opening the schema.

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 gives clear context: use this to identify Shopify store type and theme, and it explicitly excludes speed testing ('runs no speed test'), which implicitly routes speed testing to the sibling check_shopify_store_speed. It stops short of naming that alternative directly, but the condition for selection is clear.

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