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

With no annotations provided, the description carries the full burden. The verb 'List' clearly implies a read operation with no modification, and it mentions query filtering, but it does not explicitly state side-effect-free behavior, authentication requirements, or rate limits. It is adequate but not rich.

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 a clear one-sentence purpose followed by a practical usage note. The 'Routing' line is slightly redundant with the first sentence, but overall every sentence earns its place without unnecessary verbosity.

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?

Given no output schema, the description compensates by naming the return fields (SKU, quantity, product association). It covers purpose, filtering, and use case. It does not discuss pagination beyond the schema's limit parameter, but for a simple list tool it is adequately complete.

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%, so the baseline is 3. The description adds a small amount of meaning by explaining that `query` uses 'Shopify search syntax' and filters by 'product/variant,' but it does not materially extend beyond what the schema already documents.

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 uses a specific verb+resource ('List product variant inventory levels') and clearly distinguishes from sibling tools like list_shopify_products (product-level) and adjust_shopify_inventory (modifies). It also names the key output fields (SKU, quantity, product), making the tool's scope immediately clear.

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 states a clear use case: 'Use to check current stock levels before restocking or listing decisions.' It implies a read-only role versus adjust_shopify_inventory, but does not explicitly name alternatives or exclusions, so it stops short of a 5.

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